Dr. Matthew Walker: The Biology of Sleep & Your Unique Sleep Needs | Huberman Lab Guest Series

Welcome to the Hubman Lab Guest Series where I and an expert

guest

discuss science and science-based tools for everyday life. I'm Andrew Huberman and I'm a professor of neuro

biology

and ophthalmology at Stanford Medical School. Today's episode marks the first in our six-episode Sleep Series. Our expert

guest

in this

series

is Dr. Matthew Walker, professor of neuroscience and psychology and director of the

sleep

science center at the University of California, Berkeley. He is also the author of the best-selling book Why We Sleep During the Throughout the six-episode

series

, for which we release one episode per week, starting with this episode one, we cover essentially every aspect of

sleep

and provide numerous practical tools to improve

your

sleep, for example, we look at the

biology

of sleep, including the different stages of sleep.

To learn why sleep is so important for our physical and mental health, we also talk about how sleep regulates things like emotionality and learning and neuroplasticity, which is

your

brain's ability to change in response to experience, and We look at the various things you can do to improve your mental and physical health. sleep everything from how to turn on the temperature, exercise, eating, and the various things that can affect sleep both positively and negatively, such as alcohol, cannabis, and various supplements and medications that have been shown to improve sleep. We also talked about naps, dreams, and the role of dreams.

Lucid dreaming, which is when you dream and are aware that you are dreaming. In today's episode one, we focus specifically on why sleep is so important and what happens when we don't get enough sleep or not enough sleep. We also talked about the different types of sleep. stages and we also talked about a very specific formula that everyone should know for themselves called qqr T which is an acronym that stands for Quality quantity regularity and timing of sleep four factors that today you will learn to identify specifically for you what your optimal qqr is and then apply it to get the best possible night's sleep, which of course equates to the best possible level of concentration and alertness throughout your days.

Both Dr. Walker and I are very excited to share the material from the six-episode series with all of you and as we move into episode one today, I'm sure it will provide you with a lot of great practical learning and generate many questions that will surely be answered in later episodes of this series before I begin I would like to emphasize that this podcast is independent of my teaching and research duties at Stanford; however, it is part of my desire and effort to provide consumer information about science and science-related tools at no cost to the general public in accordance therewith. topic I would like to thank the sponsors of today's podcast our first sponsor is eight sleep eight sleep ago Smart mattress covers with cooling Sleep tracking and heating capabilities Many times in this podcast we discuss how to fall and stay deeply asleep your body temperature in reality It

needs

to drop between 1 and 3° and to wake up feeling as fresh and energized as possible, your body temperature

needs

to rise between 1 and 3°.

Eight hours of sleep makes it very easy to control the temperature of your sleeping environment, so it's easy to fall asleep, stay asleep, and wake up feeling refreshed. I started sleeping on an eight mattress cover several years ago and it has completely and positively transformed my sleep so much that when I travel to hotels or Airbnbs I really miss my eight. I've even sent my eight hours of sleep to the hotels I've stayed in because it improves my sleep so much. If you want to try eight hours of sleep, you can go to 8sleep.com

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to save $15 on their three capsule coverage.

Eight Sleep currently ships to the US, Canada, UK, select EU countries and Australia again, that's Eight Sleep.com Huberman. Today's Huberman episode is also brought to us by Betterhelp. Betterhelp offers professional therapy with a licensed therapist that takes place online. Now I've been doing therapy. For over 30 years, I initially had to do therapy against my will, but of course I continue to do it voluntarily over time because I truly believe that doing regular therapy with a quality therapist is one of the best things we can do for our health. mental. In fact, for many people it is as beneficial to their health as doing regular physical exercise.

The best thing about better help is that it makes it very easy to find a therapist that suits your needs and I think it's fair to say that we can define a great therapist as someone who you have a great relationship with, someone who you can talk to about a variety of different topics and can provide you with not only support but also information and with better help will make it extremely convenient to fit into your schedule and other aspects of your life, if you want to try Betterhelp you can visit Betterhelp.com Huberman to get 10% off your first month again.

That's Betterhelp.com Huberman. Today's episode is also brought to you by Element Element is an electrolyte drink that has it all. what you need and nothing you don't, that means lots of electrolytes, magnesium, potassium and sodium, and no sugar, as I mentioned before in this podcast. Now I'm a big fan of salt. I want to make it clear to people who already consume a lot. of salt or who have high blood pressure or who consume a lot of proc say that foods that normally contain salt need to control their salt intake, however, if you are someone who eats fairly clean and you are someone who exercises and Drinks a lot of water, There's a good chance you might benefit from getting more electrolytes with your fluids.

The reason is that all cells in our body, including nerve cells and neurons, need electrolytes to function properly, so we don't just want to be hydrated, we want to be hydrated with adequate levels of electrolytes with an element that is very easy to do. What I do is when I wake up in the morning I consume about 16 to 32 ounces of water and I dissolve one element packet in that water. I'll also do the same when I exercise, especially if it's a hot day and I'm sweating a lot, and sometimes I'll even dissolve a third element packet in water if I'm exercising really hard or sweating a lot or if I just notice I'm not getting enough salt. with my food, if you want to try element, you can go to drink element written LM nt.com

huberman

to claim a free element sample pack with your purchase again. that's drink element lnt.com huberman and now for my conversation with Dr.

Dr. Matthew Walker Dr. Matt Walker, welcome Dr. hubman, it's an absolute privilege and a pleasure to be back, that's right, you've been here before, but I did during this episode in this series, we are going to go much deeper because of the way you look very well rested, thank you very much. I actually slept pretty well last night, despite it being a foreign place, same time zone which helps, astronomically amazing, rather than wondering what. a good night's sleep is for you because I'm pretty sure you'll tell us that there are some individual differences that people need to pay attention to in terms of what's optimal sleep, quote unquote, let's start with the basics.

Sleep, so I think in some ways it can be defined as at least in humans and indeed in all mammalian species, is broadly separated into two main types of sleep. On the one hand, we have something that many people will have heard of called non-rapid eye movement. Sleep or non-rem sleep for short and non-rem sleep has been subdivided into four separate stages and they are unimaginatively called stages one to four which increase the depth of sleep, so stages three and four are the really deep sleep. that we can. I'm talking and I should explain a little bit at some point what happens during that state in the brain.

It's amazing, it's amazing, so you have stages one and two of light non-RM sleep when you look at your sleep trackers and it has light non-remote, deep, non-remote and then REM, stages one and two, which is light, no, stages three and four, which is deep, no and it is not encapsulated, on the other hand, we have rapid eye movement sleep or remm sleep and it is not named after the popular Michael. Styp band from the 1990s, but because of these strange horizontal eye movements that occur during this stage of sleep, rapid eye movements and REM sleep depend on your definition and we'll probably get to this in later episodes. main stage in which we dream, but if its definition is quite vague, which is any mental activity reported when you wake up or when you wake up, it turns out that we dream in almost all stages of sleep, but I will describe REM sleep from now on , maybe you dream the dream and I'll make that part fake so you have these two types of non-rem and REM sleep that will then play out in this beautiful battle for brain domination all night long and that brain sleep.

The war will be won and lost on average for the average adult every 90 minutes and then repeated every 90 minutes and that creates the standard cyclical architecture of sleep, so whoever is listening to this when your head hits the pillow tonight, what will happen? , you will start to descend into the light stages of non-slumber sleep, then you will descend into the deeper stages of non-slumber sleep and you will stay there and after about 45 50 60 minutes you will start to come back up and then you will emerge and have a short period of sleep REM and then you'll go back down, you'll go back down into non-REM sleep and you'll go up into REM sleep and like I said, you go through that on average about 90 minutes, but I'll come back to that.

However, the interesting thing is that the ratio between non-rem and REM within your 90-minute cycle is not stable and what I mean is that as you progress through the night, these two types of sleep dominate. within the 90 minute cycle changes so that in the first half of the night most of those 90 minute cycles are made up of a lot of deep non-REM sleep but very little REM sleep, but as we move into the second half of the night now that ratio balance changes and instead we have sleep with much more rapid eye movements and very little deep sleep, so when people think okay, I just go to sleep, I lose consciousness, my brain is still First of all, nothing could be further from the truth.

The case in terms of your sleep, second, your sleep has a very specific pattern that has real life consequences, so let's say you are someone who normally gives yourself a chance to sleep 8 hours in bed, but the next morning , based on what I've just told you that you say "Okay, well, I want to." I'm going to start the day off strong or have an early morning flight, so I'm just going to come up with numbers here. I'm not suggesting that this is the ideal sleep schedule in any way, but to simplify the numbers, let's say that someone normally goes to bed at midnight and wakes up at 8: then, there is the opportunity for 8 hours, but today they will wake up at 6:00 am. instead of 8:00 a.m. m.

To receive this boost in the day, how much sleep have you lost? Well technically they have lost 2 hours out of 8 hours so they have lost 25% but that is not entirely true, they may have lost 25% of their total sleep but due to the strange structure of deep sleep first and then REM sleep later, they may have lost 60 70 maybe 80% of their REM sleep, so I only raise this point because understanding how sleep is structured can have consequences. I'll go back to 90 minutes, although it's fascinating, we've heard it often and some people have probably heard this before it's a 90 minute cycle, well there's a lot of variability.

Some people may have an average sleep cycle of maybe 75 minutes, others 120 minutes, is this consistent within an individual? is relatively stable within an individual, so I would say that the size of the difference from one individual to another is much larger than the size of the difference within an individual from one night to the next, not much different from a cycle healthy menstrual cycle in for a woman, which can vary from a short period, you know, 24 days to 31 days, and it is still considered a healthy cycle that is regular, but it will change throughout life, of course, but for a good number of years it will be pretty constant within a given woman uh and yet between women it can vary quite a bit, yeah, and what's also interesting is that talking about some sex-specific things, there are sex differences, so on average men, if you look at them, will have a sleep cycle that's about 15 to 20 minutes longer than women, which on average 90 minutes is quite a lot and I bring this up because you may have seen some of those types of statements or devices, first of all, probably on social media and people send me these things. and let's say it's true, you really have to structure your wake up time in these 90'svery different minutes on the clock, when the clock strikes midnight 90 minutes, you know that is when you have to wake up and you must set your alarm right on these.

The rational thing, you will tell me that it is presumably wrong, but the foundation of those devices is that it would be better to wake up at the end of a 90 minute cycle rather than in the middle of a 90 minute cycle, even if it means sleeping less because the argument is that waking up at the end of a 90 minute cycle allows one to be more alert upon waking up. There is something

unique

ly special about completing a 90 minute cycle that will make you Ed without sleep, feeling like an Energizer bunny, those are some of the statements that they and if I had to ask now true or false false, so get as much sleep as you If you can, don't artificially end that dream based on anyone. telling you that there is this kind of Da Vinci Code magicUnfortunately, 90 minutes that's not true and you know I've been guilty of saying you know it's a 90 minute cycle and repeating it, so if I didn't know any better I would believe it, so I'm not trying to punish anyone.

I'm just saying be aware of that and don't worry, don't stress about this one 90 minute cycle and there are some products that say they will time you on your 90 minute cycle and wake you up. I'd probably stay away from some of those What about going back to sleep? You said I would get the most sleep possible if I slept for six hours and then woke up and felt like I could go back to sleep. Would it be better to go back to sleep whenever my work schedule allows? Or is it the case that after you've slept a certain amount of hours it's a good idea to get up and go?

I would say if you feel like there's even more sleep in you MH there is or I love that this has instantly become biographical it will be a good episode when that happens I would say hold your ground, stay in bed with an asterisk I'll come back to and see if you can go back to sleep and we can talk about different ways to help you do that, but the reason I put a slight asterisk is this: if you are then in bed for the next 45 to 50 minutes, wake up the danger and not It happens to everyone, but the danger is that you start to associate this thing called bed with this thing called wakefulness and not sleep and one of the things we do in the cognitive-behavioral field for insomnia is try to prevent you from spending long periods of awake time and I would say it's probably a general rule of thumb of 25 minutes.

It's not a rule, it's a general rule if after about 25 minutes you can't seem to figure it out and this happens a lot. it would just be aware of you and then you would start to build a bonded association in your brain that your bed is also the place to be awake. The analogy would be that you would never sit at the table expecting to be hungry, so why would you stay in bed waiting? be sleepy and the answer is that you shouldn't and that's why we have to break that association. Now there is nothing to stop you from saying that there is still sleep in me.

I know there is, so I'm just going to get out of bed. go to another room I'm just going to read a book listen to a podcast and then only when I'm sleepy I'm going to go back to bed because my schedule allows it that's the best way I would tell you yes I still think about the dream that's on the table for trying to get it back, that's immensely valuable, knowing that there's a kind of conditioned place effect of being awake in bed. I must say that I sleep pretty well most of the time. There have been phases. of life, even recently where sleeping has been a challenge and I notice that as I head towards bed to go to sleep recently, the words in my mind are here's the battle, Gra, like it's going to be a night of going to sleep, wake up, go to sleep, wake up.

We'll get to this sleep continuity thing a little bit later, so we don't have to get into that now, but I should also point out that some people, when I talk to them, they will and it's just because you mention it it's beautiful they'll say "I'm very surprised because I'm watching TV and I fall asleep on the couch and then I get into bed and I'm wide awake and I don't know why." and that's because, in part, you've built this connection in your brain and when you walk into the bedroom, that's what we try to do with cognitive behavioral therapy for insomnia.

You talked about it as a battlefield, it's almost a conflicting thing that somehow infers that at that moment you feel like your dream controls you and it's a miserable feeling and gradually over time what we would do is work with someone and at that moment Now you control your dream, your dream does not control you. and that's for your freedom when you receive it, but I'm sorry, I interrupted you oh no uh, I interrupted you but um, thank you, yeah. I have prided myself my entire life on being able to sleep anytime, anywhere. I learned that from my Bulldog Costello or maybe that's what brought us together because he certainly had that.

I am very sad that he is no longer here with us CU. I would have loved it. He feels that he is the best ambassador of the dream. If there is a post for the child to sleep well, well, he is here. in spirit, um, sleep, um, so this is interesting and I think it's important for people to know if you can't fall asleep or if you wake up in the middle of the night and can't get back to sleep quickly after about 20 Ones minutes it's probably best to get out of bed. So these 90 minutes are cycles that include different types of sleep.

