Why Sleep Matters

Good night. Tonight we are gathered for the final Longwood Seminar of 2019. Welcome, I'm Gina Vild. I am the Associate Dean for Communications and External Relations at Harvard Medical School. And I'm delighted to see so many people here tonight. And tonight we're going to talk about

sleep

and why it's important. And I'm sure this is an important topic and concern for all of us because it is the most requested topic at Longwood Seminars each year. And so we're very excited to have been able to bring together three of Harvard's leading experts to talk to you about this tonight.

The issue affects us all because we know that without

sleep

our body and mind are not at their best. So raise your hand if you feel like you need more sleep in your life. We know why you are here. So tonight you will learn how to sleep better and longer. So, I first wanted to thank everyone who attended this year both in person and on our livestream. So if you've attended all four seminars this year, could you please raise your hand? Okay, fabulous, so I think we should give everyone a round of applause. And I would also like to applaud those who are watching via the Livestream.

You are among the 46,000 people who joined us and have been in this classroom this year for the first three seminars. That's pretty impressive. So, in addition to those of you here in Boston, we were joined by people from all over the world: from England, Canada, India, Australia, Brazil, Turkey, Pakistan, South Korea, and Egypt, among many other countries. So this is truly an international event that you are a part of. And if you missed any of this year's or previous years' seminars, we invite you to view them on our Harvard Medical School website. Before we begin, I would like to thank two members of our team tonight.

First, Lauren Gustafson, who makes sure these seminars are available to you through our social networks. And she's the one on Livestream who encourages you to ask questions. She's in the cabin. So she's not in front. But I want to thank her in particular because tonight is her birthday. And she chose to be with us. Happy birthday, Lauren, and thank you. And I would also like to thank Barbara Lynn. Barb, could you come up please? Many of you may know Barb because you had questions about Longwood Seminars. But she is the leader of this program. And you may not realize it, but her work for 2020 starts tomorrow.

So tomorrow he will start organizing the next seminars. And she has done an extraordinary job this year. So, Barbara, I want to thank you for your hard work, ingenuity, and passion for Longwood Seminars. Tomorrow Barbara will send you an email and I hope you all open it. It is a survey that will help us improve this program for the coming years and for the next one in particular. And one of the questions we will ask you is what topics you would like us to present on. And we took these suggestions very seriously and collaborated on the topics for the mini medical school.

So take a few minutes... that's all you'll need to take the survey. And if you're watching the live stream, we also invite you to send us your comments. This is the link for the survey: bit.ly/LWS_survey. And please take a minute and tell us what you would like to see and tell us how we did this year. So just a couple more announcements. For additional resources on sleep health or other health-related topics, visit the Harvard Health Publishing website: www.health.harvard.edu. And this is where you'll find a special health report on how to improve your sleep.

And for those of you who are Longwood Seminary students, it is offered as a discount if you use the code HMSLS. We offer certificates for those who attend three or more seminars. According to what I have been told, one hundred people have already obtained certificates. And after tonight, another 200 people will also qualify. So I'm really impressed by your commitment. And I honor your achievement. Thank you for being part of this program. If you have attended the first three seminars, you can collect your certificate at the back table. For those who qualify tonight, we will send them to you by mail or email.

And also, if you're a teacher, we offer professional development points for our teachers and many teachers joined us this year. We will be mailing those professional development points in the coming weeks. As you know, because many of you have been here to pass seminars, we answer your questions. And we try to reach as many of them as we can. Then our staff will walk up and down the hallways. Please pass your question to a member of our team. And if you're watching via the live stream, Lauren will ask you to post your question and note the country you're watching from in the comments section of YouTube or Facebook.

And we get to as many of those questions as possible. And so, for the last time this year, I'm going to ask you to turn off your phone, put it on mute, and don't turn it off because we hope you'll join us for a Twitter conversation at #HMSminimed. Now to our program. Here's what you may or may not know. About 70% of people do not get enough sleep and are sleep deprived. And this audience is representative, I think, judging by the show of hands for this statistic. 1/3 sleep six hours or less, twice as much as 50 years ago.

Then the world moves faster. We are running to keep up. And as a result, we sleep less. An estimated 50 to 70 million Americans suffer from chronic sleep disorders. The Centers for Disease Control and Prevention recently declared sleep disorders a public health epidemic. And research has found that lack of sleep reduces our ability to concentrate, think logically, and remember. So it is a very serious concern. And for that reason, we're so excited to feature three of Harvard's leading experts in sleep health. First, I would like to introduce you to Dr. Judith Owens. She is a professor of neurology at Harvard Medical School and director of Sleep Medicine at Boston Children's Hospital.

Dr. Robert Stickgold is an associate professor of psychiatry and the Center for Sleep and Cognition at Harvard Medical School and Beth Israel Deaconess Medical Center. And first, you'll hear from our moderator, Dr. Charles Czeisler. Dr. Czeisler is the Frank Baldino Junior Professor of Sleep Medicine and director of the division of sleep medicine at Harvard Medical School. He is chief of the division of circadian and sleep disorders in the departments of medicine and neurology at Brigham and Women's Hospital. And he is a nationally recognized expert in sleep medicine. So thank you for joining us and please join me in welcoming our speakers tonight.

Thank you very much Gina. And thanks to Ms. Berlin for organizing all of this. It's really exciting to be here. I'm going to encourage Dean Vild and Ms. Berlin, as they plan next year's program, to remember that we spend a third of our lives sleeping. So I hope that in the next few years you will dedicate a third of the program to something related to sleep. As Dean Vild mentioned, we are truly experiencing an epidemic of sleep deficiency in our society. And he mentions how many people suffer from sleep disorders and lack of sleep. And it's really causing problems in all ages of our society.

For example, children, over the last century, each year sleep about 1 and a half minutes less compared to the previous year. So today in the United States we sleep about two hours less per night than a century ago. Now, it is highly unlikely that during that period we have somehow evolved to need two hours less sleep per night for those children. Therefore, at all ages we carry the burden of lack of sleep. And it affects us in many, many ways. One of the things I like to think of as a barometer of the lack of sleep we have as a society is how many people struggle to stay awake when driving.

Thus, every month, about 56 million Americans admit that they have difficulty staying awake when driving. About 8 million of them lose that drug and fall asleep at the wheel. And that causes about a million accidents every year, 500,000 injuries every year, and about 55,000 of them are debilitating injuries that leave people quadriplegic or seriously injured in some way. And it causes almost 7,000 deaths each year. In fact, one in five car accidents is related in some way to lack of sleep. And so it really... It really represents a very serious problem. Maybe if I stay here, I'll be less trouble. So the question is why do we need sleep?

And sleep serves many different functions in the brain and body. It satisfies basic biological needs, especially in the brain. The brain uses more energy than any other part of the body. It is only 2% to 3% of the body's weight and yet it uses 20% to 30% of all the energy we use. Professor Stickgold will talk about the importance of sleep in our ability to remember things and in memory consolidation. Sleep is also essential so that we can maintain our focus, attention and alertness. So if children do not get enough sleep before arriving at school during the day, they will not be able to concentrate and pay attention in class.

One of the reasons there are so many drowsy driving accidents is that our ability to maintain our attention on a task, such as a well-learned routine task like driving, will be greatly impaired if we haven't gotten the sleep we need beforehand. . So our reaction time, instead of being a quarter of a second, for example, will be three, four, five or six seconds. And the average reaction time will be three times longer than if we are alert. And that can have real consequences. It can have consequences on all ends of the spectrum. Athletes, even the best professional athletes, their reaction time will be slower.

