The New Science of Sleep and Dreams | Professor Matthew Walker

so thank you all for coming and Matthew over to you thank you well it's always dangerous to receive a round of applause before you've done anything because that assumes that you're going to be good enough it it's a privilege and delight to be speaking with you it's safe to say that when most speakers look to their audience and see people who are sort of falling asleep or nodding off it can be profoundly disheartening however based on the topic of this presentation I'm going to actively encourage that kind of behavior from you in fact knowing what I know particularly about the relationship between sleep and memory it's the greatest form of flattery for me to see people like you not being able to resist the urge to strengthen and consolidate what I'm telling you by falling asleep so feel free just a sort of ebb and flow in and out of consciousness throughout the entire talk I'll take absolutely no offense and I would like to begin with testicles men who sleep five hours a night have significantly smaller testicles than those who sleep seven hours or more in addition men who routinely sleep just four to five hours a night will have a level of testosterone which is that of someone ten years their senior so a lack of sleep will age a man by a decade in terms of that critical aspect of wellness and we see equivalent impairments in female reproductive health caused by a lack of sleep this is the best news that I have for you this evening from this point forward it may only get worse not only will I tell you about the wonderfully good things that happen when you get sleep but the alarmingly bad things that happen when you don't get enough both for your brain and for your body let me start with the brain and the functions of learning and memory because what we've discovered over the past 10 or 15 years is that you need sleep after learning to essentially hit the Save button on those new memories so that you don't forget so sleep will actually future proof that information within your brain but recently we discovered that you also need sleep not just after learning but also before learning and now to actually prepare your brain I'm almost like a dry sponge ready to initially soak up new information and without sleep the memory circuits of the brain essentially become waterlogged as it were and you can't absorb new information so let me show you the data so here in this study we decided to test the hypothesis that pulling the all-nighter was a good idea so we took a group of healthy adults and we assigned them to one of two experimental groups a sleep group and a sleep deprivation group now the sleep group they're going to get a full eight hours of slumber but the deprivation group we're going to keep them awake in the laboratory under full supervision and there's no naps by the way there's no caffeine it's miserable for everyone involved and then the next day we're going to place those participants inside an MRI scanner I'm going to have them try and learn a whole list of new facts as we're taking snapshots of brain activity and then we're going to test them to see how effective that learning has been and that's what you're looking at here on the vertical axis so the higher up you are the more that you learned and when you put those two groups head-to-head what you find is a quite significant 40 percent deficit in the ability of your brain to make new memories without sleep I think this should be frightening considering what we know is happening to sleep in our education populations right now in fact to put that in context would be the difference in your child acing an exam versus failing it miserably 40% and we've gone on to discover what actually goes wrong within your brain to produce these types of learning disabilities and there's a structure that sits on the left and the right side of your brain called the hippocampus and you can see it here in these sort of orange yellow colors think of the hippocampus like the informational inbox of your brain it's very good at receiving new memory files and then holding on to them and when we looked at the structure in those people who'd had a full night of sleep here in green we saw lots of healthy learning related activity yet in those people who were sleep deprived we actually couldn't find any significant signal whatsoever so it's almost as though sleep deprivation had shut down your memory inbox and any new incoming files they were just being bounced you couldn't effectively commit new experiences to memory I'm parenthetically if you'd like to know what life is like without a functioning hippocampus just watch the movie memento I suspect some of you have seen this as a great movie this gentleman suffers brain damage and from that point forward he can no longer make any new memories he's what we call densely amnesiac the part of his brain that was damaged was the hippocampus and it is the very same structure that sleep deprivation will attack and block your brain's capacity for new learning so that's the bad that can happen if I were to take sleep away from you but let me just come back to that control group here in green remember those folks that got a full eight hours of sleep well we can ask a very different question what is it about the physiological quality of your sleep when you do get it that restores and enhances your memory and learning ability each and every day and by placing electrodes all over the head what we've discovered is that there are big powerful brain waves that happen during the very deep first stages of sleep that have riding on top of them these spectacular bursts of electrical activity that we call sleep spindles and it's the combined quality of these deep sleep brainwaves that acts like a file transfer mechanism at night shifting memories from a short-term vulnerable reservoir over to a more permanent long-term