It prompts me to ask you if you would describe the basic characteristics of each of those four stages of sleep and especially the three deepest stages. and four and REM sleep not just at the level of rapid eye movements during REM sleep but in terms of the types of dreams or the characteristics of the type of body state and you know, maybe you just develop the physiology and the neurochemistry and already You know, the touch. about the kind of sleep characteristics associated with each of these different stages of sleep, this becomes very exciting to me and even now, when I go to the laboratory where I look at the dream traces from my sleep center, I am still amazed, puzzled by what the brain does, as we start to fall into those lighter stages of sleep, once you get past stage one of sleep, which is almost the shallow zone where you're just wading, um, then you enter the stage. two dreams and one of the hallmarks of stage two non-rem sleep or something called sleep spindles and by the way, the way we measure sleep in a lab is we put you like a spaghetti monster, you have all of these electrodes. in your head you have things above your eyes and you have things in your body and essentially we are measuring three main signals, the electrical activity of the brain, we are measuring muscle activity and we are measuring eye movement activity and I explain why those three things They are necessary so that it knows if you are awake, if you are asleep, and if you are asleep, what stage of sleep you are in, so as we enter stage two of non-rem sleep, we have these sleep spindles. and at that moment I'm looking at the electrical signals from your brain, what we call EEG or electrogram, and these sleep spindles are these beautiful short synchronous bursts of electrical activity that last about one to two seconds, maybe a little bit. longer and they are exploding at what we call a frequency of between 12 and 15 Hertz and what that means is that these brain waves go up and down 12 to 15 times a second, that's our measurement of 12 to 15 Hertz and then you come back and your brain at that point has started to slow down now that we are awake your brain wave activity can go up and down maybe 20 30 40 times a second it is very fast and frenetic it is actually a very chaotic electrical brain activity but As As we enter these lighter stages of sleep, the brain begins to slow down and at that point, in stage two non-rem, it may go up and down only four to eight times a second, so there is a big slowdown in sleep. terms of brain wave activity, but Every once in a while you'll get these things that are going and then you'll get these beautiful bursts of these sleep spindles.

I actually never posted it publicly or we did a project called sonification of sleep and we took these. electrical signals and then we convert them into sound waves and you can actually hear this beautiful kind of this, it's almost this beautiful beat of a slowdown in your brain and then you'll hear these spindles that almost sound like that beautiful, delicious rolling R in Hindi. This is just wonderful I'm not sure I can do that R How are you doing? Yeah, it's not that bad, it's not that bad. I mean, we're on the feline side, but okay, Andrew, um, so, back to, I'm so.

Sorry, I'm going back to sleep, we've entered light stage two as I'm desperately trying to hold it together, and we're falling into deeper, non-deep sleep, now something spectacular happens and this is where I almost lose control. every time I see it, the brain now goes back down and its oscillation speed of going up and down is maybe only once or twice a second, it's incredibly slow and this is whole brain activity or localized activity so we'll see. Let's get to this first, the way we would measure it is simply from these electrodes that measure hundreds of thousands of brain cells underneath them, so a good analogy would be let's say you're in a football stadium and Stanford is playing Berkeley. in American football. and what we have is a single microphone hanging over the middle of the stadium and that microphone is picking up the combined voices of the 60,70,000 people below.

It's the same thing when we put an electrode on your head and you're measuring. the aggregated activity of hundreds of thousands of neurons underneath, but now we've started using maybe 100,200 electrodes on your head and we can pick them up in local territories of your brain, but those beautiful, powerful slow brain waves, um, that were being received during the depths. non-rm stages three and four is not just slow activity, you would think well, that sounds like the brain is inactive no, no, the brain at that point the size of the w waves is almost quadruple, maybe 10 times the size of the brain waves. when you're awake, why does that mean the brain waves go up and down very slowly, but the size of them, which is what we call the amplitude, which is now huge, is epic, so think about it, you're on the beach and when you're awake the waves come very very fast but they're small waves and they come randomly but the deep slow sleep are these kind of epic things that would happen in Hawaii where you just get these 20 30 foot waves and they come very slowly but they are epically big, that is, a deep sleep of slow waves and then what happens is that they ride on top of those big slow waves, they are these spindles of sleep that keep coming, according to the type of dream. sonification project what you would hear now these slow waves would be that that is the slow wave and the sleep spindle, what is happening in your brain?

However, to your question, to produce these slow waves, well, let's go back to the analogy of the football stadium before the In a game that is awake, everyone is having a different conversation in a different part of the stadium and you get this type of chatter. incoherent that happens when your brain is doing different things in different places in the brain processing different information. at different points in time and that's the rapid, frenetic activity of waking when you suddenly go into deep sleep for reasons we still don't fully understand, hundreds of thousands of brain cells in your cortex decide to coalesce into their singular voice. of shooting and everyone shoots together and everyone goes silent together, everyone shoots together, everyone goes silent together and that's what produces these huge powerful waves, so the analogy in the football stadium would be at this point now and I'll do it.

I'll meet your Stanford University, they're winning and the crowd is pumping and all of a sudden the Stamford crowd is chanting Berkeley Sucks, Burkle Sucks and everyone is joining in, the whole stadium screams at the same time and then goes silent. at the same time it is an epic display of coordinated neural activity in a way we don't see in any other state of the brain. It's phenomenal. Just in everything you answered to the question I was going to ask what is the pattern of brain activity that you just described occurs in a similar or identical way during any waking state and I think you just said that the answer doesn't make sense if I understand Right, this is a very, very specialized brain state,

unique

to sleep, unique to a specific portion of sleep and that begs the question of what is it doing, so it turns out that all of these stages that we'll describe as different stages of sleep do different things to your brain and your body at different times of the night and it's very understandable that people in some ways in the public will come to me and say, do you know how I can get deeper sleep or how I can get more REM sleep? and my question first of all is why do you want more REM sleep and they'll say, well, don't you? the good things and I will say well, it turns out thatThey are all important, you need them all, but we can continue.

I'll talk about the functions of non-rem sleep first and then I should probably unpack REM. sleep um and then it explains its functions, but as an overview, what we know is that during deep sleep you first change in terms of your body's nervous system to what we call the parasympathetic nervous system that you've talked about a lot before, which en This type of very inactive calming state of your body's nervous system, the sympathetic nervous system, which is very misnamed because it is not sympathetic at all, it is very irritating and activating and, when we are awake, it seems to be somewhat more dominant depending on the state in which you find yourself.

We're in a dream, but especially in deep sleep, we shift into this very strong parasympathetic inactive calm state that instigates along with other things, um, and we've shown that by the way we published an article probably about a year and a half ago. . that these slow waves and these sleep spindles and the coordination of them, how well they are coordinated, seems to instigate a signal to what we call your body's autonomic nervous system that carries both the sympathetic and sympathetic nervous systems within it. and forces you into a parasympathetic state, so these brain waves, one of the things they seem to be doing is transmitting a message to your body's nervous system to tell it to calm down. calm down, what then happens first what we see is your cardiovascular system decreases deep sleep, you could argue that's almost the best form of blood pressure medication you could ever want, it's beautiful, then something happens within your immune system , we begin to begin. to unravel this, but we still don't quite know why these slow, deep brain waves appear to be a trigger to instigate two things in your immune system: First, it stimulates the replenishment of weaponry in your immune arsenal so that you wake up to the day following. day and you're a more robust immune individual, so these are things like tea cells, natural killer cells that fix all that good stuff, but what's also interesting is that there's a more recent discovery, it's not just that your body has returned all this. armory instead and actually amplified it, but your body's sensitivity to those immune factors has also increased, so you've replenished the armory and made your body more sensitive to those immune signals and that's why you probably We will see it in later discussions.

Your immune system can start to noticeably deteriorate when you don't get enough sleep, so that's a second benefit of deep sleep, a brain wave pattern. The third benefit that we have realized is that it is very good at regulating your metabolism. system and specifically his ability to control his blood sugar and his blood glucose and if we selectively deprive him of just deep sleep and we can do that now very intelligently, it's not like I see him go into deep sleep and I go to his room. and I wake you up and then you go back to sleep and that's how we used to do it about 10 years ago, now we can use a very clever method where we play auditory tones in your brain, but they are at a level that won't wake you up, that's what It's called a wake subthreshold and we determine it and by playing those tones it forces the brain to re-emerge from deep sleep, so you will still be sleeping a total of 8 hours, but I will have selectively eliminated only your deep sleep and when I do that, sure enough, your ability to control your blood sugar, your ability to control your blood sugar, I should say, is pretty demonstrably affected and it's for at least two reasons: the initial one is that the pancreas, when it sees This increase in blood sugar level normally releases it. something called insulin and that insulin is a trigger for your body to start absorbing blood sugar so that we don't have this toxic or we don't maintain this toxic spike in blood sugar in your pancreas when you don't get enough sleep and specifically when If you don't get enough sleep, you don't release the right amount of insulin;

Even worse, what we discovered is that selectively depriving yourself of deep sleep means that with the little insulin that is released, your body's cells become less receptive to that insulin, thus not releasing enough of this chemical to say that They start absorbing the sugar in the blood and the cells they are designed to put a straw into the bloodstream and absorb the sugar in the blood and no longer respond to insulin, so on both sides of the sugar regulation equation in the blood you become imper and then I can give you an example up in the brain, one of the things we found and we will discuss is that deep sleep helps regulate learning in memory functions, helps start moving memories. around their brain and protect and shift them from short-term deep sleep to long-term deep sleep.

However, we have now discovered that it is essential to risk your Alzheimer's trajectory. It is during deep sleep when you have a cleaning system in the brain that begins to eliminate toxins. The proteins that build up during wakefulness and two of those toxic components are something we call beta ameloid and Tow protein, which are critical ingredients in the Alzheimer's disease brain equation, so you could certainly understand it based on that litany of things that I have just provided and those are just some of the effects of deep sleep. You can imagine that's what I want to get and that's what I need to optimize.

It is not true because there is REM sleep. I'd like to take a quick break and shout out to our sponsor ag1 ag1 is a probiotic vitamin and mineral drink that also contains adaptogens and is designed to meet all of your critical nutritional needs. I'm sure you've all heard me say that I've been taking ag1 since 2012. And in fact, that's true now, of course, I eat whole foods every day. I strive to obtain those foods primarily from unprocessed or minimally processed sources. However, I find it difficult to get enough servings of fruits and vegetables every day, so with ag1 I make sure I get enough vitamins, minerals, prebiotic fiber and other things that are normally found in fruits or vegetables and of course I still I make sure to eat fruits and vegetables and that way provide a kind of insurance that I'm getting enough of what I need.

Additionally, I need the adaptogens and other micronutrients in ag1 to really help buffer stress and ensure my body's cells, organs, and tissues get the things they need. People often ask me if they were going to take the Just One supplement, what would that supplement be? should be and I always answer ag1 if you want to try ag1 you can go to drink a1.com huberman to claim a special offer you will get five free travel packs plus a year supply of vitamin D3 K2 again that's drink a1. com huberman before we talk about REM sleep, what about stages one and two of sleep?

Are those just, kind of jogging to the Sprint, which are stages three and four of deep sleep, or if I were to stage the question, asking like an experiment, let's say I'm an undergraduate or graduate student in your lab. and I say, can we do an experiment where we selectively deprive people of stage one and stage two sleep only and then of course the question is what do you put in? Instead, there are plenty of other experiments one would have to do, but has that experiment ever been done? If so, what is the consequence of being deprived of stage one two, rather than just being deprived of deep sleep, as you already are?

Um elegantly showed that stage one selective deprivation is very difficult because it's a de novo thing that you have to go through to get to the other stages of sleep. It is stage one, the stage of sleep that I and other people have experienced many times where you are falling. Asleep and um you start having a dream maybe about walking or running and then you drift away, that's fine, oh, and I should have explained to you what happens in stage one. I love it so as we get into stage one, obviously our eyelids are closed, but.

One of the first signs we know while recording. I told them that we are recording electrical activity in the head with these electrodes, but I also said that we are measuring the activity of IM movement and as they enter the light stage. one that is not RAM for reasons that, again, we have no idea why your eyeballs start to rotate in their sockets under your eyelids, that change that we can start to see we call slow eye movements and they are the hallmark of when enter the dream and if you are lucky enough to have a partner, you can see this, you can, you know, as they are falling asleep, you will see these strangers, now grant if they wake up, usually the relationship is over very quickly because the thing you are you the next time I'm around. a plane if the person next to me is sleeping I'm going to be the guy like you're a mirror yeah no don't do that I'm the only one who gets away with it cause I'm a card Carrying the sleep scientist and still, yeah, the American Alliance sometimes takes a bridge, but then you get these slow eye movements and the brain waves start slowing down again, but you mentioned something else and they're called Jer hypnogogic and like us.

Going into this first stage of sleep, I told you that the main stage we dream in is rapid eye movement sleep, that's not exactly true because everyone has had this experience where just as you're falling asleep you start having these little mini dreams. almost kind of a diet or light-on dreams and you, you can almost wake up based on the fracture point of cognition and what I mean is you're thinking, okay, so tomorrow I have to go to the studio that I'm interviewing. . that desperately annoying British guy M Walker and then there was the elephant in the room with a helicopter on the wings of his head and you almost think he wakes you up because you think wait, wait, sorry, sorry, come back, rewind what just happened . that's the point at which you've transitioned into what we call the hypnogogic state where you can have these hypnogogic dreams but you also have these JS.

We don't fully understand what's going on, but what we do understand is that like you. As you fall asleep, you begin to lose different aspects of your sensory perception apparatus, without losing the sense of where they went and cannot find them, but the processing of those now many will remain during sleep, one of the things that begin to degrade is what we call proprioception and you've talked about this before, which is knowing how your body is positioned in space, so proper reception is fascinating when you're walking with a colleague and crossing. on a street, have you ever had that feeling where you step off the sidewalk and you're chatting and all of a sudden you have one of those really bad wobbles where you can, oh, and it's because you had subconsciously calculated and computational? you understood where your foot was in space, you understood the force of speed with which it was descending towards the path below you, you had miscalculated the distance and your brain expected your foot to hit that path at a certain moment and it didn't. it sends an error signal to your spinal cord and that's where you understand that yes, this happened to me, um uh, last weekend I was at the San Francisco Zoo and periodically throughout the landscape of the San Francisco Zoo they have these kind of soft surfaces that are perfect with the concrete surrounding them, I think this is so that the kids can play on the various sculptures that are there and if they fall it's a little more forgiving, so I was walking on this thing talking to the person to my left and stepped. this surface now quite soft and suddenly I think I don't know how to walk on this thing and you know I've been walking for a long, long period of my life and I really had to pay attention and then and then you get back to the concrete and you can stop think about it for a moment and almost then you have to stop the conversation you were having because it takes control and you switch from proceptive to non-conscious and switch to the The problem is that when you are lying awake in bed, you feel the mattress underneath you , you feel the support you are receiving, all that feedback signal that was telling you was absent when you incorrectly calculated the distance to the road.