And they will have less...basketball teams will have less...players will make fewer free throws, tennis players will get fewer aces, and runners won't be as fast when they haven't gotten enough sleep. And also, as Professor Stickgold will talk about, the different stages of sleep are associated with the ability to integrate what we have learned with what we knew before and provide a fundamental function for that. But one of the other functions of sleep is, as I mentioned, there is a furnace that uses up all this energy in the brain, and it is during sleep that we replenish the energy that we have used during the day.

And one of the sensors that tells us the brain needs more sleep is actually located in brain cells. And it represents that as we begin to consume energy and deplete these energy reserves, some of the residual parts of the energy-related molecules accumulate in the brain. And we start to get tired and the brain starts to be able to make an involuntary transition from wakefulness to sleep. And of course, if that happens while you're driving, it can be very dangerous if you're fighting to stay awake and you lose that fight. And the late Professor Bob McCarley was the one who discovered that it is the levels of adenosine that build up in the brain that really make us sleepy.

And then, ironically, what many of us do to prevent that signal from coming is drink caffeine in one form or another. And caffeine is a blocker of that adenosine receptor. So it doesn't actually satisfy any of the biological needs for sleep, but it blocks the receptor. So we are less likely to make that transition unintentionally. But it doesn't prevent it completely. So think about that when you wake up and say: I can't function unless I have a cup of coffee. You would work better if you could actually get the sleep you need instead of covering up that situation with something that blocks the receptors.

It would be like... instead of turning on the heat when it's too cold in the house, you just put gum on the thermostat so you don't hear the fact that the signal that it's cold isn't being transmitted. fourth. And of course, if that is the solution, then it can lead to burst pipes and all sorts of other problems. Likewise, in the brain, if we don't get the sleep we need, we won't be able to fulfill some of the key biological functions of sleep. And you can see the changes in this diagram. You remember for a while that "this is your brain on drugs." It was advertised on television all the time.

Well, this is your brain without a night's sleep. And you can see very specific changes. So this is energy utilization. And you can see in the area of ​​the brain that is responsible for judgment, you can see that it is low on fuel. And that's why it's very cold there. And that's one of the reasons why people who don't get enough sleep often show poor judgment in the decisions they make. Additionally, this is the area of ​​the brain that transmits sensory information from our vision, touch, and other senses to other areas of the brain. And this is the area that receives visual information.

And we lose 10 times more signals in our visual field. And that's one of the reasonswhy we have accidents when we drive because we don't even see the things that are happening. Therefore, we are much more likely to miss things that are happening. That's why it's so dangerous to have, say, an air traffic controller who is responsible for seeing planes in the field of view from a monitor, because he won't be able to spot them as easily. And this is one of... now, another really key function of sleep that's been discovered recently is the removal of toxins from the brain.

So this high energy using organ, like anything else... like anything else that uses a lot of energy has some byproducts, metabolic byproducts of the energy that are essentially waste in the brain. It's like in your car, you start collecting sludge in the oil. And you have to change the oil and remove the sludge. Well, in the brain we accumulate toxic metabolites, such as amyloid beta protein and tau protein. And if we do not eliminate them, they can be toxic to the neurons of the brain. And that's one of the things that's associated, for example, with Alzheimer's disease: amyloid beta plaques.

And it is during sleep that these newly discovered lymphatic channels actually expand and remove these toxins when we sleep. And that turns out to be a critical function of sleep. And once this was discovered in 2012, it began to make people realize why there was an association with both sleep disorders and people with insufficient sleep having a higher risk of Alzheimer's disease and other brain diseases. degenerative. So one of the key functions of sleep is to help you maintain a healthy brain where these toxins are removed. Another key function of sleep is, and this has only been recognized in the last 20 years, that sleep is not only important for the brain, but it is also critically important for the body.

And that is why the cardiovascular system depends on sleep. It is during sleep that the heart can recover with lower blood pressure and lower heart rate that occurs during sleep and repair can take place during that time. And people who don't sleep, have disrupted sleep, or get enough sleep will start to have higher blood pressure. And sleep disorders, such as sleep breathing disorders, sleep apnea is the leading known cause of high blood pressure. That's why anyone diagnosed with high blood pressure should be evaluated to see if they have sleep-disordered breathing, for example. But even teenagers, if their sleep is disturbed, fragmented or insufficient, will have higher blood pressure than their peers.

Then they are on the path to hypertension. And sleep also turns out to be vitally important for our resilience and our resistance to infections. So the immune system is affected by the sleep we get. So in the fall, last fall, we were recommended to get a flu shot. And when people get the flu vaccine, if they haven't gotten enough sleep in the week before getting the flu shot, they have only half the antibody response as if they had gotten enough rest. Similarly, during the winter, if you are exposed to the rhino virus that causes the common cold, you will have a 2% to 300% higher risk of getting a cold if you don't get enough sleep or if your sleep is fragmented and disturbed.

Therefore, consolidating sleep and getting enough sleep are important for your immune system to function effectively. And that may be the reason... that may be one of the reasons why sleep fragmentation is associated with an increased risk of cancer and a higher rate of cancer and tumor growth, because the immune system is recognized to play a role. an increasingly important role. as we begin to understand it in cancer prevention. Now, sleep is also essential for regulating appetite. People often talk about freshman 15, which is a kind of weight gain that usually happens when kids start college. And that weight gain may be associated with the less sleep kids get when they go to college.

You see, somewhere during evolution, sleep and appetite became linked. And maybe it's because... it's not completely understood why that is, but most other animals don't spontaneously deprive themselves of sleep unless they're starving. And so, big cats, if they don't get enough food, will stay up for 24 or 48, even 72 hours, hunting. And during the time you deprive yourself of sleep to avoid starvation, your brain goes into starvation mode and releases more hormones that make you feel hungry and fewer hormones that make you feel satisfied with what you've eaten. The problem is that we voluntarily deprive ourselves of sleep when we are not starving at all.

In fact, many times we have the refrigerator right there. And then we deprive ourselves of sleep, we watch TV, we watch a game, we do this, we work the night shift or whatever we voluntarily do, and then we have a food source right there. So when these hormones are released that make us feel hungrier and less satisfied with what we've eaten, we're more likely to overeat when we're sleep deprived. And then people gain weight. And then one of the other surprising things that happens when people are sleep deprived is that, in terms of metabolism, the effectiveness of insulin is reduced and glucose levels increase by a greater amount in response to the same meal.

So now we find ourselves in a situation where people gain weight and the metabolic system's response to food is affected. And this puts many people in, and may be contributing to, the obesity and diabetes epidemic because of these metabolic changes. And because this increase in obesity and diabetes that has occurred in the last 20 to 40 years has been parallel to the decrease in sleep duration in our population and the increase in the problem of the epidemic of sleep deficiency in our society . And surprisingly, even fat cells need sleep. So if you do a fat cell biopsy on people who have been well rested and a fat cell biopsy on those same people when they've been chronically sleep deprived, the ability of those cells to respond and metabolize glucose is actually seen. affected in individuals, if They have been taken from people who suffer from chronic lack of sleep.

That's why the whole body is affected when we don't get enough sleep. And that's one of the reasons I'm going to argue that it's important to make sleep a priority. But it's not just about the brain and body, it's even about our emotions: we become much more volatile when we haven't gotten enough sleep. Increases the risk of depression, increases the risk of suicidal ideation and anxiety disorders. Our ability to avoid losing control when faced with an emotionally challenging situation is impaired because... and this has been studied here at Harvard Medical School using brain scans. The amygdala is a region of the brain responsible for emotional responsiveness.