storage site within the brain and therefore protecting those memories and making them safe and it's important by the way that we understand what it is during sleep that transacts these memory benefits because there are real medical and societal implications and let me just tell you about one area that we've moved this work out into clinically which is the context of aging and dementia because I think it's no secret of course that as we get older our learning and memory abilities begin to fade and decline but what we've recently discovered too is that a physiological signature of aging is that your sleep gets worse and not just any type of sleep especially that deep quality of sleep that I was just discussing and only last year we finally published evidence that these two things they're not simply co-occurring they are significantly interrelated and it suggests that the disruption of deep sleep is an underappreciated factor that is contributing to what we call cognitive decline or memory decline in aging and most recently we've discovered in Alzheimer's disease as well now I know this is somewhat depressing news it's in the mail it's coming at you but there's a possible silver lining here because unlike many of the other factors that we know are associated with brain aging for example changes in the physical structure of the brain or even changes in the blood flow dynamics of the brain those are fiendishly difficult to treat and we in medicine we have no good approaches right now but that sleep is a missing piece in the explanatory puzzle of Aging in Alzheimer's is exciting because we may be able to do something about it and one way that we are approaching this at my sleep center is not by using sleeping pills by the way they unfortunately do not produce naturalistic sleep and they have been associated with a significantly higher risk of death as well as cancer and I'm happy to speak about that during the Q&A but instead we're actually developing a method and based on this it's called direct current brain stimulation you insert a small amount of voltage into the brain so small that you typically don't feel it but it has a measurable impact now if you apply this stimulation during sleep in young healthy adults as if you're sort of singing in time with those deep sleep brainwaves not only can you amplify the size of those deep sleep brainwaves but in doing so we can almost double the amount of memory benefit that you get from sleep the question now is whether we can translate the same affordable potentially portable piece of technology into older adults and those with dementia can we restore back some healthy quality of deep sleep and in doing so can we salvage aspects of their learning and memory function that is my real hope now that's one of my moonshot goals as it were with sleep so i by the way i should note because i always get asked the question people say where can i buy one of those devices I want one yesterday and I want five more tomorrow and they are not yet currently approved for use in sleep you can buy them on the internet I strongly advise against that you've gone to youtube if you google around people have misaligned the voltage they've got skin burns they've lost their eyesight for several days don't try this at home were desperately trying to bring this to fruition um so that's sleep for learning memory aging Alzheimer's disease that's sleep as an example for your brain but sleep of course is just as essential for your body we've already spoken a little bit about sleep loss and your reproductive system or I could tell you about sleep loss and your cardiovascular system and that all it takes is one hour because there is a global experiment performed on 1.6 billion people across 70 countries twice a year and it's called daylight savings time now in the spring when we lose one hour of sleep we see a subsequent 24% increase in heart attacks the following day in the autumn when we gain in an hour of sleep we see a 21 percent reduction in heart attacks isn't that incredible and you see exactly the same relationship for car crashes road traffic accidents even suicide rates but as a deeper dive I actually want to focus on this sleep loss and your immune system and here are introduced these delightful blue elements in the image they are called natural killer cells and you can think of natural killer cells almost like The Secret Service agents of your immune system and they are very good at identifying dangerous unwanted elements and eliminating them in fact what they're doing here is embedding themselves into a malignant a cancerous tumor mass and destroying it so what you wish for is a variety of these immune assassins at all times and tragically that's what you don't have if you're not sleeping enough so here in this study you're not going to have your sleep deprived for an entire night we're simply going to restrict your sleep to four hours for one single night and then we're going to look to see what is the percent reduction in immune cell activity that you suffer and it's not small it's not ten percent or thirty percent there was a 70 percent drop in natural killer cell activity that's an alarming state of immune deficiency and it happens quickly essentially after one short night of sleep and you can perhaps now understand why we're finding significant links between short sleep duration and your risk for the development of numerous forms of cancer currently that list includes cancer of the bowel cancer of the prostate and cancer of the breast in fact the link between a lack of sleep and cancer is now so strong that recently the World Health Organization decided to classify any form of nighttime shift work as a probable carcinogen jobs that may induce cancer because of a disruption of your sleep wake rhythms so you may have heard of that old maxim that you can sleep when you're dead well I'm being quite serious now it is