That's in place and your brain says everything's fine, but as we fall asleep, we start to lose that proprioceptive feedback. Normally, that loss of proper feedback and feeling of what is happening and where my body is before. loss of consciousness and then you lose consciousness and that's when the loss of self-reception occurs and you don't have this kind of mental panic that prevents you from breaking glass in an emergency, but sometimes the speed with which those things happenchanges and you start to lose proper receptive sensation before you completely lose Consciousness and at that moment your body says oh my God, the mattress just disappeared and I'm falling and that's where you can have these jugs, that's our best theory current.

I know we're going to talk a lot about dreams in a later episode of the series, but what you just told me forces me to ask right now whether or not it's possible in dreams where we feel like we're flying. Due to the absence of proception, we are as if we were on the mattress or whatever surface we sleep on, but according to the brain, we are suspended in space, right? Yes, then it is a possibility. why we have those experiences in some ways, although it takes us into REM sleep during REM sleep and I'll explain what happens in the brain, but what you're talking about is something that's even more unique to REM sleep as we go.

In REM sleep, your brain paralyzes your body, so you are physically locked in the imprisonment of your body. Why would your brain do this? This is what we call muscular atoni. I was telling you that we measure your brain electrical activity and we measure your eye movement. activity but we also measure your muscle activity, why do we do so well when you enter non-rem sleep? that muscle tone decreases but there is still some muscle tone there, but as you go into REM sleep, in fact, just a few seconds before you go into REM sleep. I already know that you will go into RAM sleep because when I hit you, you completely lose your muscles and if I had to choose you and I mean, I probably won't be able to take you out. from your bed um based on certain images that I've seen on social media um I'll do it, if I pick you up you would be like a rag doll you wouldn't have any muscle tone it's almost like those toys where it's like a donkey that sits down and has a button underneath and you press the whistle button and it just falls off I used to have them when I was a kid too, like the simple things that you and I had when we were kids and fate would still own a couple of these, but yeah, I need to get a donkey, one in any event um I know what you mean so this muscle and as we call the Aton muscle and I think in a kind of medicine usually with an a before it means the absence of something like if you have absence of arrhythmia of normal arrhythmia aasia yeah something like that or um and here it's aonia absence of tone in your muscles why would the brain do this right? the brain paralyzes your body so that your mind can dream safely you imagine how quickly you could get out of the G pool, if just like you described, you thought I can fly, so you get out of bed, go to the window and throw it , probably won't end well depending on what floor you're on, hence this lack of muscle tone.

The physical imprisonment that we have is one of the things that, by the way, defines REM sleep when you're awake, because if all I was doing in my sleep lab was recording your electrical brain activity and I was in the other room and I was just By looking at your brain waves as you enter REM sleep, I couldn't tell if you're in REM sleep or awake why, because the electrical activity of the brain is very similar when you're in REM sleep relative to when you're awake. and what that tells us is that REM sleep is an incredibly active brain condition that your brain is just turning on;

In fact, some parts of your brain may be up to 30% more active when you're in REM sleep than when you're awake. Impressive brain centers particularly emotional, so it's an amazing state of paradox and that's why we sometimes call it paradoxical sleep. Your body is completely immobilized, completely inactive, but your brain is fervent with its activity. By the way, people shouldn't worry when I. Let's say your muscles are turned off and what happens is that right before you go into REM sleep there is an explosive activity that will go up to your brain to light up your cortex, but there is another signal from the brain stem that is sent downwards.

All the way up the spinal cord to the alpha motor neurons in the spinal cord, which are essentially going to create this inhibition, are just the voluntary skeletal muscles, which means the involuntary muscles, for example, respiration, which helps you breathe. in the heart, that's the reason. We know we survive and live another day after sleeping, so don't worry too much about that, with two exceptions, although there are two sets of voluntary muscles for reasons we don't know yet that are stimulated by REM sleep paralysis. one of them is the extraocular muscles and that is the reason why when you go into REM sleep you can have these rapid horizontal movements back and forth, those should have been paralyzed as well, but they are not and interestingly there is a muscle in the internal environment.

Ear muscle that is not paralyzed and also contracts just like your eyes, but I'm getting into the weeds, so that's what's happening in these different physiological states and to your question, when you don't have any muscle tone. , maybe. That's an implicit part of the reason you can start having these absent gravitational pull dreams, which means you can start flying. It may also be the reason why, going back to proper reception, you can sometimes get that feeling that some people will do it. describe that my teeth always fall out I always feel that it is something very common or you feel the absence of clothes on your body and you say that I went out and went to this meeting and I realized that I didn't have any you put on your pants and you forget that Proception is also about knowing that you have clothes on and feeling those clothes, you and I can now direct our attention and feel those clothes on us, is it also true that when we talk about sleeping?

Speaking of falling asleep, the feeling that one is falling back into one's head, um, is it related to the progressive loss of self-reception in the early stages of sleep, or is it just semantics. No, I often think that may have been where it is. The notion comes from us, why wouldn't we say that I'm sometimes people say I'm falling asleep but or I'm about to fall asleep and we say I'm falling asleep now. Some of that may be because I'm falling into a sort of deeper and deeper state of a pattern of brain wave activity, perhaps, but I actually think at this point we don't ultimately know the origin of this, but I think which is imp pop because people have this sense of falling asleep like that.

I've found that if I sleep horizontally in a bed or on a couch, sleep is very different than if I fall asleep upright in a chair or partially upright in a recliner, yeah, um. For example, on an airplane, many other things happen on airplanes now. Bright lights, noises, etc., etc., so it's not a good experiment to compare those two situations: airplane recliner versus bed at night, too many variables, especially temperature, but are there any? evidence that the position of the body during sleep or the orientation of the feet in relation to the head, you know that the elevated angle up or down has some impact on the pattern of different stages of sleep or quality or any another aspect of sleep that exists There is a reason for this and we will probably get to this at some point when we talk about different methods to optimize sleep or the new wave of fascinating tools to improve sleep that have to do with temperature.

We believe that so you can fall. Falling asleep and staying asleep has to lower your brain and body temperature by a little less than about 1 degree Celsius or probably two two and a half degrees Fahrenheit and that's why you'll always find it easier to fall asleep. a room that is too cold than too hot because the room that is too cold at least takes you in the right temperature direction for good sleep, while the room that is too hot, on the contrary, turns out that the body's ability to dissipate heat is what We call thermoregulation. here and thermoregulation in one direction, which is the reduction of core body temperature, is superior when you're lying down versus when you're leaning versus when you're actually standing and it partly has to do with the distribution of blood through certain parts of the brain in distal versus proximal regions, that is, regions that are close to the center of your body versus regions that are further away, but the capacity of your body if we largely remove most of your clothing and then measure core body temperature and the way we do this um it's a delightful technique it's called a rectal probe and it's not necessarily nice for the experiment setup to do it and it's certainly not necessarily nice for the participant, but it's nice to put it on.

As an aside for a second, we can measure core body temperature and we can measure using temperature sensors throughout the body exactly what is happening with the blood flow and we can measure how the brain begins to dissipate heat because one of the main ways that We dissipate heat from our body is by moving blood around the body, when we bring blood to the center of our body, we trap it in the core and the core body temperature increases when we push that blood to the surface. to these fine capillaries and vessels on the surface of the skin and you start to dissipate that heat and you dissipate it more quickly, so your body's core temperature drops and the body's vasoactive ability to distribute that blood and then release that trapped heat . from the center of the body is higher when you are lying down and therefore your body temperature can drop more quickly, which is one of the many reasons why it is not as easy to fall asleep when you are at a 45° angle and why that your sleep quality won't be as good now, there are other reasons for just like you mentioned, but going back to position, I would say there are maybe at least two tests that would recommend positional differences or positional changes.

The first one is very obvious if you are someone who snores and you certainly have untreated sleep apnea, which is where not only are you snoring but you will be short of breath, that's what the word apnea means. another one with an a in front, pineapple, like you know you've heard about pneumonia and it's about breathing and apnea is about the absence of that breathing and with sleep apnea you don't just start to have an airway partially collapsing. and that's where that flapping occurs and that's the flapping sound that we're having, but then at some point you just hear silence and at that point the person stops breathing completely, shortness of breath, which is much more likely to happen if you are sleeping on your back because when you sleep on your back your airways are giving way to gravity, which wants to pull the airways down, close them and turn them off, so one of the suggestions for people who snore or have sleep apne is to try it.

Do your best to train yourself not to sleep on your back, there are now many devices that can help and ways to do it, just like we did in the old school. Sleep apne is more common in men than in men. "It's in women, but women still have it, but if you had a man, you would take him to the clinic and say, 'could you?'" and often it's the men who maybe have excessive body weight and so Therefore, they are larger in size. Tell me, can you also bring a t-shirt of your wife? It has to be a T-shirt that has a pocket in the front and then we would ask them to wear the T-shirt inside out so that it is a very tight T-shirt that is inside out and then you take a tennis ball or a hockey ball in the back pocket and While you are lying in bed and rolling over on your back you receive this painful signal from the tennis ball. pushing you back and slowly I know who came up with this is this Matt was this um Matt Walker idea this isn't me I'm not it's smart yeah I should be on social media now I should change to sleep torturer instead of sleeping Diplomat um so that's a recommendation try to be clear if you ask me there are certain positions we should stay away from in that circumstance yes that would be the other one go back to something I mentioned during deep sleep when this cleanse The system starts to kick into gear in your brain and removes these toxins from the day we've found a little bit of evidence and we and the Royal we because like you, my lab doesn't do animal research, we just do. research in humans, but some animal researchers had discovered that when animals sleep with their heads on their side, the brain's cleaning ability is greater than when the animal sleeps on its back or back, and in fact, if you look and see Me I would love this project if you go to Google and just search for sleeping animals, look at the position of the head and I guarantee that many of them, if they are naturalistic, are animals with their heads turned to the side, now the cutest ones.

The funny ones are when you know that a kittenhe has SPL on his back and his head is back, that's how someone with sleep apne would sleep on his back, but that's very rare, we almost never see it, so it's very interesting and what I found was that when those heads were in those kind of side positions, the brain's clearing mechanism was a little bit better, it wasn't night or day, it's not like, oh my gosh, I had the dream of sleeping on my front and you know. I'm not doing any brain cleansing or sleeping on my back and no.

I'm not saying there's no need to take it to the extreme, but I don't think there's any good evidence yet in humans that that's the case in the first place, and it's not the case either. There is strong enough evidence to make recommendations, but I mention it simply because it's in the data and it's starting to emerge that if you asked me about sleeping position and if there were any recommendations, those are the two descriptive tips I would give. It's not prescriptive advice, you mentioned the relationship between temperature and sleep and we're going to get into that in some detail a little bit later because it's very critical, but before we started recording this episode we were talking a little bit about yawning and I You said something really fascinating about yawning, which is that there are at least four competing theories about yawning that we have and I think there's probably a clear winner emerging, the first theory was that it was just tiredness that yawning is simply a sign that you're tired and it turns out that that's not true because a lot of people can yawn when they're bored and they're not tired and they've rested very well so that doesn't seem to be true, the next one was one that seems very logical and it's about trying to rebalance the blood gases and specifically oxygen and carbon dioxide, and you would think that maybe when you yawn with those types of inhalations huge volume of oxygen what you are trying to do is pump the oxygen back into your bloodstream or when you exhale maybe it involves exhaling more carbon dioxide, not unlike the physiological size that occurs during sleep of a double inhalation with a long exhale correctly or that one can voluntarily generate for anxiety management in the waking state exactly And and that was a theory that maybe you're trying to balance these blood gases and there were some very clever experiments where they took individuals and artificially increased their oxygen levels, but more specifically increased their carbon dioxide levels directionally, tried to manipulate it and asked if those individuals started yawning more because the idea would be if the oxygen in the blood is going down and the carbon dioxide is starting.

To add to that, if this theory is correct, you should start yawning more frequently and it made no difference, that's probably also why you don't see people yawning on a treadmill or when they have a higher oxygen debt. and older. carbon dioxide levels, so that theory was discarded, the third theory was one of contagion and it's fascinating to yawn how several other things have a contagious element, so the audience unexpectedly didn't know what you were going to say and before You said it, you said you told us something interesting and you did it. I guarantee there will be people listening right now who said, Oh, I just yawned in response to Andrew Hubman's yawn.

It is very contagious, partly it is the mirror neuron system and you. Obviously, we have understood this in depth, your brain has the ability to mirror the action states of other individuals, so a good example would be let's say I'm walking out the door, now I'm closing the door with my hand and suddenly , I'm going to catch my hand and you, across the room, are looking at my hand and as soon as I catch my hand and scream in pain, you almost grab your own hand, oh, because why, why, why You are doing it? which is not just because you know you are trying to be compassionate, no you have experienced some degree of what I just experienced, how it does because your brain has a system inside that reflects my action states and it is called a mirror system and you can imagine why it's very good to understand the actions and emotional states of others for prosocial abilities and all that good stuff, and one of the things that can also happen with this mirror neuron system is that it imitates. yawning so when you yawn my probability of yawning also increases because my mirror neuron system matches your Y and the interesting thing is that we know that other species also have a mirror neuron system and that means that when you yawn there is a statistically greater probability that your the dog yawns and it's a cross species, so when your dog yawns there's a higher chance that you yawn and we have this St and it's very clear that one of the other interesting theories is that when there are species that are cooperative species, for example a pride of life Lions when one of those Lions yawns first, many of the other Lions will yawn contagiously but then, consequently, there are a series of actions that happen after that contagious yawn and that is why some people have suggested that yawning is a way to enact cooperative group behavior, that's another theory, the final theory number four, which I think you have the best evidence for, is not the balance of gas exchange of carbon dioxide and oxygen, but when you inhale oxygen from outside, it is generally colder than the core temperature of your body and brain. and when we inhale there is a modest drop in brain temperature and when brain temperature starts to rise that is when we see the frequency of yawning start to increase, so next time you see someone yawn don't think that they are bored or it did not. get enough sleep, go up to them, hug them and say I know your brain is getting hot, it's okay and then at that point the friendship will end because no one should latch on and say your brain is hot.

I'm so sorry, but Anyway, other than that, um, I'm sorry, we took each other down, that um tributary of my contaminated stream of Consciousness, but that's a yawn, I explain those are the four theories and we don't have a definitive answer, but I think the best at the moment. will continue is that it is about cooling the brain, that theory makes a lot of sense. um people tend to yawn when they get tired, as you mentioned people can yawn for other reasons too, if I'm yawning because I'm tired and yawning is to cool down. Out of my brain being too hot is an attempt to put my brain to sleep because we need to cool it down to get it to sleep or something else is going on there too and this merges with the previous question about the body. position in which I have lectured at the university, you know, over a decade, as I know you have too, and occasionally, from time to time, there is a student.