And so, people in a scanner have been shown disturbing images and the reaction, the amygdala response, is 10 times greater in individuals who have lost a night of sleep compared to those same individuals who are calmer in their response. to these disturbing images if you have had enough sleep beforehand. So, it creates kind of a perfect storm for situations that we really wouldn't want to put our kids in. And so you can imagine my surprise when I took out our daughters who are now 24 years old. But when she went to pre-K, a couple of decades ago, as nervous parents, my wife and I went to pre-K school.

And we sat down. You know they make you sit in these little chairs. And for me, that's a bit of a challenge. So I'm sitting in these little chairs and the teacher... we all wanted to know how we prepare our kids to go to preschool. That's why she said the most important thing you can do to prepare your child for school is to make sure she gets enough sleep before she arrives. And you know I'm looking around to see if she had anything... did she realize that she spent my entire life sleeping? And I walked up to her and she said, I can tell within the first 10 minutes after the kids get here if you've been dragging them to the mall and keeping them up too late.

And she said I'll just call you on your cell phone and pick them up because I'm not going to deal with them if you haven't given them enough opportunities to sleep. So I walked up to her after her and said, have you been reading articles? Where did you find this information? She said no, I've been teaching for over a decade. And I know what it's like to deal with perfectly behaved kids if they've had enough sleep but our most complete cases if their parents have kept them awake before arriving... maybe they were on a flight, maybe they were this, whatever. .

To this day, I am stunned when I go to the mall or a Walmart or this or that at 10:00 or 11:00 at night and I see in these 24-hour stories people dragging their children, their small children. At one point I made the mistake of commenting to one of the parents: don't do that. But in any case, I was always drawn to the kindergarten teacher and what she said. And parents of very young children will often say Johnny or Susie: they are not themselves today. They're crying, they're restless, they're... because they didn't sleep last night. So parents realize that in the case of very young children.

Teachers realize this for 5, 6, and 7 year olds, but then somehow we think kids outgrow it. And they don't need sleep. But that is simply not true. The behavioral manifestations are more subtle, but equally serious. So today we have a situation where one in five children in high school is diagnosed with attention deficit hyperactivity disorder. Now, the symptoms of ADHD, the symptoms of sleep deficiency, can perfectly mask the symptoms of ADHD. So, the difficulty in focusing attention... we already see that this is one of the consequences of sleep deficiency. Emotional lability... that is another consequence of lack of sleep.

Difficulty keeping anger under control: another symptom of lack of sleep. So, yes, there are children with ADHD who need treatment. But there are many, many more children who don't actually have ADHD, but are misdiagnosed because they don't get enough sleep. And why can't it be that one in five high school kids has this relatively rare condition? Now, as I mentioned, there are so many different consequences of sleep deficiency, and I've only included a few of them on this slide. I've talked about the response to vaccination, our distraction, the increased risk of depression and suicidal ideation. Parents who don't set a 10:00 p.m. bedtime for their children in high school, they are children at significantly higher risk for depression and suicidal ideation.

Now, one thing that sometimes motivates children. I was bringing home a babysitter, and he was about 14 or 15 years old. He said what are you doing? And I said that I research sleep. And he said what a waste of time. I try to sleep as little as I can. And I said okay. I said that it is during sleep that you release the hormones that turn you from a boy to a man. And the following week he called me his mother and said: what did you say to my son? I said, what do you mean? She said, "Well, he's become the sleep czar." It's like mom turned off the radio.

I have to go to sleep. You're disturbing my sleep and so on. And sometimes we tell it... or I tell it to professional athletes. I say that if you sleep four hours a night for a week, you decrease your testosterone levels by an amount equivalent to 11 years of aging. And they say, well, maybe I should pay more attention to this. So let's talk a little about sleep disorders. And one of the most common is insomnia. Another very common one is obstructive sleep apnea. It affects approximately one in three men and approximately one in six women. Therefore, it is a very common condition in which snoring is one of the most common symptoms of obstructive sleep apnea.

It increases the risk of cardiovascular death by a staggering 420%. I'm just going to show you a slide that represents survival. So this graph starts on the left when the participants in the study were around 48 years old on average. And the percentage that survives is still there. And those in white are those who do not have sleep apnea and those in red have sleep apnea. And we will follow them for 18 years when they would be 66 years old. And you can see that at first there is not much difference between them. I mean, it's only about twice the risk of death.

But then you see that the risk of... that the survival rate is dramatically lower in those with sleep apnea. So when they turned 66, only 58% of them were still alive compared to 94% of those without sleep apnea.And unfortunately, those who survive in the sleep apnea group not treated here suffer cognitive decline about 10 years earlier and Alzheimer's disease about five years earlier than those without sleep apnea. So it's a really serious condition. And if you think you might be at risk for it, you should see your doctor and get evaluated. Now, let's see... here we go. Well, Benjamin Franklin said he'll get enough sleep in your grave.

And all I can say is that you'll get there much sooner if you don't get enough sleep. So, what are the things that rob us of sleep? Well, one of them is a relatively new invention: this electronic device, the iPad or some type of tablet. And it has two problems. Not only does it distract us and prevent us from wanting to go to bed because we are engaged, but it also bathes us in an enriched blue light that makes us more alert. And it also suppresses the release of the hormone melatonin that helps us fall asleep at night.

And it shifts our circadian rhythms to a later time, making it harder for us to wake up in the morning and we are more tired in the morning. Other than that, there is no problem reading from the iPad before going to sleep. Caffeine has a half-life of six to nine hours. And it keeps people awake because it promotes alertness: people use it to stay awake. But they don't necessarily realize that it lasts that long. That's why I'm always embarrassed when I see people order a double espresso after dinner. And they say, oh, it doesn't affect me.

YIt is true that there are inter-individual differences: approximately one in four people is particularly sensitive to the side effects of caffeine compared to the rest. But it disturbs everyone's sleep. And, of course, the bedroom television and all electronic devices should be outside the bedroom. You need to recharge. They need to recharge. So maybe it's best for you to recharge in another room. It's just something to think about. But of course, the goal is to be able to sleep soundly. And in order to sleep well and get enough sleep, we must make sleep a priority. And then there are things you can do.

When you wake up and that's when you set your alarm to wake you up. But one thing that can be very effective is setting a bedtime alarm: find out if you need seven to eight hours of sleep. Then if you set an alarm, let's say eight hours, because you don't sleep every moment you're in bed, so 8 and 1/4 hours before you know you need to wake up, that will help remind you. that it's time to go to bed. But there are several characteristics that are essential for sleep. One is duration. Most adults need between seven and nine hours of sleep per night.

It is essential that we obtain it at a constant time. Disrupting your sleep schedule can have just as adverse an effect as getting enough sleep. Therefore, consistency in sleep and wake time is really important. And finally the quality of sleep. If you have a sleep disorder like sleep apnea that prevents you from breathing and sleeping, for example, at the same time, then you won't get good quality sleep. And that will also interfere with its ability to function. If we get the sleep we need, then we will be more alert, we will perform better, our athletic performance and our cognitive performance will improve.

And also...just as a side note, we'll actually be more attractive to other people. There is a study published in the Journal of the American Medical Association in which they took portrait photographs of people when they had gotten enough sleep and then when those affected stayed awake all night. They took a shower. They were all cleaned for each of the two portraits. And people realized in four seconds... they were more attracted to the same person than... there were 700 images. They have done a very systematic study. But they found that people who had slept were more attractive, wanted to spend more time with them, etc., than people who were sleep deprived.

So there are many advantages to getting the sleep you need. And I thank you for your attention tonight. It is my great pleasure to introduce you to Professor Robert Stickgold, who will share with you his enormous work on sleep and memory, so thank you. Thanks, Chuck. And thanks to the program for inviting me. I'm delighted to be here. I'm going to talk about the dream. Yeah... get it or forget it. I'm going to talk about why we have to sleep and what we get out of it. Now, I've seen hands raised about how many of you aren't getting enough sleep.