I'm just kidding, there are multiple students, especially if it's an afternoon class or a very class. early morning class that they fall asleep in their chair and then their heads wake up with a start and we all know that keeping the room a little cooler sometimes helps keep people awake, unlike a warm classroom in the afternoon, but in some ways, what we're talking about here violates what you were talking about before that it's easier to fall asleep in a cool environment than in a warm environment. The brain needs to cool down to fall asleep, but then when we yawn, it's in response to the brain being too hot and then, um, and so I'm, I'm having a little circle for myself, yeah, help me understand the square, the square, that circle, I like it, yes, please square that circle for me, Matt, um, it turns out that for you to lower the core temperature of your body, the opposite has to happen, which is, you have to warm up to cool down and fall asleep and I mean warm up in a very specific way, you have to warm up the outer surface of your brain, you have to get blood to the surface of your skin and that surface almost acts like a snake charmer, the Dr. draws the blood hot from the core and pushes it towards the surface and you radiate the heat and as you radiate the heat, your core says.

Body temperatures plummet, so why would people fall asleep in an afternoon meeting when it starts to get a little warm? Well, part of it is because the heat in the room is starting to make the type of face a little pinker. bringing the blood to the surface, then what's happening is the core of your brain and the temperature of your body is starting to drop and at that point that's why you're going to start to feel a little sleepier, that's the reason you described the second one. It's that afternoon when you know you're in meetings around a table and you start to go crazy, like you said, those wonderful heads and people listening to you, you all know that where the head goes down and goes up again it's not that people are listening to good music and to do that kind of head shake is that they fall prey to what we know is a genetically pre-programmed dip in their evening alertness, it's called a postprandial dip in alertness and that infers that it's after some type of meal in the evening.

It turns out that it's not really related to a meal, people say, well, I had a heavy lunch, I had a kind of shepherd at lunch and I'm always sleepy afterwards, maybe partly, but if I eliminate it, you I prevent lunch and we have also done these studies. your brain still shows this very reliable drop and alertness somewhere between quite broad but between 1:00 and 4:00 p.m. In the afternoon, yes, for me it is always between 2:00 and 3:00 p.m. which is a time where I'm resisting looking at my watch right now just to see, yeah, we could be in that phase of the day, I can always feel it and, if I close my eyes for 10 or 20 minutes, that Usually, I can fall asleep pretty quickly, yeah, for a nap.

I know we'll talk about naps later, um, but if I don't do it and I hold it in, then you know, usually around 3:30. I'm fine, get up. go back, right? and it kind of sways upwards and that's part of the reason for the yawning and that warm feeling of being in the boardroom, the boardroom meeting and the blinds are open, the sun. It's coming, I have the sun on my back, I'm starting to get very hot, but I'm starting to get very sleepy, it's the connivance of two things, it's that you're entering this zone of sleep that is more frequent in the afternoon, this postprandial drop in the state of alert your brain and we can measure it, it's very reliable, you can see this drop in the electrical activity of your brain and it's heating up at the surface, which brings blood to the surface and releases that heat from the core. drops and boy do you want to fall asleep?

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I think we all know it. What is bad sleep when you can't sleep, but I think there's a whole different category of bad sleep that you're going to tell us about which is the dream that we think is good but it's actually not as good as we think. It's just that I am always the protagonist of Doom and Gloom, not good, but also, but also, the delivery of powerful tools to improve sleep and therefore the state of wakefulness, so that in that sense you know what it is for really the dream and what happens. when we don't sleep well it's maybe more intuitive for most people, you know, I feel in a bad mood or I can't remember things or just you know, stress seems to feel a little more intense, the same amount of stress feels more . intense um and what is a good dream, you know and and this is, I think everything under the umbrellaof, you know, why we sleep, I mean, why do we spend a good third of your know or more of our life in this incredible state? of mind and body that we call sleep and it really is a pretty amazing state of idiocy when you consider it because when you are asleep you are not finding a mate, you are not reproducing, you are not looking for food.

You are not caring for your young and, even worse, you are vulnerable to predation for any of those reasons, but especially all of them, since collective sleep should have been strongly selected in the course of evolution and, in fact, one of the founding fathers of the dream. Research Alan Re Shaen once said that if sleep does not serve an absolutely vital function, it is the biggest mistake the evolutionary process has ever made and now, what we have learned through more than 10,000 research studies in the last 70 to 80 years Now nature didn't make a spectacular mistake in creating this thing called sleep so maybe I can address first what sleep does and what happens if we don't get enough sleep and then the other question is what is good . sleep in terms of what sleep does and why he was right in saying that Mother Nature didn't make a mistake and hasn't, because if we step back, every species we've carefully studied to date seems to sleep and what that does. tells us, even you know, earthworms, very ancient, evolutionary, ancient, they seem to sleep, they will have a period of what we call theargus, which is that they seem to be inactive, so I mention that point because it means that sleep seems to be evolved. with life itself on this planet and then has heroically fought its way through every step along the evolutionary path and that alone should tell us that whatever the dream is doing, it should be non-negotiable life support and necessary.

How is life support necessary? Well, now we know a lot of those first ones when you're not getting enough sleep. I can talk about your hormonal systems. Let's say I take a group of really healthy young men and limit them to four or five hours of sleep for five nights. you have a similar testosterone level to someone who is probably 10 years older than them, so lack of sleep will hit you in 5 days after a decade. We also see imp uh imper equivalent in female reproductive health caused by lack of sleep impermanence. on estrogen, on follicle stimulating hormone and also on luteinizing hormone, what about the effects of a single night of bad sleep on hormones, and I won't go into too much detail here, but you need to have four or five nights minimum rest? sleep often before you start to see these effects or let's say someone sleeps well for three or four nights a week, but then the other three are a little bit challenging, for some reason, do you see a gradual effect, sort of a reduction in between ?

In sex steroid hormones, like testosterone, estrogen, follicular stimulation, there is some degree of dose-response curve, but we haven't mapped it out with high levels, so the way I would like to do it as a sleep scientist I would say : "It's ok, I'll do it". this for one night and I'm going to divide you into seven hours 6 hours 5 hours and then I'll do it for two nights and you'll be back to 6 hours 7 hours 4 hours and I would like to build this High Fidelity map and understand that we don't have that, but certainly what we know is that one night of total deprivation will noticeably alter those hormones and we know that after a work week of little sleep it shows. those imperfections too, but let me go back to one night, so that's the hormonal system as an example and we've already talked about or I'll come back to that right now, the metabolic system and another hormone, insulin, what we found is that if I take you from new and I limit you and you're perfectly normal and healthy you don't have any signs of type 2 diabetes and I limit you to let's say 5 hours of sleep for four nights and then I measure your ability to dispose of blood sugar and, um, your level of impairment Your blood sugar is so off that at that point your doctor would classify you as prediabetic, so I could take an individual and within five nights of short sleep I can get you down a path that is becoming very close to type 2 diabetes. and like I said, we have UND and Royal, we're here, every time I say we, by the way, it usually means that, well, every time I say I did something, I mean my center, we did something and when I say We did something, I want I mean, they did something that's fair Shand for attribution, and so there have been studies that have really broken down exactly how that impermanent blood sugar occurs and we mentioned that earlier in this episode I can also later. move on to, for example, your immune system.

This is a very good demonstration. First of all, there is a large study done by Michael ow and his colleagues at UCLA and they took healthy individuals and limited them to just four hours of sleep during a single night. and measured the levels of critical cancer-fighting immune cells called natural killer cells and what he found is that after that night of just 4 hours of sleep there was a 70% reduction in natural killer cell activity, which is a surprising state of immunity. deficiency and just to give people a point of reference, these natural killer cells are considered almost like the secret service agent of your immune system.

These natural killer cells are very good at identifying unwanted dangerous elements in your body, like cancer, and going after them and destroying them, so you want to have a very verile set of these immune killers in your body at all times and if you don't sleep you will. enough, that may not necessarily be the case, we also know that if you don't get enough sleep. in the week before getting the flu shot and this is just another example of how sleep is critical for your immune system, if you don't get enough sleep in the week before getting the flu shot, you produce less than 50% of the normal.

The antibody response, therefore, makes the flu vaccine largely ineffective in terms of vaccinating you. We also know that if you don't get enough sleep on average, let's say you sleep less than 6 hours or less on average, you sleep almost three. times more likely to develop the common cold, the common flu and I know that you, at the time we recorded this, have published some fantastic content on the flu and the rhino virus in particular, so it's a good demonstration of your system immunological. We also know that it's not just that it's also your cardiovascular system that suffers when you don't get enough sleep and here again the data I think is very strong cardiovascular disease, large RITs, including strokes and heart attacks, and there's a study that I think illustrates this and, granted now, in terms of replication, the effect sizes may not be that large, but the study was interesting, they didn't do something radical like deprive you of sleep for an entire night or limit you to 5 hours. of sleep for, you know, four nights, there's a global sleep experiment that's been done on about 1.65 billion people in 70 countries twice a year and it's called daylight saving time now in the spring, when we lose one hour of sleep, what they looked at in that paper showed a 24% relative increase in heart attack risk the next day, but in the fall, when you gain an hour of sleep, there was a surprising 21% reduction in the heart, so it's two-way and by the way, I said that article.

There are some aspects that can be argued, but it has been replicated: we see higher hospitalization rates after that hour of sleep loss in the spring, there are higher rates of car accidents on the road after 1 hour of sleep loss. While we sleep, we also see higher rates of suicide after 1 hour of sleep loss during the spring time change. Even we see that this is excellent data. They analyzed the rulings of federal judges in the United States and because it is the federal system, the government system. of those things are cataloged and well documented, you have a huge database and they came back and what they found is that in the spring, when we all lose that opportunity to get 1 hour of sleep, those judges imposed harsher federal sentences the day after we had lost an hour of sleep because his emotional and mood states were undisturbed and we'll talk about this too in a later episode, so if you're ready to be sentenced or try to avoid that spring time change as best you can, go for the date of autumn if possible um then that's your cardiovascular system.

I could also tell you that it goes down to the cellular and molecular state of your body and this. I'm trying to do this to emphasize the fundamental importance of sleep. There was a wonderful study done by my colleagues at the University of Sur in the UK, led by Duk Yandy, and what they showed was that if you take healthy individuals and they will all act as their own control and you limit them to um. 6 hours of sleep for a week versus allowing them to sleep at least 8 and a half hours or more in bed and then what they did was they measured the change in their gene activity profile relative to when those same individuals, like I said, they were sleeping. a full shot at 8+ hours in bed versus the 6 hours of limited sleep and they found two interesting things first: a sizeable and significant 711 genes were distorted in their activity due to lack of sleep, by the way, that's relevant, we know that almost one in three, maybe even one in two, if you look at the data, people who pass you on the street try to survive by sleeping six hours or less during the week, so it's a relevant ecological manipulation.

The second result was that about half of those genes increased in activity, the other half would decrease. Now those genes that were affected by a week of short sleep were genes associated with the immune system, so once again you can see this immunodeficiency, but now it develops to a higher level. At the genetic level, those genes that were upregulated or what we call overexpressed were genes that were associated with tumor promotion, genes that were associated with long-term chronic inflammation within the body, and genes that were associated with cellular stress and , as a consequence, cardiovascular diseases and For me, that study impressed me with the fact that there is no aspect of your well-being that seems to be able to retreat from the sign of lack of sleep and emerge unscathed;

It's almost like a broken water pipe in your house where sleep will seep into every corner. and cracks in your physiology and will even alter the very DNA nucleic alphabet that explains your daily health narrative, so I paint this picture that looks dire and I think someone once told me look at your Ted Talk, which I think is was called Sleeping, uh, sleeping is your superpower, they said talking should have been sleeping, or dot dot dot, which was a completely fair thing to do because I think you've known that from the beginning, as a public Sleeper figure.

I did a terrible job. very dictator I very much disagreed um well, I think I think I was very absolutist and I learned my lesson. I disagree and and um and I'm going to intentionally interrupt uh so as not to blow you up. just because, but I think it's fair to say that I know it's fair to say that the cautionary notes that you talked about in those early TED talks and in your book Why We Sleep, although they may have stimulated some anxiety in some people, uh, it absolutely had and has a net positive effect in the sense that they pointed out to people the importance of this thing called sleep because before you did that or those things, it was the case that it was the "I'll sleep when I'm dead" mentality. um and as someone who has spent many sleepless nights in his career, many, many um, although not anymore these days, thank God, um, I can tell you that that information was transformative for my behavior and also for the people in the military sports arenas, children, adults.

It's fair to say that as a consequence we have better parents, better children, better citizens of each country, so I won't allow you one of the few things I will take a hard line on. I won't let you curse your contribution, and the good news is that this series will also include a lot of discussion about the things that one can do and anyone can do to improve their sleep, so yeah, enough of saying that I will, I'll stop trying. to reject that, but I would also like people to put the comments on YouTube, whether you agree with me or Matt, and then, you know, and thanks for agreeing with me, I would say please don't start.

As you mentioned there, you are making yourself anxious if you don't find it easy to fall asleep. Hear me out, first of all, it probably won't make things better, but don't think, even if you're in the general public, looking like that. I had a bad night's sleep, does that mean I'm now going to develop Alzheimer's disease? No, no, we're not suggesting that we're talking about a model where you know week after week, month after month, yes, I've demonstrated that. You know that after just one night of little sleep you can see deteriorationmeasurable and we can and I can't, you know I can't lie about the scientific data, but it's not as catastrophic as one might think and as you said In this series we will also talk and focus a lot on what you can do to start trying to optimize your sleep, so thank you for that opportunity, a lot of things happen that are not good for us when we don't get enough sleep in a day. constantly, yes, a bad night's sleep, let's face it, I mean our species would cease to exist if that were the case, because all these parents who have stayed up where you have an emergency or the neighbor's dog is barking or you go to an airb B where it's too hot and you can't sleep.

I mean, um, but clearly bad things start to happen when we're chronically sleep-deprived, we hear less often about the great things that happen when we sleep well, um, maybe I can talk about some of them, I mean, obviously, a lot of them will be the reverse of what you just described, but, for example, learning neuroplasticity, the ability of the nervous system to change in response to experience, lack of sleep affects learning, yeah, yeah, um and a good night Sleep makes it much easier to learn well, so what is the data in terms of the relationship between sleep and learning again?

Something we're going to go into in a lot more detail, but can you give us a um uh? Can you throw us a bone about some of the cans? Do you encourage us to sleep well not only out of fear but also because we hear the sounds? um you know, throw us a carrot, yeah, there are so many wonderful carrots, so when you sleep, your brain Its ability and its learning centers are much more prepared to absorb information, so think about these memory centers in the brain almost like a dry sponge if you've been sleeping well and are very excited to absorb new information and retain it in the first place.

Sleeping before learning will help you acquire and imprint new memories very effectively and we have proven that I will tell you about the studies in a later episode. We also know that sleeping after learning does something delicious. coined memories and it will consolidate them in the brain, which means that it will begin to fix them almost as if it were concretely placed in the brain, so you are much less likely to lose those memories, meaning you are much less likely to lose them . Forget if you have been sleeping after you have learned that it is not just that, although sleep does more than simply strengthen those individual memories, the dream will begin to interweave and connect those memories together and, as a consequence, the next day you will wake up and The memory catalog has now been updated with all the recent information and is integrated and associated, so you can now find new creative solutions to the problems you have faced because you updated what we call the associative networks in your brain and this is the which is why people will describe having had this knowledge through sleep and these problem-solving abilities and really that's what to me, a good student is not just a student who can learn all the facts written by the individual. and then just regurgitating them an individual memory isn't as sitting around as an isolated island isn't particularly useful, that's why your laptop isn't doing well as long as it's not connected to the internet and, uh, open AI isn't particularly smart, I mean , it has a storage capacity that is almost more perfect than your brain, it does not make some of the memory errors that we make, the reason it is not as intelligent as we are, is partly because it has not integrated the information, it doesn't link all the information, wouldn't it be wonderful if you woke up one day and installed a program on your computer and your computer understood how? all the files were interrelated and connected and it said, “Okay, you know you double-clicked this file.” Well, now I will tell you that there is this related information.

You should include it here and it would improve this. paragraph you're working on or would improve this experimental idea you're coming from doesn't do that but your brain does it, how does it do it? Partly it's because the dream is building these associative networks, so it's not like that. simply the student who learns the facts by heart is the student who learns the facts and then understands what they mean. Sleep is not just about learning and it is not just about knowledge, it is about wisdom, which is knowing what everything means when you fit it in and that's one of the other functions of sleep, so those are some of the beneficial things, like carrots that can help your learning and memory, there are many other carrots, although we describe for your immune system how this occurs. restoration.

That happens during deep sleep and prepares you for it, but there are other benefits too. One of the things that we've discovered and hopefully we'll be able to discuss this in more detail is that sleep provides almost a reset of your emotional state and mood. States and as a consequence you wake up the next day and you're dressed in a very different set of emotional clothing and when you're getting it you sleep it's almost like a set of emotional windshield wipers that just wipes away that stuff and you wake up. above is the reason why people will tell you you know if something is worrying you don't worry just come back tomorrow just give it a night's sleep and you'll probably feel better tomorrow that notion of feeling better is that sleep acts as an emotional bomb that just calms down that those jagged edges that we have, you know, they're almost like a CD that gets scratched if anyone knows what a CD is these days, but you know, these scratches that we get, emotional wounds, the dream is starting to cure them.

Plus, those are benefits. You could also mention some other aspects of your weight management and weight gain and this is a huge effect. Sleep moves the needle in almost every aspect of brain and body health. I think it's very clear at this stage. that there is not a single important tissue or physiological system in your body nor any operation of your mind that is not wonderfully enhanced by sleep when you get it or demonstrably imperfect when you do not get enough sleep, but when it comes to appetite and regulation of the increase weight is immense. First of all, what we know is that when you get enough sleep you can create a good concentration ratio of two hormones that regulate appetite called leptin and smile, and let me go more or less the other way around to probably give you better vision.

For example, let me tell you, I deprive you of sleep and what we see is that these two hormones, and I joke, you know sometimes they sound like leptin and smiling sounds like the Hobbits from The Lord of the Rings, but they're not, they're real hormones. and leptin essentially is the signal that tells your brain that okay, you're satiated with your food, you're full and you don't want to eat more, so hunger and appetite decrease. The smile does the opposite, when the smile increases, it is now the signal of hunger. and you feel increasingly dissatisfied despite eating a full meal, if you still have high levels of smiling, you don't feel satisfied with that meal and many people listening to you may start to say I have this feeling that I'm just eating and just I don't feel full some days and I suspect those days may be days when you don't sleep well and I think everyone has had that feeling of saying, "I didn't sleep well last night and I'm feeling hungry and it just unleashes this unholy hunger and an appetite that goes away." It's partly due to these two hormones.

So what happens is that when we don't get enough sleep, leptin, the signal that says you're satisfied with food, stops eating, which is insufficient due to lack of sleep. If that wasn't bad enough, the hormonal smile that says no, you're not satisfied with your food, eat more, that's the signal of increasing hunger, so it's almost like double jeopardy, you get punished twice for the same crime of not sleeping once. through a drop in leptin, stop eating and once, through a grunt of acceleration of the foot towards the floor, I want to start eating, that's partly why you're going to your waist can start expanding when you don't You don't get enough sleep, but when you do, it's a fantastic way to control.

I guarantee that if you start implementing better sleep, your ability to regulate your appetite and hunger levels will decrease, but it's not just that you want to eat less or at least want to eat. an amount appropriate for your body mass is also what you want to eat and what we have found is that when again you don't get enough sleep you start to eat more, yes you do, but you eat more specific things that you crave, like these heavy carbohydrates and heavy like bread, pasta, potatoes and pizza, and you also crave simple sugars, so those foods that we know too much can be what we call obesogenic foods, they are foods that can lead you to gain weight more quickly . whereas when you get enough sleep you're now reaching for the snack bar because you're saying what I think: salad and those healthy nuts and fruits and stuff look pretty appetizing today compared to when you haven't gotten as much sleep as you want.

What you need to do is go after the junk food and because you have these Munchies, the interesting thing is that a recent discovery came back to that notion of munchies. When I say I have munchies, people sometimes think of a drug reference and will say well. I've been smoking marijuana, I always feel like eating, why? Because when you put cannabis into the body and these cannabis, what we call exogenous cannabis, they will increase your appetite, they will stimulate your appetite, cannabinoids are components that stimulate appetite, but we all have our own version of cannaboids that we produce inside our body, of the one you talked about before, called endoc canabo.

When you don't sleep well, the brain releases more endoc canabo and that's part of the reason you get this strong boost and therefore IO when you start. you sleep better you moderate all these hormones and these chemicals and your appetite is controlled when you eat you feel satisfied with your food you do not have cravings anymore when you choose your foods you are choosing better foods we did a study with the brain Images in which we gave people little sleep and we had them look at foods inside a brain scanner and they had to rate, you know how much I want and how much I want these items and those items range from very healthy items to unhealthy items. items like ice cream and some kind of pizza and all those good and sweet things, um Candy, as you would say here, and we looked at their ratings and by the way, we made this more environmentally friendly because you could say Well, they're they're going to know what it is. the healthy option, so they'll probably be, you know, politically correct and say, oh, I want the healthy food, because the way we tried to avoid it was we said whatever you said was desirable when you come out of the scanner, in We actually have all these foods and you will have to eat them.

So they were doing more realistic things and each person did the experiment twice one night after sleeping a full night with significantly less sleep and sure enough, within the scanner they were rating the unhealthy foods as more desirable, so their preference was on that unhealthy direction, but what was interesting was what was happening in the brain: we saw that the frontal lobe regions are these kind of areas that sit above our eyes and almost act as the chief operating officer of the brain and help regulate our deep emotional centers, those regions of the brain that had been turned off by lack of sleep and these emotional centers that are generally associated with more honest reward and are also excessively more active in people with obesity who have what we call honest eating patterns, Those regions intensified due to lack of sleep, so it's not just that there are chemical changes in the body conspiring to make you eat more there.

There are also changes in your brain that prevent you from choosing healthy foods, but when you get enough sleep in the control condition, when they were sleeping, your brain beautifully regulated optimal food choices, so that's just another example of a trolley. carrot is not a pun now, um, that when you're sleeping, if one of the ways that you want to control your body composition and control your appetite is to get enough sleep, it's actually a very powerful tool that we probably underestimate and then This Another aspect, I would say, is emotional and mental well-being. Everyone knows that your emotional states and mood will sink like a dart into the ground when you don't get enough sleep.

It's that idea of ​​I just broke dot dot dot and those. are the words that you usually know are spoken by people who normally don't sleep very well, but when you sleep well it's much easier to regulate and manage those emotions and Michael Grand knows some excellent research on sleep. He did an interesting study and it was one of those studies that I read from my colleagues and my initial reaction to the study was jealousy because it was such a good study and I was jealous because it didn't.The idea came to me and now, gradually, with my advanced age.

I've disabused myself of that ego and very quickly think this is the best move and I can't wait to tweet it, but he did a great study and only recently asked what are the reasons why people want to try it. to improve sleep you would have thought we would have known about it decades ago and it is a relevant question to the point that you are asking what these carrots are all about. I know there's probably still some degree of sleep loss epidemic out there. In the world there is still that dream machismo mentality that I can sleep when I'm dead, so how can we try to motivate people?

I can do it with the stick and I can do all kinds of things, you know, if it bleeds. leads and does the doomsday stuff and that can be motivating, but why don't I try to understand what it would be like for most people who would try to adopt better sleep behaviors and they asked me for all kinds of different options and both? things at the end of the document when they did all the statistics that stood out like two sore thumbs I want to try to improve my sleep because I want to improve my mood I want to improve my sleep because I want to improve my body weight people know this, they already knew it, we didn't have to show you the data, so it's just interesting, so I just mention those two things as examples of carrots, there are many other, of course, examples of carrots too fantastic for that. one can achieve this if you get enough sleep and we will talk about quality and some other characteristics of sleep that are important in a moment, but I am curious to know how it is that when we are sleep deprived we have bags under our eyes and skin.

Health shows it like even one day you know if you know someone well and you see them regularly and they come in and they look particularly well rested, yeah, you know, we think it's, you know, bright eyed and bushy tailed, um. so to speak, but you can often see it in their skin and in their eyes, how glassy they are, how open they are, but also the bags under their eyes and of course people never say to anyone, you look tired, it's the other way to do it, it's only if they look particularly well rested on a given day, you say you look well rested, I actually told you that today you did, that's right, I would have forgotten about that, but now I remember and and It's true that you look very well rested being the sleep guy and all, why do we show our lack of sleep on our skin so quickly that it's almost like a thermometer that measures how much someone slept the night before?

Is awesome. You see it and you can almost see it, you know, if you have a partner and they come to that kind of kitchen in the morning and they look at you and because you are so familiar with that face because it is a face that has imprinted on you thousands of times you can notice subtle changes and sometimes you may feel like you know they look tired, but you're absolutely right, no, you don't say that, you just say, oh, you know, how are you this morning? Is there anything I can do for you? Should I make you a coffee?

Maybe you should go back to sleep and yeah, yeah, I think that's the politically incorrect roundabout way of saying boy, do you look tired? um, two things on that front, first. Going back to the immune system, that kind of paleness in the face, almost that sickly looking skin in PO, is because you are already seeing the effects of the immune system and the same goes for the bags under the eyes, which is part of this. human reboot, you know humans seem to have what I would describe as a recycling rate and it seems to be around 16 hours which after about 16 hours of wakefulness we need about 8 hours and it's 7 to n hours is the recommendation no.

Obsess over that, we'll talk about exactly that in a second, but it seems to be necessary to reset this whole panoply of health and physiology of a human being, one of the things is the immune system and you have this sickly look on people and you have bags underneath of the eyes, which partly explains that there was a great study done by a colleague of mine, Tina Sundelin, and she exercised in Sweden, at the Kolinska, and this again was one of those studies that I thought was so cool and it was a two-part study: first they took individuals and deprived them of sleep for one night or allowed them to get a good night's sleep, in fact, they did both and after a full study. night of sleep or after a night of sleep deprivation, they went to a studio and had the photograph taken, they did a portrait workshop in identical lighting conditions, so now for each participant in the study you have two head shots, one of when they were sleep deprived one when they slept they were resting very well now came the second part of the experiment, then they took all those kinds of headshots and they recruited a new group of participants who acted as an independent group of judges and those judges did not They knew nothing about the experimental conditions and the manipulations that had just happened, they were simply shown these pictures and asked to rate how attractive this person looks, how healthy this person looks, and how tired this person looks, and again They didn't know anything about what he was.

Indeed, with a very high statistical probability, when they took the headshot when they were not sleeping well, they rated that individual as less attractive, sicker in terms of their appearance and also more tired, so They had first demonstrated this. What's called restful sleep is that you look like a more attractive version of yourself when you get enough sleep, but you also noticed this sort of sickly composition on someone's face, so that's a long way to explain bags under your eyes. . Sorry, I'm coming. on these tangents Andrew and I didn't mention it at all. I asked him, he responded and um, and here we are good, so he's been explaining the different dimensions of sleep, the underlying physiology, some of the psychological and physiological consequences of not getting enough sleep.

Etc. I think a question that everyone asks is how much sleep should they get and B what is really good sleep and then of course there are all these other parameters of sleep that you know, leaving aside whether one sleeps or not, you already know a little. a little reclined or on your side Etc., you know, how should we think about this activity you call sleeping? How should we break it down? What are the variables that we should think about in terms of being able to ask ourselves how well or poorly we're doing it and for lack of a better way to say it to optimize our sleep, so I think about the question of what is good sleep at first, it seems obvious that you can talk to your partner again in the morning. and they'll say how did you sleep and you have an answer, you know, I slept well or I don't think I slept well, so we all have some subjective sense, but science for the most part, science and medicine have generally used it. a singular rubric that I think is reasonable, which is quantity, so you would hear that, okay, how much sleep do we need and what would that be like for good sleep and the answer is a quantitative answer somewhere between 7 and 9 hours?

In fact, I would answer differently if someone said: how much sleep does the average person need? I would say about 90 minutes more if you look, that's the answer you would give every yes, yes, how much sleep do I need and I would say probably about 90. minutes more if you look at the average data, but setting that 90 9 90 more um, if we go by the epidemiological studies of how much people are actually getting, but that quantity metric is the way most of us and I have been. No doubt, you are part of this too and have responded to the question of what is enough sleep or what would be a good amount of sleep and a good amount of sleep would be between 7 and n and that is the current recommendation of many health organizations.