So I think I'll repeat some of the things Chuck said because you know how that helps, right? So do we have to sleep? Well, this is what we know. We know that rats die without sleep. If you deprive a rat of sleep for two weeks, it will invariably die. So the rats need it. The same goes for humans. Now, Harvard Medical won't let us do that particular experiment. But there is a genetic condition known as fatal familial insomnia, which says it all. It is a prion disease. Harvard stood in my way. Can you see the bottom of this?

Some can and some can't. So there's an amino acid here... Oops, that's the wrong button! Back, back, back. There is an amino acid that is mutated in this protein. It is a prion disease like mad cow disease, except it causes middle-aged people, ages 40 to 50, to slowly lose the ability to sleep. And between one and four months after they stop sleeping, they all die. That's why humans also need sleep. And perhaps the most impressive data comes from studies of marine mammals, cetaceans, which cannot afford to sleep because if they fell asleep, they would sink and drown. And so evolution, instead of simply eliminating sleep, which would have been relatively easy as a genetic solution, taught these animals to sleep in one half of their brain at a time.

So they will sleep with only the right side of the brain and then they will sleep with only the left side of the brain. And that way they manage to continue swimming even if it's going around in circles and stay alive. So they need sleep and so do you. Now, today I am going to talk about several reasons why you need sleep. The main one will be about memory and learning, but I'm also going to go over some of the things that Chuck said in terms of immune function, in terms of hormonal regulation and removing toxins from the brain.

Chuck also mentioned mood regulation and learning and memory. So let's go through them one by one. And let's see if I can convince you. If you take a group of people and give them a hepatitis vaccine and then look at antibody production over time, it turns out that the body doesn't actually start making antibodies until after a couple of weeks. And during that time, the subjects who slept normally and those who were sleep deprived for a night after receiving the vaccine look quite similar. But over the next two weeks, you will see this effect. So, at 28 days, people who were sleep deprived for one night after receiving a vaccine will have only half the production of hepatitis antibodies, making it much more likely that they will not have enough vaccine to protect yourself.

Chuck mentioned the effects on insulin regulation. This is a study with subjects, college students, restricted to four hours of sleep per night, not total deprivation, but four hours of sleep per night for five days. And after that, the rate at which their bodies could remove glucose from the blood dropped by 40%. The acute insulin response was reduced by 30%. And they looked pre-diabetic. So just five days with half the normal record amount of sleep is enough to make it look like you have type 2 diabetes. And Chuck talked about clearing metabolites from the brain. Amyloid beta is one of two proteins that accumulates outside brain cells and is closely linked to the development of Alzheimer's disease.

And when you're asleep, you clear it from your brain twice as fast as when you're awake. And even a single night of sleep deprivation leads to a measurable increase in amyloid beta load in the brain. That's why I want to talk mainly about the evolution of sleep-dependent memory. I call it memory evolution because we used to talk about memory consolidation. This idea that you form a memory. And a few hours later, it's kind of cemented in your brain. And then it's there forever. But if you have a spouse of any gender, you are aware of this phenomenon that as time passes, your memories of events become separated.

Usually, it is your spouse's memory that becomes worse. But that kind of constant change of our memories over years and years is what I call memory evolution. And it's not just about whether you remember it or not, but the details of how you remember it. Here is an example. This is actually something Chuck touched on as well about the impact of sleep alone on the ability to remember, in this case, just words. Here is the protocol. Subjects are sleep deprived for a night (ah, too many buttons, not enough time) or sleep deprived for a night or sleep a normal night before entering the lab to be exposed to a couple hundred words on the screen.

They are negative and positive neutral words. They are simply asked to indicate whether it is a positive or negative or neutral word. And then, unbeknownst to them, when they return a couple of days later, they receive a surprise test. It was not unknown to them here. They didn't know it there. Then they give them the test, and it is a simple recognition test. They show them the 200 words they had seen before plus another 200 and ask them which ones they have seen before and which ones they haven't? And this is what we see. In the group that slept well the night before coding, recognition memory is quite high for both positive and negative words.

It reduces substantially for neutral words, but that's something we know a lot about our lives: we remember the emotional parts. But when we tested them two days later (sorry, when we tested the sleep-deprived ones) and, again, we tested them after two full nights of recovery sleep, so they are no longer tired. When we give them memory tests, their memory for positive words is reduced by about half, their memory for negative words is reduced by about half, but their memory for negative words is mostly maintained. Which means that if you were sleep deprived when you saw these words, you are twice as likely to remember the negative words as the positive or neutral ones.

So I'm in the psychiatry department. If someone comes to the psychiatrist and says, my wife says I have to go see a psychiatrist. She says I'm depressed because I only remember the bad things that happen. In truth, she may be depressed, but she may also simply be lacking sleep. That's enough to give you the feeling that only the negative things are remembered. That's bad on an individual level. It can be catastrophic at the national level. I have a suspicion that the entire cause of the first Gulf War, really, was now this effect. Because there were decision makers who were very sleep deprived trying to decide whether we should attack or not.

And remember that we have satellite photographs of these trucks that could be biological warfare weapons development trucks. We have to do something about it. And they forget that they were also told that they look like falafel trucks. And that's kind of funny, but that's where our mind goes when we have sleep restrictions, when we're sleep deprived. And decisions could be made on the basis of overrecall, an overreliance on negative memories. That's what happens when your sleep is limited and you lack sleep before you learn something. What my work really focuses on and what really surprised me when I found it and for most people is that the sleep you get after learning something is probably more important than the sleep you get before.

I'm the only professor whose lecture you'll attend who will take it as a compliment if you fall asleep while I'm talking. Because I know you're just trying to improve your memory of that event. Now, what effect does that have? Here is an example. I'm going to take you through three examples in total, but this is just a very simple test. What you're doing here is trying to learn to detect these diagonal bars in the lower left quadrant of your visual field when we show images like this on the screen very quickly. And what we do when we train it is we see how quickly we can display it up there, and it's still 80% accurate at detecting whether those bars are on top of each other like they're there or next to each other.

And then we'll bring you back 12 hours later and do the exact same test and again see how fast we can go before you can't do it. We found? Well, sorry, I'm saying let's bring you back. I assume you are all college students, yes, because that is how we did this study. ItWhat we found is that if we retest these subjects after 3, 6, 9, or 12 hours, there is no improvement in how quickly they can perform the task if they are awake during this time. But if we let them sleep between training and testing, they are 15% to 20% faster. It doesn't matter how long the interval is, it only

matters

whether they slept or not.

And, in fact, we can wait even longer to try them. These are groups of subjects that were evaluated. I showed you the 0 and 1 day data, but these are other groups tested after 3, 4, 2, 3, 4, or 7 days, and they continue to improve without any practice. So it's not practice that makes perfect. It is practice plus dream that makes perfection. And the terrifying finding is that if subjects are deprived of sleep during the first night after training, the subsequent sleep is worthless. So after two full nights of recovery sleep, your performance here is not significantly different from baseline. So you have to sleep and you have to do it tonight.

There's this concept of sleep bulimia, which is a compulsive purging concept that college students love. They binge sleep on the weekends and then purge themselves by sleeping four or five hours a night during the week. And they tell us that they are fine. They get it back on the weekend. Well, they may improve it in terms of becoming fully alert again, but it's actually too late to remember what they didn't remember because they didn't sleep that first night. Now. Sleep does much more complicated things than simply making our memories faster or stronger. It can do things like improve verbal memory in unexpected ways.