Even here in the US, what does the CDC recommend or stipulate a minimum of 7 hours for the average adult? However, that doesn't capture the true complexity that the dream really is and is as we've discussed in the episode. a wonderfully complex ballet of physiology, so I took a step back and really tried to think about what are the main components that would make up this recipe for good sleep and conceptualized what I would describe as the four sleep macros that exist, you know, we thought about diet, that we have three macros, fat, protein and carbohydrates, for me, sleep actually has four macros and you can remember this by the acronym qqr and it means quantity, quality, regularity and timing qqr T. quantity quality regularity and time and maybe I can go into details because I'm telling you you know these are the rules for sleeping well no one responds to the rules they respond to reasons and not rules so let me explain the reasons behind each one.

Of these, we have already talked about the amount between 7 and 9 for the average adult. Let me move on to Quality, we measure quality in several different ways. The first principle of measurement of sleep quality is continuity, which means that your sleep was pleasant and continuous. and you didn't wake up many times or your sleep was fragmented and full of many Awakenings, it was punctuated by these Awakenings, if it is very fragmented, that is what we call poor sleep quality, low sleep efficiency, then maybe you would be in bed for Let's say 9 hours and you still had 7 hours of sleep, so if all you used was your measure of quantity, you would say well, you've still slept well, you've had 7 hours, but two of those hours were spent awake added up total, so it's very low sleep quality and it's what we would call a low efficiency score, so if you're looking at any of their sleep trackers, that's probably best captured by Sleep Efficiency.

What is sleep efficiency? Sleep efficiency is calculated simply from the total amount of time in bed, what percentage of that time will you sleep? So if you were in bed for 8 hours and slept 6 hours, you would have a sleep efficiency of 75% because two of the 8 hours are 25% of that time. I was awake and efficiency of 85% or higher we normally classify as healthy sleep and we'd like to see you there or maybe a little bit higher if you have a sleep efficiency score lower than that, it usually means you're awake. a lot of the time and we will think about it and address it, so that is a measure of the second Q of the qqr T which is quality, but there is another measure that we can also use, that measure goes back to the deep sleep that we talked about. and particularly the electrical quality of those brain waves, so you can have deep sleep and it can be of different qualities. electrical qualities, you can have a deep sleep that is immensely powerful with huge epic waves or you can have a deep sleep that is still classified as deep. sleep, but it's a little more anemic in its quality and you can't really measure that with these sleep trackers we have to use electrodes and then we break down the electrical activity of the brain using a fancy equation and that tells us what the amount of the type of activity force what we call electrical energy in that regiment of deep sleep, so that's another measure that we use for quality.

Next is regularity and in fact it should go back to quality. For a long time in sleep science we were using quantity as our main predictability metric, meaning I look at your quality and it predicts your learning or your memory. I look at your quantity and it predicts your blood sugar regulation. I observe your Quant Quanti. Does it predict your immune health? I look at your quantity. and it predicts your risk of mortality and the answer has been yes, the quantity predicts many of those things. That's great. The interesting thing is that if you look at the quantity predictability statistic alone, it was strong, it was significant, but it still left a lot of what we call variation unexplained, so it must be that there are other things in the dream that explain these health metrics, in addition to quantity and quality, which are now online.

I think in the last 10 years it has taken as much as yes. Maybe not even more so in certain domains of predictive strength in determining your physical and mental health than quantity has and at least forced me in my own research to always be me measuring quality at the highest resolution possible and always including it. in a statistical model and we can do fancy things where we put those two things you know, pit them head to head and see which one actually has more statistical weight, but certainly sleep quality is just as important, I would say now at least as important. important. like the amount of sleep now you can't shorten the change either you can't say well did you just tell me that I shouldn't worry about how long I'm going to sleep but about so long that you can't sleep only 4 hours?

You get incredibly good quality sleep and you get away with it, but you also can't be in bed for 9 hours or 10 hours sleeping 7 hours, but the sleep quality is really bad, you have to sleep both, you can't shortchange the shift either. . one of those, so at that point you think well, isn't that the end of the story? The QQ, why do you need this R and T of qqr t? Regularity has appeared online, I would say that in thelast 18 months as something relevant. metric when I say you, you would say you wait on a second regularity and synchronization, they sound the same when I say regularity, I mean when you go to bed and when you wake up, if you maintain that consistency, that is the third part of the four macros that is regularity I go to bed at the same time I wake up at the same time plus or minus how much, so I would say more or less you know, 30 minutes, that's your leeway, you don't want to try and everyone You know, even I'm very puritan about it to my dream, not because I want to be a kid and practice what I preach, it's just that if you knew everything I did about sleep, it's a completely selfish act to prioritize my dream.

I don't want to die sooner than I have to and I don't want to live with illness anymore, and the best health insurance policy I know of, which is universally available, largely free and almost painless, is this thing called night sleep, so I I will give it away every night. I don't see it as selfish because, of course, when we are sick or dead, there is a burden on others, it can be a burden of absence or a presence. load depending depending on what and how people, please look at me when you say presence over us, but that's interesting now when you say same time to wake up, same time to go to sleep, give or take 30 minutes for each of those, uh that's about 30 minutes uh to go to bed or we're talking about falling asleep going into the first stage it's actually from the moment the lights go out so okay I was in bed and you know , I got into bed at the same time, but last night I went to sleep about an hour later and then the night before, you know, I got into bed, I just turned off the lights and then two nights ago, I got into bed in bed again at the same time but then I was shopping online and started chatting with a friend in a different time zone and then it was 2 and a half hours before the lights went out, that's what we would classify as irregular sleep and the reason this was really thrust upon me as important was a big study that came out maybe I'm wrong about 5 months after the time of filming this ago and it used a huge database of something called the UK biobank, which is a wonderful database and they looked at over 60,000 people and it looked like they could track sleep from one night to the next, so they had some metric of this consistency, this regularity and then they divided those 60,000 individuals into quartiles and in the St statistical model they looked at people who were more regular versus people who were less regular and followed them for years, which they found and then looked at their mortality risk.

How likely were those people to die during that study interval and were you also able to map what they were dying of if they died? So what they found was that those people who are in the top quarter of being most regular relative to those people who are very irregular, if they slept well and regularly, had a 49% lower risk of relative mortality. for someone who was very irregular in that overall mortality risk, when you separate it out, there was a 35% decrease in cancer mortality specifically and there was almost a 60% cardiovascular mortality risk if you're regular versus irregular, so they did this Something brilliant because they were measuring both the amount of sleep and when these individuals slept they did what I just said, which is, they put them into a statistical model.

Indeed, the amount of sleep as we've shown time and time again was It's very predictive of all-cause mortality using that sweet spot of 7 to n hours and we can talk about what happens when you start getting more sleep because it's actually very unpredictable and it's very interesting, but the sweet spot of 7 to 9 the shorter the sleep, the shorter. your life, that's what the data seems to suggest, but what they found was that that was true, but regularity or irregular sleep had almost twice the size of the predictability magnitude effect that duration had and I think that Throughout the field we knew that regularity.

I knew that regularity. was important, I don't think we understood the importance and the strength of the mortality risk if you are regular or the higher risk if you are irregular that this R metric carries in the qqr T equation, so I started to be much more aware at least and almost about the index that, um, the final aspect has to do with time and I have to say that we have essentially used this type of equation, this sleep algorithm, if you will, qqr now in much of my work. in the past at the Sleep Center over the last four or five years and it seems to be a pretty good indicator to cover a lot of predictive aspects of your health that if you use any of these on their own, yeah, they help predict things. but if you use them as a collective, that seems to be where you explain most of the variation, now it's by no means a perfect measure, there are even more nuanced ways you'd want to split it and I want to split it, but I would .

Let's say this is a pretty good indicator for the general public, and in our research, it seems to be a pretty good indicator for health and well-being as well. The final aspect of qqr quantity quality regularity refers to time in which time differs from regularity because regularity is about sleeping at the same correct time. What I mean by time is your chronotype, so people may have heard of this phrase. Are you a morning and evening type or somewhere in between? Turns out it's about a third split. In the entire population, maybe a little differently, is it divided differently according to men and women?

And here I am, presumably we're not talking about children or teenagers, that's a completely different matter and we'll talk about that, yeah, yeah, so once you're an adult and that's because your sleep schedule pattern changes a lot during development, so even though you know, we can all remember when we were kids and we wanted to stay up with the adults and all of a sudden, the last thing we remember, you know, 7:00 is coming? 8:00 comes around and you think that's great, let's stay up until 10:00 or 11:00 with them and then you wake up the next morning because they put you to bed.

Because she was off, so put that aside once you're an adult and have your stable groove in place. There is variability now in the science of sleep, we don't divide it into three categories, but into five extreme types of morning, type of morning, neutral. evening type extreme evening type could you repeat that again? extreme morning type so extreme so what qualifies as extreme morning type? and then they wake up and wake up very easily around 4:4:30am. in the morning and they're bright as a bunny, they're ready to go to the gym and I'm neutral, I just sit right in the middle, so I'm an 11 to 7:30 type of person, okay, maybe we could walk for the extreme morning type it's around 8 and they might wake up at, say, 4:4:30 and they'd be fine, um, the morning type, maybe they'd like to go to bed around 9:30 and then they wake up closer to 5:36, then you have a neutral like me and I would like to go to bed probably around 11: p.m. and I wake up around 7:30.

I try to give myself an 8 and a half hour period in bed um and then you get to the um the night owls um so you have the night type and then the extreme night type who finishes the 4 five of the night type maybe they would like to go to bed like to 12:31 and they probably wake up around 9 9:30 and then you have the extreme night type and they aren't ready to go to bed until maybe 2:30 3:00 a.m. and they're waking up, you know, mid-morning, so what's interesting about your chronotype and, by the way, people you can if you want to know your chronotype, if you want a practical suggestion?

Can you just go on the internet and look up something called just write chronotype meq and that means morning and evening questionnaire meq? Simply type chronotype meq and you will see that you can complete it. It takes 3 to 4 minutes, a series of questions and it will give you back a score and that will then group you into these different flavors and tell you, "okay, I've tried all of these and you're okay, and I hate to admit it, but if I had my preference, I would go to sleep at 8". 8:30 and I wake up at 4:30 or so, let me ask you this question because instead of asking the meq, there's just one question that I usually ask and I say, okay, Andrew, now I put you on a desert island, alone and only you. you don't have anything to wake you up no electricity or responsibilities or anything what time you think your body would like to go to sleep and wake up and I say this specifically because if I ask you what time you would like you to be You're still predisposed in your head for all the traps of society and this terrible towards morning types.

Do you think naturally that's probably the regiment you would do? Yes, great question. I would go to sleep somewhere between 90 and 120 minutes after sunset. Yes that's fine. That's why I was going to answer I'm an extreme morning type or a morning type. I can go to bed around 9:30, wake up at 5:00 feeling great, or go to sleep early at 8, 8:30, wake up at 4. : and I really want to get up and write and exercise now that's not it. the schedule I follow. I may start following that schedule that I've tried for various parts of my life, but I usually end up going to bed a little later. 10 10:30 wake up fine 6 6:30 and that's assuming there are no events in my life that are interrupting my sleep because then I'm really going to sleep in if I can and a lot of things to try to figure out but assuming everything is well in life um and in the room where I sleep um that's the spirit there you go, I would say go to sleep at 9 and wake up at um yeah, around 4:35 a.m.

It feels great, in fact, I always thought of It's a bit of an antidepressant feeling. I don't consider myself someone who is depressed, but I can get a little upset if I stay up until 11:30 12 and even wake up at 7:00. I don't feel at all well and when I go to bed early and get up early I feel very, very good, you do that all day long and the interesting thing about this is that it works both ways, so the discomfort that you are talking about also it happens in night guys who are forced to be unfriendly M types no I'm kidding just kidding just kidding I mean society is we are desperately biased towards morning guys and we punish and stigmatize evening guys as lazy or lazy people who just can't understand it. together, why can't they be at the gym, you know, at 6:00 a.m.? m.

And in the office at 9:30? What happens at 7:30? What's the matter? I'm laughing because I was weaned on the Academy and the late Ben Baris, who was my post-to advisor and then a colleague who unfortunately passed away in 2017, but he used to say that I don't do mornings. He now he was our department head at the time, but he just said I don't do mornings. but he arrived around 11:00 a.m. or noon but he stayed until 3:00 in the morning. I feel like there has been a cultural change. I feel like 10 years ago if you were the person who stayed late at the office or in the lab.

You were considered a hard worker, true, but arriving early back then doesn't seem to be as rewarded nowadays, maybe something has just changed in my world, but I feel like the person who arrives first gets the prize in terms of a credential. psychological, yeah, I think there's this reward bias that goes on, it's this notion, you know, the early bird catches the worm, so I think we're desperately cruel. Society is designed for morning types, it's designed against evening types, the reason that's not fair is that and I'll go back to timing again and how it works and why it's important and the fourth ingredient, the fourth macro, but when we get there to the chronotype, the reason it's unfair is that it's not your fault that your chronotype is largely genetically dictated and we now understand that there are at least 22 different genes that increase your chronotype and that determine your chronotype;

In other words, it's given to you at birth, it's programmed and it's not your fault, but we still have this stigma and this. I think it's embarrassing, you know, not just belittled, but almost this kind of Ry appearance. Night types are a certain type and are not viewed very favorably, so think of it this way, you would never think of another trait, eye color, which you know, is genetically determined. and if you looked at me and said oh, he has blue eyes, you know, um, it's just that you're a little lazy because you have blue eyes, oh, you have green eyes, god, that's wonderful, that's well done, congratulations, wait a minute . second, it wasn't me, I didn't have the option, it's genetic, it was the same with your chronotype, but going back to why I, I included it in this type of algorithm of what it is to sleep well if I took an extreme type of morning and the force to stay up until midnight they will be incredibly tired, they will be very tired and they will be grumpy and miserable and they will have no problem falling asleep.sleep, the problem, however, is that they are still going to because of their C, their natural chronotype that determines their cadian rhythm, so everyone has this 24-hour circadian rhythm, as you know, you have been a wonderful advocate of that and you've done incredible work in this area, we all have this 24 hour rhythm. and it looks like a sine wave that sort of goes up and we as a dial species were active and awake during the day and then there's this incredible dip at night and we're inactive at night and it goes on and on and on, it's just 24 hours. cycle everyone has that, so why doesn't everyone fit into the same sleep chronotype model if we all have a 24 hour clock?

Well, the difference is that where that peak and trough are located on the 24-hour clock face varies by one. from one individual to another and that is what we call chronotype, so this leads us to explain why the morning type is important, they are in all their impressive fall of the Cadia rhythm at midnight and they feel miserable, they are desperate for sleep and when you put They put them in bed at midnight 4 hours later than they would otherwise they would be gone. The problem is that their cadian rhythm now starts to rise again around 4:30 in the morning and even though they went to bed at midnight, they will probably wake up.

They wake up artificially before completing 8 hours or 7 to 9 hours and go to sleep little at the end of sleep. This happens to me many times. I want to go to bed around 8:30 or 9, but for social or work reasons. reasons why I stay up until 11:30 or 12. I fall asleep very easily, yes, I have almost always fallen asleep easily and then at 3:34 in the morning I am awake and you can't understand it, it's almost like You would tell me that I tend to do this yoga. NRA deep rest without sleep and sometimes I can fall back asleep that way, but many times it is a struggle and I have been and it is a struggle because of your chronotype and your cadian rhythm which is on its wonderful ascending piston now apologies for the Motorsports reference, but I'm obsessed, yeah, I can't help it.

Sorry, Matt is a big F1 fan, as is Peter AA, so anyway, the incredible spike you're experiencing in your Cadian Rhythm is preventing you from getting any more sleep, but now come on. We reverse the table, let's take the type of night and I put them to bed at 9:00 p.m. or 10: p.m. when they normally won't be ready to sleep until 1am. and they're lying in bed and they're wide awake and they can't fall asleep and this is the main reason why night guys come to me and say look I think I have terrible insomnia.

I just had it and you know you can think of insomnia in a lot of different ways, but there can be two broad categories: one is that you have sleep onset insomnia. I can't sleep well. The second. "I have sleep maintenance insomnia, which is the kind of thing you were describing, which is where and you don't have it. I don't think you have insomnia, but I'll give you just as an example: you fall asleep quickly, but you can." Not falling asleep, that's maintenance insomnia, so they'll come to me with the opposite of your concern, which is they just say I can't fall asleep and I say, okay, let me ask you some questions and we'll go over the chronotype questionnaire and it's very clear that they are a nocturnal type and you know there are a lot of different things that you would want to exclude to make sure they don't have insomnia and then you can say that you don't actually have insomnia, you're just a nocturnal type and you're going to bed at the wrong time. and if you try to go to bed at midnight you won't suffer the problems you have and you will sleep in later, but of course their response is Well, I need to be at work at 8:00 a.m. m. and I have an hour commute so I have to be up at 6:30 so I need to be in bed at 10 so on both ends you can see that the morning guy who goes to bed too late falls asleep easily but can't fall asleep the evening guy who is forced to go to bed too early can't fall asleep but then they fall asleep and when the alarm goes off at 6:30 a.m. they don't want to wake up, so that's why when you sleep out of sync with your chronotype, things don't look good, so in those two circumstances, let's say I standardize it, everyone is going to go to bed at 1 p.m. and we got up at 6:00 a. m. and let's say we have a morning guy, not an extreme morning guy, who likes to go to bed around 9:45, they're going to sleep very well, it's very close to the natural rhythm. so I get extreme, even the guy who likes to go to bed at 2:am. and I make them sleep the same amount of opportunity 8 hours at the same time, well, surely they should be identical, they're not going to be.

It's not that they don't have the same opportunity, they do eight hours, it's just that one is placed on the inappropriate time of the 24-hour clock for the evening type but appropriate for the morning type and thus the quality of sleep that each one has is very different and therefore that you always need To incorporate a metric of what good sleep is, it's not just about quantity or quality or getting it regularly, but also about where you place your window of opportunity for sleep in that 24-hour clock to align with your chronotype when you fight against biology you normally lose and the way you know you have lost is illness and disease, that's why for me that final tea of ​​qqr t is so critical, that decompresses and explains this beautifully, yeah, beautiful and as you were finishing there, I was thinking that First of all, we have heard of Corona types or many of us have, but the way you described it makes it extremely clear why this almost has to be like this, because if We think of the extreme example of the untimely dream. which is shift work, you know, being awake at night and sleeping during the day, you know, basically, no one has that chronotype, yes, but people impose it on them and, by the way, thanks to the shift workers, the We need, you know, if I have appendicitis at 4:00 a.m. in the morning I am very grateful for the people who can help save my life, truck drivers, airline employees and so on, nurses, etc., parents who take care of children in the middle of the night, who work shifts, but I we know.

There are health problems associated with being nocturnal and sleeping that impairs the day, but of course there are a lot of other variables like the unavailability of sunlight if you sleep during the day and are awake at night, but I realized that there is no reason to think that one can change their sleep schedule by even a few hours and still get away with it; In other words, this notion of chronotypes makes a lot of sense, it's just that shift work is the most extreme example. of not being in sync with your with your with your chronotype, so I'm certainly going to do this chronotype test, but I'll tell you right now if I could sleep tonight at 9: and wake up at 4: that would be I feel so good.

I'm going to put you in my car. I'm going to make an intervention. You'll be in bed at 9:00 tonight. It is not negotiable. Fair enough, um, yeah, well, then we have to qrt. correct quantity quality regularity and time how do we know if we are getting enough sleep? and you know, this is something you know, you say between 7 and n hours. I heard well if you feel alert during the day, but maybe having just a little bit of that post-perennial dip is that I got it right, then you're probably fine, but presumably there are other ways to assess whether we're getting enough sleep or not, so there are certainly some ways we do it in science and clinically, but let's let that go for a second and just tell people listening what are some very easy tests.

I think the first test I would offer is if your alarm clock didn't ring tomorrow. In the morning you would sleep after your alarm clock and if the answer is yes, which it will be for many people, then you are not getting enough sleep. You don't know any other species. By the way, it artificially interrupts your sleep. It's very interesting, but we humans will do it. do it, let's wake up now. I told you regularity is key and I have an alarm clock. I usually wake up close to it or a little earlier, so I recommend an alarm clock, in fact, I would. argues that you should have two alarm clocks you should have one alarm clock with a tip and to wake yourself up most of us only use one alarm clock in the morning why don't we have it to tell us when it's time to go to bed so I have both so which I would say is good to use to keep you regular, but really, if you sleep past your alarm time, then you probably won't, you're not done sleeping, your body isn't done. with sleep and animals I would never do that so I think that's the first metric, another metric sometimes isn't as incredibly specific but have you ever been driving day after day after day and sometimes you think I don't know if that light was? red or green I just passed for inattention your driver um bite your tongue Walker bite your tongue so that's possible you may have been that's a potential concern in fact one of the ways we've developed a metric for the Dose response for sleep deprivation is to use concentration and alertness tests, in other words, if there is a breathalyzer for sleep deprivation, do these concentration tests.

Concentration tests are so sensitive that they are so predictive that it makes people just focus on a screen and go. to do a very basic stimulus response and you can do it for the first minute two with stimulus response um for those who don't know, it can be uh uh three letters appear on a screen and then you choose uh two keys uh you have access to two keys on a keyboard um if there are two similar letters you press the right key right if there is only one there are not two or more similar layers you press the left key simple simple things but we have to pay attention to a rule that is correct, you are simply doing a lot of different tests of different rules and it becomes monotonous, it's actually not very challenging, you have P ATT and that is perfectly imitated in some aspects, but we don't.

Don't do it for two or three minutes, we'll ask you to do it for 10 minutes and oh my God, it's numbing. I mean, it's a little fair, but it mimics very well, think about, you know, even a 1 hour road trip at 10:00 at night and you're on the highway, all you have to do is concentrate on the road and the white lies are coming and there is not much to do and you have to attend and concentrate not for 10 minutes, but for 60 minutes when you do not get enough sleep, one of the big dangerous problems of lack of sleep is that you don't know you're sleep deprived when you're sleep deprived and we know that because when I'm tracking your performance object it usually goes down and down but when I ask you subjectively how do you think you're doing in terms of your performance, you say: I'm holding on so far.

I'm fine, so you subjectively think. you're fine but objectively you're not the analogy would be a drunk driver in a bar you know they've had seven or eight beers they've had six drinks and they pick up the car keys and they say look I'm fine to drive home and your answer is no. I know you subjectively think you're okay to drive, but believe me objectively you're not. I'll just call you a taxi, don't worry, it's okay, it's the same way. with lack of sleep, so I emphasize going through traffic lights because you can have these attention lapses and these attention lapses are caused by microsleeps.

Microsleeps occur when the brain, very briefly, is almost like one of those toys. ducks that dip their beak in the water and then come back up and submerge their brain just drops and you have a quick sample of sleep and micro sleep and we can measure on your eyelid that your eyelid starts to have what's called partial closure and it just comes halfway or closes completely. It's a microsleep, even when it's half open. Your brain is essentially offline. He is in a dream-like state. We can measure it and then it comes back online. so I say that's a long way of saying that's the second metric I would use is do you have these absences where you just fail?

Another is that you mentioned it before I just don't feel recovered. um, you could say look, I sleep. probably about 7 and 3/4 hours a night, but I just don't, I don't feel awake, I don't feel refreshed, no, so can you operate without needing caffeine and have a good mood, a good mood, and good cognition? without needing caffeine before 11: a.m. in the morning and if the answer is no you may be self-medicating your state of insufficient sleep but that metric of saying I sleep 7 hours and 45 minutes that's what my sleep tracker says but it doesn't make you feel refreshed that it comes to the second Question about getting enough sleep.

I guess you would then look at your sleep quality and we would probably find a deficiency in your sleep quality, so there are these different types of tools that you can use. can use, but a good one is if you feel refreshed and restored when you sleep. It's not a guarantee of any of these, but to answer that question, do you feel refreshed and restored?when sleeping? Could we go a little deeper into some of the Outline of the day, so if I get a good night's sleep, which for me means going to bed early and waking up early, which tonight we're ABS, that's the plan.

I wake up pretty quickly. I'm alert upon waking up, maybe 5-10 minutes out of a semi-dazed state but sometimes I just have my eyelids open. I'm ready to go. Is it the latency from the moment of awakening to full alertness? It is a relevant metric. The other question is whether the postperennial or not. Drop is a relevant metric. We've already established that it's natural to feel a drop in energy at some point in the afternoon. I think you said between 1 and 4 p.m. 1 and 4 yes, yes, something like that. For me, that's true between 2:00 p.m. and 3:00 p.m. m. um, assuming everything else is equal, I just experienced that no matter what, um, but I imagine some people are really getting longer in the afternoon and would like to know if partial postpartum drooping is normal or a reflection of not getting enough sleep is There is some way we can drill down into these two hours of the day as a kind of measure to evaluate the duration and quality of sleep.

A little more beautiful questions. I would say that one should not necessarily take either. those two are your best metric, the reason is the waking component for some people like you, you are waking up and ready to get out the door, however many people will experience something called sleep inertia, which is almost this period fair. of time it's a bit like a sleep hangover the first hour I'm going to have to go back to the analogy of a car it's like a classic car engine where you don't just start it and you can rev it up and you know it just needs to warm it up gradually, increase the oil temperature and at that point after about an hour it will be at operating temperature and you'll be ready to go, that's the okay feeling.

I walk into the kitchen and kind of like your partner maybe looks at the dishes and I'm like, I know, honey, I know I said I was going to wash the dishes. I'm so sorry I forgot, but can I have my cup of coffee and I'll be the best version of? myself in about an hour, can we discuss it then? Because right now I'm not the best version of myself, that's sleep inertia and that's natural for a lot of people now, if you're a night type and you wake up early, you're going to leave. have a much heavier sleep inertial period than you would otherwise have, that's natural for you, but I wouldn't necessarily use that as a direct measure because a lot of people will have a sleep inertial period and if you do, you might worry if I say oh, it's The best measure is that you're not getting quality sleep after the initial dip, like you mentioned there before, even from the Monumental body called Andrew Hubman, even you can fall victim to that and fall sooner, so that's perfect .

In fact, I've learned to love it. I just love it, you know, here it comes and I'm fine, that's my circadian rhythm. We'll talk more about the circadian rhythm in a few minutes, but if I can just close my eyes for 10 to 15 minutes. in that perennial bathroom postp, so I really love it and you, yeah, I get out of that and we'll talk about how we were designed to sleep, maybe in a later episode two and whether that should be the way human beings sleep. so I wouldn't necessarily use that. I always have this post-criminal slump, does that mean I should worry about sleep?

I would say if you have excessive daytime sleepiness during the day where you're constantly tired and that's a term we use in sleep medicine is excessive daytime sleepiness or EDS, that should be cause for concern. I would use a slightly different metric of the same question, but at a different time of day, let's think about that Cadian rhythm again for most. people, even if you are a morning or evening type, around 11 a.m. m., around 11:00 a.m. m. noon, you are really starting to reach your Peak, you know that most people are somewhere on either side of the peak or around that Peak.

Say if you feel groggy and not alert and awake at 11:30 depending on your chronotype, I would probably use that as the best metric of my daytime sleepiness but by the way, that peak is very interesting if you look at it. c The peak when you are at your optimal level is both optimal for your brain and it is also optimal for your body. It is the point at which your body's core temperature begins to peak. That's the time when you have optimal physiology and when you look at world records. that have been broken in the Olympics and you trace them based on the time of day, you see this amazing beautiful Spike where most of the people are breaking world records right at that sweet spot of Cadia around that noon, Peri period, Why is it because that's the period where humans physiology seems to be at their optimal thermal temperature, at least it's fascinating, around 11:00 a.m. and 11:00 p.m. p.m.

Yeah, depending on what time someone goes to sleep and wakes up, right, yeah, and what time their chronotype is, and that's going to be very, but average because for me it would be my peak alertness and my physical ability, uh, performance. work, um, it's somewhere between 10: a. m. and noon, yeah, yeah, and that fits your brain and I guess if we took you to the gym and Can you follow your routine and see if we can do that routine once we have a set of basil metrics? I'll have you do it at 7am. m., then I will do it at 9:00 a.m. m., then I will do it at noon and then 300 p.m. then at 6 p.m. and then at 10 p.m. same workout, same human being, but there will be definite periods of time in the day when you are optimal and I suppose that optimization of the brain coincides with optimization of the body, so that your maximum performance and, let's say, your maximum height of jump or your maximum muscle strength would occur around those periods of time that fit with your own Cadian chronotype rhythmicity, which is why you've been talking about this 24-hour oscillation in sleep-wake activity called the circadian rhythm, such Maybe we can delve a little deeper into the circadian rhythm.