So we did a study and Jessica Payne was the leader. Sorry, many of my slides will include a list of my coworkers and students. I should make it clear that when I say we did something, I mean they did something. So with that admission, let me move on. The subjects in this study listened to eight lists of words on tape and told us to try to remember the words. We'll test you on them later. And then 20 minutes or 12 hours later, we'd try them. I'll give you an idea of ​​what that's like. I'm going to show you a list.

Now they heard it on an audio tape. I amI will show them the list and give them the same instructions that I gave them. Try to remember these words, they will test you. Well, in the actual study there were eight lists, not one. It was auditory, not visual. And in fact, we just gave them a blank sheet of paper on the new test and asked them to write down what they remembered. That here would be cumbersome. So I'll show you words and ask you to raise your hand if you remember seeing them. Now, for those of you who are not doctors, you may not know that there are extensor muscles in this part of the arm.

This is not raising your hand. This is not raising your hand. I want everyone around you to see how smart you are, okay? So if you remember seeing each of these words, raise your hand. Oh God. It's always embarrassing when we get... Okay, good, great, good... What can I say? Well, if you looked around, you'll know you weren't alone. In fact, all eight lists were generated in the same way. We gave words like sleep to a couple hundred psychology students in their introductory psychology course at college and told them to write down the first 10 words that come to mind when they think about sleep.

And then we took the 10 or 12 that wrote most frequently. And for each of the lists, we would show our study subjects those words, but not the word they were based on. And what we see is that classically between 60% and 80%, it seemed more like 90% of the subjects here, will respond incorrectly that they remember seeing the word. And that's because our brain is always extracting the essence. When you go home and tell your family and call your friends about my big talk, you will say that he showed us all the words related to sleep. And it doesn't matter what the words were, right?

It is only the essence that is important. And our brain is very good at identifying the righteous and retaining them. So the question Jess Payne asked was this: What happens to that memory over time? We had four groups of subjects; some were trained in the morning. Two groups trained in the morning and two in the afternoon. In each condition, one group was tested after just 20 minutes to give us an idea of ​​how well they formed these memories. And the other group was evaluated after 12 hours. And we can look at the difference to see how much they forget in 12 hours.

Now, those who were trained in the morning and tested that night were awake for all 12 hours. We told them not to take naps. While those who trained at night did the test and the next morning slept all night in the middle. And what do we see? Well, first of all, those in the wake group, throughout the day, forget about 40% or 45% of the words that the 20-minute group could remember. And even they have to sleep, they forget about 25% of those words. Those are the words they really saw. But when you look at the words that weren't shown, they're just words that the brain came up with, it still forgets about 20% of them during a waking day.

But during the night, the brain holds onto them tenaciously. He clings to the memory of what he believes is most important. So that when you wake up in the morning you have a memory that may be less accurate but more useful in understanding what happened. Now, one could imagine this happening for evolutionary reasons. In the previous one... no, bad language, sorry. Lack of sleep? So there's even... yes, I need more sleep, it's true. There are even more sophisticated and impressive things the brain does with our memories while we sleep. And here you have an example. In this study, subjects were shown 1, 2, or 3 of these cards on each of 200 trials.

And you were asked to predict whether it was going to be sunny or raining in this simulated world, which might not seem obvious to you. But fortunately, in these 200 trials we gave them feedback. So, for example, on the first test, they might see this card. And it turns out sunny. And if they are college students they say "whatever." And then on the second test, they might see these two cards together and it turns out to be rainy. And one of the fun things about the human brain is that it's always modeling, hypothesizing, and trying to understand.

So most of you at this point have probably said to yourselves: Well, that means sunny. And these two mean rainy. And I don't remember what the fourth was, but it probably means sunny too. So we build these models. And then, over 200 tests, we tested them. And then, actually, the third test comes and they say, Okay, I've got this one. And it turns out to be rainy. And now they are totally confused. In fact, they think I shouldn't have remembered correctly what happened here. But the trick of this study is that each of the cards has a certain probability of being associated with the sun or the rain.

So 80% of the time you see the triangles, it will turn out to be rainy. But only 20% of the time you see the squares would be rainy. And although no one can understand everything, they get a good model. It's a type of learning we call probabilistic learning and humans are terrible at it. But they understand the essence. So that after these 200 trials you always have feedback on the correct answer. We give them 100 tests without feedback and ask them if they are guessing which is the optimal option. And they get 70, 80 of them out of 100 correct. They are doing very well.

No one gets 100. No one fully understands the rules, but they're pretty good at it. Then we lay them off for 12 hours and do the exact same test, the same 100 words... sorry, the same 100 stimuli. And in subjects who were trained in the morning and tested that night without sleep, they got a couple of extra cards correct, but not significantly more than at baseline. It's impressive that they remember what they learned, but they certainly aren't getting better. After a night of sleep, they are 10% better. They do better on this task after a night's sleep than immediately after learning it.

In a very real sense, these guys, when they wake up in the morning, have a better understanding of how the world works than when they went to bed the night before. And that is what sleep provides them. So you need to sleep or rather you need to sleep. Sleep is necessary to maintain alertness and optimal cognitive functioning, optimize immune defenses, maintain hormonal regulation and weight, prevent amyloid beta buildup and Alzheimer's, enable sleep-dependent learning and memory consolidation and, as Chuck pointed out, simply to be happy. Or to put it another way, if you don't get enough sleep, you will end up stupid, fat, sick and unhappy.

The choice is yours, thank you, I will present it to you. It is now my pleasure to introduce you to Judy Owens, director of sleep medicine at Boston Children's Hospital and professor of neurology at Harvard Medical School. I was going to point that out again and simply say that the need for sleep in children cannot be overstated. I've always said that the phone call from hell is when a parent gets the call that says, Hi, I'm bringing Timmy over for his play dates. Oh, and today he didn't take a nap. Judy. Well, that's a big transition.

So my task in these last 20 minutes or so is to take some of the wonderful information that you've already learned from Dr. Stickgold and Dr. Czeisler and put it into the lens of the teenage brain. And we know that there is a lot of drama in adolescence and there is a lot of drama when we talk about the teenage dream. So the first thing I'd like to do is cover some common myths and misconceptions that I hear all the time from people like you who come to hear people like me talk about teen sleep. Number one: Teenagers would go to bed earlier if their parents simply made them do so.

So it's all a matter of bad parenting, of negligent parents who simply let their children get away with it. Some teenagers may need nine hours of sleep, but six is ​​enough for mine. And, in fact, so do I. If we remove cell phones, laptops, television, etc., children will fall asleep. If school starts later, they will simply stay up later and not be able to sleep anymore. Teens can make up for lost sleep by sleeping late on weekends. So that's the solution. And children need to learn to get up earlier, that's real life. They will have to do that when they are adults.

And what's the harm anyway? Well, let's look at some basics. This is what we call the two-process model of sleep regulation. And it's important to understand, especially when thinking about teenage sleep, because it goes some way to explaining why we feel relatively more awake or more tired at a certain time of day. So the first thing that regulates sleep is what we call the sleep drive. And Dr. Czeisler mentioned the buildup of adenosine in the brain, as well as other neurochemicals called somnogens, which essentially cause sleep. And that builds up pretty linearly throughout the day and then dissipates during a normal night's sleep.

The other process that regulates sleep is what we call the circadian rhythm or the circadian drive toward wakefulness. whose biomarker is melatonin... the hormone of darkness. And so circadian rhythms are essentially predictable 24-hour peaks and troughs of alertness and relative sleepiness throughout the 24 hours of the day. So, for example, between 3 and 5 pm we all feel a little sleepy. And we could have a Diet Coke or a Starbucks. That's a natural depression of circadian alertness. But we also have something called the no-go zone or second wind phenomenon, which is the increased circadian alertness that we all feel in that hour or so just before our bodies are ready to fall asleep, allowing us to stay awake in the face of a growing dream campaign.

And then, finally, there is the circadian nadir between 3:00 and 5:00 in the morning, which is the lowest point of alertness in the 24-hour day. Now I want you to consider this graph and imagine that it changes two hours later when we talk about what happens to sleep in adolescence. This was mentioned a little bit by the previous two speakers, but the importance of recognizing that what's important is not just how much you sleep but when you sleep. Because we now recognize that in addition to this master clock in the brain that determines when we sleep and when we wake up, there are also circadian clocks in all the cells of the body and in all the different systems, physiological systems of the body.

So misalignment between these internal circadian clocks and the external environment can lead to some of the profound health problems already discussed. That leads to this concept of what we call poor sleep, which recognizes that both short sleep relative to the amount of sleep needed and misalignment of the circadian system areequally important and both contribute to behavioral and cognitive impairments and poor health. results. So when we talk about what happens with sleep in adolescence, there's actually this perfect storm aspect. So what we have first is that all adolescents experience a normal change or delay in their time to fall asleep and their time to wake up in association with the onset of puberty.

That's why they develop more of what we call an evening chronotype or a night-owl tendency. This results in a two-hour shift or sometimes longer than the time they can fall asleep and wake up. And also sleep drive slows down during adolescence, so they may stay awake later. And on a practical level, because of that no-go zone (that increased alertness before the body is ready to fall asleep), it's very difficult for the average teenager to fall asleep much before 11 o'clock. regular way. Teenagers can't fall asleep sooner. Naturally, environmental influences also play a role in all of this.

All competing priorities for sleep, like extracurricular activities, homework, after-school employment. And this topic of electronics. Devices whose blue light, as Czeisler mentioned, actually suppresses the body's release of melatonin at night and makes it difficult to fall asleep. And we know that many teens consume caffeinated beverages, especially energy drinks. And that may also be exacerbating your difficulty falling asleep at night. And I'll talk a little bit at the end about the role of early start times. I just want to talk a little more about this topic of electronic devices. Because in a study that we recently did in adolescence, we looked at whether self-reported use of these light-emitting electronic devices, like smartphones or laptops, right before bed, how did that impact sleep duration in these students?

So what we found, as expected, is that students who were more likely to use these light-emitting devices slept less than students who didn't use them. However, and the reason for this study was to observe the impact of delaying school start time, is that students who use these devices before bed and those who did not sleep more after the change in school start time. Which implies that even the use of these light-emitting devices does not alter the potential benefits of changing school start times. That is why it is very important to eliminate this use of electronic devices at bedtime, but changing the start time of school can have an even more powerful effect.

There is also a phenomenon we call social jet lag. So what do teenagers do on the weekends? They sleep until noon or 1 in the afternoon. But this actually, as Dr. Stickgold clearly demonstrated, does not reverse the deteriorations they experience during the week. And it further exacerbates this tendency to sleep in, stay asleep later, and sleep later in the morning. So if you oversleep... if you sleep until 1 o'clock on Sunday afternoon, there's no way you're going to build up enough sleep drive to be able to fall asleep at a decent hour on Sunday night. And that results in this social jet lag situation.

So you may know that for every time zone crossed, it takes a day to recover. So these kids are essentially permanently jet lagged because they change shifts on the weekends. And then they try to come back during the week. And they change again on the weekends. And think about how you feel when you're jetlagged. It's not just that you're sleepy, it's that you're irritable. You may have all kinds of physical discomfort. It's not fun. And that's how these kids feel most of the time. So these changes, these biologically based changes are in direct conflict with earlier school start times.

Because you're essentially asking these kids to wake up at that circadian nadir, that lowest point of alertness in the 24-hour day. It's like asking us all to get up at 3 in the morning and go to calculus class. How would that feel? Not only that, but REM, rapid eye movement sleep, is concentrated in the last third of the night. So if you have to wake up too early, what will be robbed of you is your full complement of REM sleep. And as you may have heard, that has a potentially critical effect on learning, especially learning new tasks.

And furthermore, for optimal health, safety, and achievement (and that's what we all want for our children), the average middle school and high school student needs between 8 and 10 hours of sleep per night. We'll see how close we get to that. So you've already heard a lot of this. I'm going to talk very briefly about this. But when it comes to the adolescent brain, sleep restriction and lack of sleep have selective effects on this area of ​​the brain called the prefrontal cortex, which is intimately involved in the genesis of ADHD symptoms but affects really important higher-level functions. , such as decision making. and problem solving and monitoring and modifying their behavior.

And furthermore, these executive functions experience their most rapid development during adolescence. So, in this period when the brain is most vulnerable, these children are subjected to a situation that will negatively affect these particular brain processes. You may also have heard about the effect of sleep on emotional regulation. Basically, what we have is a sort of classic teenage scenario: a heightened emotional response to everything, but with less control over that emotional response. So maybe it's not all due to hormones. Perhaps much of the emotional reactivity in teenagers is related to not getting enough sleep. And finally, sleep also affects areas of the brain that are important for reward-related function.

And this area of ​​the brain, the striatum, is also undergoing some major developmental changes during adolescence. And studies suggest that lack of sleep is linked to changes in reward-related decision making, such that people take greater risks because they assume fewer negative consequences for their behavior. So how does all this play out in teenagers? Just a sad reminder that the first and third causes of death among teenagers in this country are accidents, including car accidents, and the third is suicide. So how does that relate to teenagers and sleep? Well, for example, in one study, a very large study of high school students, almost 40% overall were not getting enough sleep.

And it got worse as the grades went up. So, the percentage of students receiving less than or equal to six hours when they were in eighth grade was approximately 20%, but it increased to more than half, that is, 56% when they were in 12th grade. And minority students were more likely to get enough sleep. 40% of teens in the study who slept six hours or less reported symptoms of depression. And nearly three times as many students who slept less than six hours reported consuming alcohol in the past 30 days compared to those who slept more than nine hours. So this risk taking, this emotional regulation, this poor decision making is reflected in some very important health and safety outcomes.

Car accidents: Two-thirds of accidental injury deaths in adolescence are related to road accidents. And study after study has shown that teen drivers are more likely to report drowsy driving. And that is clearly a risk factor for being involved in car accidents. Surely you have heard about the relationship between sleep and certain neurohormones that control appetite. But there are many other reasons why sleep-deprived people may gain weight. They tend to eat more foods, with higher calorie content and higher fat content. If you wake up late, you may skip breakfast and consume most of your caloric intake in the evening, contributing to the development of obesity.

If you are too tired to exercise, that will exacerbate the problem. And we have these effects of lack of sleep on cardiovascular function added to the effects of obesity on cardiovascular function and insulin resistance and metabolism. And what's more, obese people are more likely to suffer from sleep apnea. And that adds another dimension to the risk of cardiovascular and metabolic health problems. So I wanted to leave you with a little optimism about all of this and offer a possible solution to the epidemic of insufficient and poor sleep in adolescence. And those are healthy school start times.

I had the privilege of being the lead author of the 2014 American Academy of Pediatrics policy statement advocating for an 8:30 or later school start time as best for our nation's youth. And this concept has been endorsed by many organizations, including the American Medical Association, the American Psychological Association, the American Thoracic Association, the NEA, and the national PTA. So there are a lot of people who are on board with us. Because some of the results that have been shown in studies that have looked at the impact of delaying school start times for middle and high school students have found that bedtime remains roughly the same or may even change earlier.