Do you know what it is? What can change it, if anything? And I'm especially curious about forces other than the circadian rhythm that impact sleepiness, sleep, and wakefulness, so the way we think about it in sleep science and there are some argue that maybe it's even more complex. than this, but for the most part there are two main forces, two main processes that will determine when you want to be awake and when you want to be asleep. The first one that we've talked about, which is your Cadian rhythm and that Cadian rhythm is um, you have a clock inside your brain, you have a central 24-hour clock and it's a master clock and that clock, as you've talked about many times, It's called the supermatic core, we don't have to obsess over the statement, just think of it as your 24-hour master clock and it beats this kind of rhythmic message of activity to us because we are targets during the day and then inactivity at night, activity during the day. and it just goes up and down, up and down every day, that's your Cadian rhythm and that's superism, the reason I say it's the master clock.

We have now learned that these cadian rhythm clocks exist in almost every cell in the body. You have clocks all over your body in these sort of small clocks, but a bit like Lord of the Rings, just as there is one ring to rule them all, there is one clock to rule them all and that is the central brain clock. In the supermatic core you can now dissociate those different clocks and you can make them do some weird things, but for the most part it's the central time giver, so you'd think that's all you need to tell your brain and your body to is the time. to sleep or it's time to be awake, it's not like that, there's a second force here and it's called proc or sometimes we call it s-process or sleep pressure, so you have your cadian rhythm on the one hand going up and down. every 24 hours, but then you have this funny thing called Sleep Pressure.

Sleep pressure is reduced to a chemical called adenosine, so from the moment you and I woke up this morning and we all listened, a chemical has been building up in your brain. That chemical is called adenosine and the more it builds up, the sleepier and sleepier you're going to get and after about 16 hours of being awake, there's enough of that sleepiness chemical that adenosine, um sleep pressure, by the way, It is a chemical pressure. It's not a mechanical pressure, you don't have to worry about your head exploding, uh, if you spend more than 16 hours a week, but that sleep pressure will start to weigh on your shoulders and you may feel that sensation where you start to think, ah , you're watching TV, you're starting to go down the hill and you think I should go to bed.

I'm tired now, that's because of one of two things happening first. We're reaching that crescendo peak of adenosine where it becomes so powerful that it knocks you over and you're ready to sleep, usually when you're in sync with your entire biology, these two forces, your cadian rhythm, which goes up and down every 24 hours, and your blood pressure. of dream they line up in this beautiful Ginger Rogers dance couple and are in harmony, the strange thing is that they know nothing about each other and they do not care about each other, one does not influence the other.

They are completely independent things, but let me explain it under normal circumstances and then I will describe to you a good example of how I can separate those two and show you that they are truly independent, so normally when we are in a kind of stable rhythm of sleep and wake activity , if we were awake during the day, we have this incredible surge of the Orcadian rhythm and then at night, let's take an example as they approach that kind of 8:00 p.m. rhythm. In this region your circadian rhythm finished its peak many hours ago and now it is beginning to descend and you are entering the steep phase of its downward movement type of its impressive downward movement, but also do not forget that at that moment your sleep pressure, your adenosine now you're also at your peak, you've been awake for almost 6 hours, so the time your cadian rhythm is in its nice downward swing and your highest adenosine levels in your sleep pressure, that's the time you it really will.

Determine well now is when I feel good and sleepy, so what happens? Then you go to sleep, you lower that curve of your cadian rhythm and you reach its Nader, its lowest point in the middle of your sleep phase, but also when you go away. to sleep that second sleep pressure factor, your brain has a chance to clear out that adenosine and it appears that a sleep period of about 7 to n hours is enough time for your brain to get rid of all that adenosine that's been building up. throughout the 16 hours of previous wakefulness and then these two things align beautifully again when it comes to your natural wake time, you've been asleep for, say, 7 and 1 half hours, you've flushed out all that adenosine, so that you no longer have the weight of that sleepiness pulling you down, but also your cadian rhythm is now at its incredible peak and when those two things align, when you have dissipated and discarded all that pressure of sleep and your cadian rhythm is starting to increase , that's the moment. when you would wake up naturally, so those are the things when they are working well and in alignment, let's say now I take you and I'm going to deprive you of sleep for 24 hours, so now we get to 10 p.m. your cadian rate is going down and your adenosine is starting to go up and around 2am. m. you probably won't be happy around 4am. m. or 5 a.m. m. you feel miserable why, because now you've been awake for, say, almost 20 hours straight, so you've got all this excess sleepiness, adenosine, pushing you down, screaming at you that you've been awake for 20 hours and your circadian rhythm is on point. lower, desperately wanting to get you into this thing called sleep and you feel terrible but then something strange happens at 11:00 in the morning in relation to, let's say, you know four, you've been awake for many more hours, so you've accumulated even more adenosine, so the prediction would be that if it's just the adenosine that makes the difference you should feel even worse at 11:00 a.m. you don't feel better despite being awake longer because your cadian rhythm has come to the rescue and now it's starting to increase and the distance between those two decreases and you feel a little more alert, but then as I get later in the day, around 6:00 p.m. 7:00 pm.

Now you are in your Cadian by Swit once again and you have been awake the longest and at that point there is almost nothing that can keep you awake, you will fall asleep standing up and with the toast, but that is a nice demonstration of how you can separate those two and even though one continues, you can start to feel better because the other has come to your rescue and that shows me that your Cadian Rhythm doesn't care how much adenosine is in your brain, it's just working. keep going up and down every 24 hours andyour Denine level doesn't really care much about your cadian rhythm it's just going to go up and up the longer you're awake and then it'll dissipate every time you sleep the clearance of adenosine uh I'm curious how that works um so this chemical adenosine is going away. accumulating in our brain, does it also accumulate in the body? um it does, but on the brain it has this very interesting influence now I've described it as making you sleepier and that's exactly what it does, but it does it in a very, very interesting way, it's a bidirectional way, there's at least two different adenosine receptors or adenosine welcome sites within the brain and Adenosine is very smart about how it makes you sleepy.

Adenosine, as it increases, will lower the volume of the wake-promoting regions of your brain, but it will still increase the volume of the sleep-promoting regions, and through this jewel action, that's what it looks like. instigates this drowsy feeling by tempering, slowing down wakefulness but stepping on the accelerator pedal during drowsiness, but then adenosine appears to be part or one of the reasons it builds up because it is a metabolic byproduct of the cellular activity of cellular metabolism ISM and It seems that the longer we are awake because our brain is very cerebrally active during the day, although I told you that the brain state of sleep is very active, it is a very metabolically active state of sleep, it is less metabolically active.

However, during deep non-r sleep, and it seems that deep non-r sleep is the main time when we become clear, we have the opportunity to eliminate adenosine. Now the clearance of adenosine happens all the time, it's just that the rate of accumulation when we're awake exceeds the rate at which we can clear it naturally, but when our brain goes into deep sleep it doesn't rem and becomes less metabolically active, it doesn't. is that there is necessarily a more active or very proactive state of deep sleep. that cleanse is not the same process of removing adenosine, it's just that there is no longer any buildup, so you have the opportunity to catch up on the day's adenosine buildup and then reduce that adenosine debt and then get to a net neutral net. in fact, in the morning, the amount of deep sleep, the quality of that deep sleep that you're having, specifically the electrical quality of your deep sleep, is a very good predictor of how well you dispel that sleepiness again, not that there is something special about it.

Non-rem sleep proactively does the cleansing faster than when we are awake, it's just that the accumulation rate when we are awake is greater than and exceeds the capacity of the cleansing, so it accumulates when we enter non-rem. less metabolically active now elimination exceeds accumulation and you can clear that debt. I have two more questions, the first is about growth hormone, so I was taught that growth hormone is mainly released during sleep, although there is some during the day as well. activities that can promote growth hormone release, as well as certain forms of exercise, perhaps some thermal stimulation, etc., but that the main event of growth hormone release occurs during sleep is true, although there is some argument that it depends on the dream. or just the dream coincides, okay, which means it's at the time of day, so is it a cadmium process where it's just at night?

Nur means either the growth hormone is released or it is night plus sleep that is needed and it seems to be a mix of both, but it seems to depend more on sleep than night and sleep. I probably should have said before that growth hormone is critically important for growth in children during development, but also for tissue repair and metabolism throughout life throughout life when we are adults, we need it critically, so if I understand correctly, when you go to sleep, growth hormone is released, but there is also a circadian component, so it's a bit of a gate, as they say, which is that you need this and that . to get growth hormone release and the reason I'm asking this, and I'm going to phrase it this way because I think it will clarify what you said and also lead to a practical step that has to do with sleep regularity and I've heard that the growth hormone surge is greatest at the beginning of the night's sleep and that if we go to bed a few hours later than usual we lose the opportunity to experience the same level of growth hormone release even if we sleep. the same total number of hours, so there is even more incentive for a regular sleep schedule.

Yes, then you are right, it is a door and therefore it is night. ESS helps, but sleeping helps, maybe significantly more, which means I can make you experience the night, but I. I can deprive you of sleep and selectively deep non-rem sleep and I can markedly alter your growth hormone release, but differently I think tell me if this is correct, but differently if someone has to work the night shift and sleeps during the day. they will still get a growth hormone release but not as much growth hormone release if they had slept properly at night so we can do it one of two ways so my way is to say I keep them on a marked nighttime schedule where You're awake during the day and asleep at night, but I'm going to selectively deprive you of just your deep sleep at night so that you stay asleep and keep getting through the night.ESS in bed, which is not the shift work version, but I can block or not block.

I can significantly reduce your growth hormone because I've selectively deprived you of sleep or I can do the opposite, which is the shift work approach, which is not going to deprive you of sleep, you're going to sleep during the day, but now I've kept sleep consistent. , so in my version I have kept the nighttime ESS constant and manipulated sleep. In your version, the shift worker, we have done the opposite. We've kept sleep consistent, they sleep during the day, but we've manipulated Ness at night and now, as you said yes, they will release some growth hormone even though that's not the natural time on the 24 hour clock. in which we would see growth. hormone released why because they're sleeping because it's a somewhat sleep-dependent process, but they're not necessarily going to release as much partly because they're not experiencing sleep in the nocturnal phases, so you can elegantly separate those two and that's why not It's neither one nor the other, but it seems to be both, it's certainly a sleep sensitivity.

I would say sleep sensitivity is a very good way to describe it. Okay, so translated into a workable protocol, everyone should strive to get an ideal night's sleep. Sufficient quality and quantity that you already talked about and getting enough, deep sleep will be especially important for the release of growth hormone. Right, my last question has to do with the other end of the sleep cycle, which is towards morning and towards morning. wake up, which is the hormone cortisol we hear so often these days about cortisol and people often frame it as bad, cortisol is bad, you hear this, that's just not true, they remove cortisol from an organism, they don't. they do, they won't do it right, right?

I need cortisol for immune system function to wake up for certain forms of memory formation, although too much cortisol is a bad thing, in fact, not having enough cortisol is an equally bad thing, so what is the relationship between cortisol and getting out of sleep? dream? And in other words, what is it? The relationship between deep sleep and the meaning of cortisol is sleep, a way we keep cortisol in check during stages of the 24-hour cycle when it would be detrimental to have elevated cortisol. Yes, it is and that's one of the ones I talked about and we'll come.

Moving on to this, maybe when we talk about emotional and mental health and when we don't sleep well, we go into a kind of more activated sympathetic, you know, agitated state of our nervous system, that's one aspect, but there's another aspect of the response. to stress. I mean, yes, you get an elevated heart rate, you're more sympathetic, which is this activated state as opposed to parasympathetic, but you also get, when you're sleep deprived, a greater release of the stress hormone axis, which is called the HPA axis, that if you really want it. To get into detail, it's the hypothalamic-pituitary-adrenal axis, which is a fancy way of saying that it's a signal from your brain that goes down to release cortisol, so that when you go into deep sleep you don't just go into the nice, calm resting state. of the nervous system, but you also get a dissipation in that stress-related axis and cortisol relief.

However, cortisol also seems to be under the strict control of your cadian rhythm, where it drops at night and, in fact, you have one of the steepest drops. the moment you start getting too sleepy, almost as if your brain and body know that we can't have cortisol even at the normative levels that you would have during the day because otherwise this person is still going to be a little too wired. M, this is the problem with a stressful event after, say, 8:00 p.m. m. of the night, if you see something stressful, you experience something stressful, I mean, if it's stressful enough, it will increase your cortisol at that late hour, it can really impede your entire sleep structure is one, I would say it's one of the things that I would recommend in terms of a good optimized sleep routine and we can get to that and avoid stress and arguments and TR and disturbing news and things like that as much as possible. as possible, yeah, um, late afternoon and early evening, even if you don't think you're necessarily someone who is sensitive to that, now I happen to be someone who is sensitive to that, it can really trigger me, so I stay Aside from that, we often see this with insomnia as well and we call it the tired but broad phenomenon and people will tell me look, I'm so tired, man, I'm so tired, but I'm so wired that I can't fall. asleep I'm desperate to sleep I know I want to sleep but I can't fall asleep because I'm too wide and that's a sympathetic state of hypercortisol and we can see it in your physiology, but back to your question, cortisol. it'll fall naturally throughout the night, but then it'll start to rise again and it'll start producing its fantastic sort of maximum climb speed right at the time when you'll naturally want to wake up again, so what we're mapping here is this wonderful tapestry. this kaleidoscope of coordinated biology that your adenosine levels are finally reaching their lowest point, your circadian rhythm is starting to increase, your cortisol levels are starting to increase, your core body temperature is starting to increase because it dropped along of the night, all of these things come together in this beneficial and simply brilliant synchronization ballet that naturally makes you wake up and feel like you're ready to go if everything is aligned if you have your chronotype right, your quantity of sleep, your quality, your regularity and your dream, you know it at the right time.

Well, your charm with sleep is really contagious. I have experienced it and I know that everyone listening and watching has experienced it, just as you have taken us on this truly spectacular journey through this phenomenon we call sleep. I mean, you informed us. Tell us what sleep is, what the different sleep cycles are, how they are structured and interrelated. You told us about the four macronutrients of good sleep, quantity, quality, regularity and timing. It's highly actionable information and then of course some of the hormonal, neurochemical interactions. and the consequences of sleeping well sleeping poorly for mental health, physical health and performance, so first I would like to extend a big thank you for taking us on this journey in the first of several or more episodes of this miniseries on sleep and I am We are very much looking forward to our discussion in the next episode about how to improve sleep and maybe even optimize it, so thank you very much Matt, on behalf of myself and the audience listening to me, I can't wait to continue the discussion.

I can't wait, thank you. you again for inviting me to this opportunity, by the way, what you do for the public in terms of your defense of science and also health, for what you do, thank you and for giving me this opportunity to be here to share the message of the dream. thank you, thank you so much for the kind words, it's a labor of love and it's a pleasure to be able to link arms to educate with you, thank you, thank you for joining me on today's episode with Dr. Matthew Walker to learn more about The Research of Dr.

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