But because they sleep late in the morning, these students get significantly more sleep, particularly that critical morning sleep, REM sleep, that I mentioned. The later the start time, the greater the amounts of sleep, but even relatively small amounts may result. In significant improvements. And students report being less sleepy. And it really seems like 8:30 or later is the sweet spot both in terms of allowing students to get the sleep they need and also getting it at the right time that's in tune with their circadian rhythms. In terms of school performance, tardiness rates decrease, absenteeism decreases, dropout rates decrease, and graduation rates increase in schools that have delayed their start times. and grades overall improve, particularly in morning classes, as you can imagine, but in core subjects, such as English, math, and science.

And there is some evidence to suggest that disadvantaged students, students at the lower end of academic success, and minority students, may benefit even more from the change in school start times. Standardized test scores improve and delaying the start of school is also associated with improvements in mood. Every study shows that self-reported depression symptoms decrease. Fewer visits to the health center and, perhaps most importantly, there is now evidence to suggest that changing school start times can decrease the risk of students being involved in car accidents by up to 65% to 70% in some studies. Now, as a public health specialist, it's hard for me to imagine another strategy that could affect mortality, that could affect car accident mortality rates, as much as this.

And of course, we can't absolutely extract a cause and effect from these studies, but evidence is accumulating that there is this association between later school start times and fewer accidents in general, but particularly car accidents. And finally, if you just want to talk dollars and cents, there was a big study published by the RAND Corporation that looked at...they used an economic model of what would happen state by state if the entire state changed their school start times. at 8:30 or later. They did it in 47 states. And the way they calculated this was to look at, well, it's going to cost about $150 per student per year, and that's largely related to transportation costs like purchasing more buses, etc., plus $110,000 for infrastructure, maybe lighting playing fields for Athletic teams can play later in the afternoon.

But then they balanced that by looking at projected lifetime earnings based on better graduation rates and better standardized test scores plus what would be earned if fewer students were involved in car accidents. And if we look at this over 15 years, as examined in the study, the average annual gain based on those parameters for the US economy would be about $9.3 billion per year. In some states, like Massachusetts, being one would allow you to break even in terms of the cost of changing start times in just two years and then start making money. So, this study really suggests that delaying the start of classes is a cost-effective strategy at the population level, which could have an effectsignificant to the health of our nation's youth as well as the American economy.

Thank you so much. It's wonderful to see all the people coming home to bed. That was fantastic, Judy. Oh thanks. There is so much new data. I know, it's really exciting. Fantastic, yes. It's just that the evidence is so irrefutable. Alright. Well, thank you all for coming. For those of you who have to leave and for those who stay, we will be happy to answer your questions. So we have some questions. Actually, many more than we could answer. I've tried to group them together. . And why don't we start with Bob? He has some questions about naps.

There are a lot of questions about napping. I'll just give you an idea of ​​them. Efficiency of naps to cover the body's needs. Is it better to stay? Oh, that's not one. Oh, these are the new ones you gave me, Chuck. How often should we take a nap? Can we catch up on lost sleep? Is it possible to make up for lost sleep by taking naps during the day? So taking a nap is wonderful, right? Personally I think you should take a nap whenever you can. They are effective in meeting our need for eight or nine, seven to nine hours of sleep per night.

Naps are hour for hour as effective as sleeping at night. But when it comes to memory processing, it turns out that a 90-minute nap offers just as many benefits as an eight-hour night. This is something that has actually left us stunned. And we've seen time and time again that, in fact, a 90-minute afternoon nap produces more memory benefits than a six-hour night. That's why naps have something special. Someone asked how often should we take a nap? There is no set frequency with which you should take a nap. You probably shouldn't count on naps to make up for lost nights, although you can use them that way.

Preventative napping is something I wouldn't recommend. I wouldn't recommend trying to take a nap so you don't get as much sleep as you do at night. But when and when you need to nap, it seems to be very effective. That said, we don't have data for things like immune function, endocrine function, hormonal function, and removal of toxins from the brain. We don't have nap studies for those. And so the question of how well they work compared to a night's sleep, we don't know that information. One thing I would simply like to clarify. Naps are not a substitute for nighttime sleep.

A police officer once came up to me and I talked to him about the benefits of taking a nap. And he said, well, doctor, I just want you to know that's exactly what I do. I sleep in the afternoon. But then he explained to me his schedule. He didn't sleep at all at night. So I slept two hours a day. So that's certainly not a good plan. That is a very bad plan. And again, nap time is important too. Because if you nap later in the afternoon, you are reducing the pressure of sleep and it becomes much more difficult to fall asleep at night.

So the optimal time to take a nap is probably in the early afternoon. That is, at the classic nap time. And Professor Owens has some questions about the dream. Yes. So I have several questions about how much sleep children of different ages need. And I think the American Academy of Sleep Medicine has optimal amounts of sleep published on their website for children of different ages, as does the National Sleep Foundation. But what I would say about it... and it happened today that I had a patient, a family that came in with a 3-year-old child. And the parents were worried that the child wasn't getting enough sleep because they weren't meeting the numbers.

And first of all, there is always a variety. So this particular question was about 10 years. How much sleep does a 10 year old need? Probably between 10 and 12 hours. But it's always a range. And there were three questions that I asked this family. Does your child wake up alone at the time he needs to wake up in the morning? If the answer is yes, it means he probably got enough sleep. When given the opportunity, do they sleep longer? So on the weekends, they sleep 10 hours during the week, but then when they can, they sleep 12 hours? That probably means that weekday sleep isn't enough.

And finally, how is your child functioning? They are happy? Do they wake up in a good mood? Are they paying attention at school? Is there any concern on the part of the teacher? And if the answer is no, then don't worry so much about the numbers. If that makes sense. One of the questions we ask ourselves is: does sleeping too much have negative effects on our health? Because we talk a lot about the adverse health effects of sleeping too little. Epidemiological data now indicate that people who sleep more than 10 hours a night have a higher risk of death.

From there it could be concluded that sleeping too much is bad. But in general that is not the case: first of all, the number of people in those groups when they do the epidemiological studies who lose 11 or 12 hours a night are very small compared to the general population, because that is very rare in our society. Secondly, sleeping too much could be a symptom of an illness. I mean, when I was in college, I had toxoplasmosis. Anyway, I slept like 20 hours a day. Not because... because he was sick. And many times, at that time the cause of the disease is not even known.

So the general interpretation of the data that people who sleep a lot are at higher risk for disease, they may not realize they have a disease. But they may have some early manifestation of a disease that later comes to light. And why is that the view? Well, if you take healthy people and put them in the lab and make them spend 14 hours a night in bed in the dark, instructing them to sleep for a month, you might think this is the ideal job. All you have to do is go to the lab and sleep every night for 14 hours.

And it turns out that, first of all, if you only take people who sleep between seven and eight hours, the first night they could sleep between 11 and 12 hours. And then the next night, 10 or 11 hours, and so on. But it's not like eating. We really can't fall asleep. So after the first week, the second week, and at the end of the fourth week, they sleep on average 8.2 to 8.4 hours a night, even though they are in bed for 14 hours a night. So we really can't... it's not like overeating where we can gain weight. We cannot continually fall asleep and somehow accumulate some kind of adverse effect.

In fact, the sleep system, once it is sated and once we have paid the sleep debt that we often carry, and Bill Dement, who was my advisor in college and who was instrumental in understanding and developing the concepts behind During REM, I used to say that the sleep debt, the national sleep debt, is greater than the national debt because, as a society, we are chronically sleep-deprived. And the average person in that study didn't reach 8.2 hours a night until he paid off about 30 hours of sleep debt he had been carrying by sleeping a couple of extra hours.

Now many people sometimes feel more groggy if they occasionally sleep late. And that's probably a reflex, because we all experience a phenomenon called sleep inertia where the deeper we sleep, the more groggy we are when we wake up. And probably, if you pay off a lot of your sleep debt at once, you might feel a little groggy when you wake up. But that's only because he's beginning the road to recovery. Not because sleeping too much is harmful. So Bob, do you have another question? Are geniuses (writers, artists, scientists) disproportionately sleep deprived? Ask. If we solved the sleep crisis, would the pace of human advancement slow appreciably?

There is a concept that people who light the candle at both ends are more productive than other people. In fact, Bill Gates once said that when his teams have a deadline to launch a product, they can schedule 72 hours straight without sleeping. And my answer is yes, but the product is Windows. So no... there is a belief that the number of hours you work is a measure of your productivity. And it is not. I mean, the great advances of writers, artists, scientists, those revolutionary discoveries, those brilliant ideas, do not arise from long hours. They probably come from well-rested brains.

In fact, I'm convinced that the reason Newton came up with his theory of gravity was not because the apple hit him on the head but because he had been sleeping under that tree. There you go. And, indeed, there is much evidence of important creative discoveries; the scientists themselves reported that they occurred during sleep. Because it is that insight gained during particularly REM sleep that helps us, as Bob so eloquently describes, put together the information of the individual things we have learned, integrated with everything we have previously known. And it's worth noting that most REM sleep occurs at the end of the night rather than the beginning.

And one of the related questions is that many successful CEOs say they sleep too little. And that's... Thomas Edison, he had a little interest in this because he didn't want his employees to sleep. And that's why he was always extolling the virtues of staying awake. But in fact, many CEOs, current CEOs like Jeff Bezos, talk at length about how important it is for them to get the sleep they need. And that they spend at least eight or nine hours in bed every night. And Apple's Tim Cook is also famous for talking about the importance of getting enough sleep.

So I think a lot of times... you know, when we hear people claim that they don't sleep at all or whatever, when they actually go into the lab, that's usually not confirmed. In fact, we had one individual who claimed that he needed so little sleep that he had a second job, and that he was...and he felt sorry for people who needed eight hours of sleep a night. So we took it to the lab. I didn't know what time it is. No clocks, no radios, no source of time of day information. And immediately, he expanded his dream.

And he said, you know, I've never felt better in my life. This is great. What's going on here? Etc. And I said, well, you're sleeping almost eight hours a night. And he said, well, maybe he was exhausted. I have a couple of questions about special populations of children. First, children with ADHD and children with autism. Special populations. Special populations, yes. I'm sorry. So I would say a couple of things about that. Many, many children with ADHD, particularly autism spectrum disorders, have significant sleep problems. I think there is no doubt about that. In particular, children with ADHD tend to have trouble falling asleep.

Children with autism often wake up during the night. They may have a relatively short sleep duration. And I think it's still unknown whether they really need less sleep than typically developing children. But I think... a couple of points about that. One is that if children within those populations have sleep problems, many of the same behavioral interventions that we use in typically developing children also work very well in those populations. There is some evidence, there are a number of studies that have suggested that children with ADHD and autism may have changes in the release of melatonin at night that may affect their ability to fall asleep at a regular and appropriate rate. time.

And there is also some data to suggest that using artificial melatonin may help these children. But I would add a big note of caution in saying that any time you use any type of sedative medication (and this applies to both adults and children) you have to combine it with behavioral interventions. Because otherwise, when any medication, whether over-the-counter or prescription, is discontinued, the problem will still be there unless behavioral strategies have been instituted that actually result in long-term improvements. I ran an ADHD clinic for 25 years. And I don't... generally speaking, and studies confirm this, is that daytime ADHD medications, because they wear off relatively quickly, most of these medications leave your system by dinner time. . - for the most part, do not directly affect sleep onset in children with ADHD.

But I think what happens more often is that they are not medicated. In that time between dinnertime and bedtime, ADHD symptoms return. Impulse control, hyperactivity, etc. And that contributes to their problems being resolved rather than being a direct effect of the medication per se. But in terms of addressing sleep problems, particularly in children with autism, I very often refer parents to the Autism Treatment Network website, which has wonderful resources, particularly on sleep, and has one of the best balanced summaries of the pros and cons. about the use of melatonin in children that I have seen. This is a great resource for parents struggling with these types of issues.

Do you want the name of the website? It is the Network ofAutism Treatment. Two more questions. Two more questions. And we have so many. I know. I'm going to break your rule right away by answering two YouTube questions shortly. To what extent do daytime activity levels affect the amount of sleep needed at night? In terms of physical activity, I think the answer is almost zero. Your heavy work doesn't particularly need more sleep time. Is this correct? Chuck, do you agree? I agree. Than your college professor whose biggest physical activity is clicking the mouse. At the same time, emotional labor, emotional distress, could lead to the need for more sleep and could produce more sleep.

And a lot of exercise could increase the depth... That's the second one. How does the timing of exercise affect sleep? Do you recommend exercising in the morning or at night? So anything that raises your core body temperature, the temperature of your body inside, will make it easier for you to sleep. Therefore, exercise or hot tubs can make it easier to fall asleep and deepen your sleep. But you don't want it to be too close to the onset of sleep. Therefore, up to an hour before bedtime is probably optimal. Both from YouTube. And for the second group of questions.

You can't silence us. I'm going to group two. It's a bit of a stretch to call them a group. But one has to do with the resident doctors' work schedules, which are atrocious. And we just took a step back where, despite all the evidence that's been produced showing that resident physicians who work these long-duration shifts have a higher risk of motor vehicle accidents, a higher risk of making medical errors serious in patient care. they are treating, increased risk of needle stick injuries. However, the restrictions that existed for some years have been lifted. And now again they can be scheduled to work such long shifts, which I think is a big mistake.

And then they wonder why so many doctors are burned out. Etc. And the correlated question is why do they keep waking up patients in the hospital if sleep is so important for health? And I don't know the answer to that question. It can be a little strange in the hospital. And the last series here is about interindividual differences in the need for sleep. Yes, there are interindividual differences in the need for sleep. And yes, the amount of sleep we get as we age (there are a lot of questions about sleep and aging) the amount of sleep we can get decreases.

And the depth of sleep also decreases. It doesn't really answer the question of whether we need less sleep. We may not be able to sleep as much as we get older. And the number of awakenings during the night increases. But I just want to say one thing about the awake state: there are interindividual differences in the time people spend in bed. But the number of people who need to sleep five hours or less per night, expressed as a percentage and rounded to a whole number, is 0%. So if you sleep so little, you are undoubtedly getting an insufficient amount of sleep.

And that's a quote from one of my colleagues, Tom Roth, who put it beautifully. But many people think their sleep is perfect if they never wake up during the night. And in fact, it is normal for us to wake up during the night. We might get up, go to the bathroom, this, that. And if we are achieving it, the ones who, going back to the resident doctors, the ones who never wake up are the ones who are severely sleep deprived. So when we study resident doctors who sleep and they only sleep four or five hours a night, they sleep soundly.

By the time they go to sleep, they go to bed, they are asleep. The moment they wake up, they get up. So people who say I'm a sleep champion. I can fall asleep anywhere and anytime. On a bus, on a plane, anywhere. In reality, they probably suffer from chronic lack of sleep. And as usual, a couple of hundred years ago, before the advent of artificial light, people probably had segmented sleep. There is evidence from historians that they slept soundly at the beginning of the night. I woke up, I attended to the animals. Some people think that most children were conceived in the middle of night wakings.

And then people returned to enjoy the sweet sleep, the REM sleep of the morning hours. And finally get out of bed. So we have medicalized the concept that if you wake up once or twice during the night you need medication. But in reality, it can be quite normal to wake up during the night. And that can be a sign that you're actually getting enough sleep.