mortally unwise advice if you adopt that mindset we know from the data that you will be both dead sooner and the quality of that now shorter life will be significantly worse it's what epidemiological studies teachers across millions of individuals the shorter your sleep the shorter your life short sleep predicts all cause mortality and if increasing your risk for the development of cancer and/or even Alzheimer's disease were not sufficiently I'm disquieting we have since discovered that a lack of sleep will even erode the very fabric of biological life itself your DNA genetic code so here in this study they took a group of perfectly healthy adults and limited them to six hours of sleep a night for one week and then they measured the change in their gene activity profile relative to those same individuals when they were getting eight hours of sleep a night and there are two critical findings first a sizable and significant 711 genes were distorted in their activity caused by a lack of sleep this is relevant by the way we know that one out of every two adults in developed nations is trying to survive on six hours of sleep during the week the second result was that about half of those genes were actually increased in their activity the other half were decreased now those genes that were actually switched off by a lack of sleep were genes associated with your immune system so once again you can see that sort of immune deficiency playing out those genes that were actually increased or what we call upregulated were genes that were associated with a promotion of tumors genes that were associated with long term chronic inflammation within the body and genes that were associated with stress and as a consequence cardiovascular disease there is simply no aspect of your wellness that can retreat at the sign of sleep deprivation and get away unscathed it's almost like a broken water pipe in your home sleep loss will leak down into every nook and cranny of your physiology even tampering with the very DNA nucleic alphabet that spells out your daily health narrative and at this point you may be thinking my goodness so how do I get better sleep what are your tips for good sleep well I think we'll go into detail but I have at least two tips and beyond avoiding the damaging and harmful impact of alcohol and caffeine on sleep and by the way if you're struggling with sleep at night you should avoid naps during the day the two additional pieces of advice are this the first is regularity so go to bed at the same time wake up at the same time no matter whether it's the weekday or the weekend regularity is king and it will anchor your sleep and improve the quantity and the quality of that sleep the second is keep it cool your body needs to drop its core temperature by about one degree Celsius to initiate sleep and then to stay asleep and it's the reason you will always find it easier to fall asleep in a room that's too cold than too hot because too cold is taking you in the right temperature direction for good sleep so finally in sort of taking a step back what is the mission critical statement that I would love to leave you with at this stage well I think it would be this sleep unfortunately is not an optional lifestyle luxury suite is a non-negotiable biological necessity it is your life support system and it is mother nature's best effort yet at immortality and the decimation of sleep throughout industrialized nations is having a catastrophic impact on our health or wellness even the safety and the education of our children it is a silent sleep loss epidemic and it is fast becoming one of the greatest public health challenges that we face in the 21st century I believe it is now time for us to reclaim our right to a full night of sleep and to do so without embarrassment or that unfortunate stigma of laziness and in doing so we can be reunited with the most powerful elixir of life the Swiss Army knife of health as it were and with that soap box rant over I will say at this point good night good luck and above all I do hope you sleep well thank you very much thank you thanks a lot it's not time to sleep I think just yet thank you very much I think for that it's obviously a lot of that is quite alarming and before we go into what we can do and you know hope that slightly more optimistic things for people to go away with and this answer I think depends perhaps on the age of the person asking but it's if you're listening to that and you haven't prioritized sleep up until now is it too late so firstly let me say that you know when I speak about sleepers sort of not a luxury item and it's non-negotiable I also do understand of course working in the field that in 10 to 15% of the population struggles with sleep and so they give themselves the opportunity but biologically physiologically psychologically and there's a number of reasons they can't obtain or generate that sleep so I just know that I have complete sympathy for that I'm not trying to dismiss that and is it too late to start it is never too late to start with one caveat firstly sleep is not like the bank you can't accumulate a debt and then hope to pay it off at a later point in time let's say at the weekend so sleep in that sense is an all or nothing event and by the way we can ask the question why why isn't there a system like why isn't there a credit system for sleep because there is biological precedent for this and it's called the fat cell because there were times during our evolutionary past when we faced famine and feast and your body came up with a solution for that called the fat cell the adipose cell so that when you had a feast you could store that caloric energy as fat and when you went into famine you could spend it like credit when you went into debt where is the fat self asleep and the answer is human beings are the only species that deliberately deprived themselves of sleep for no apparent reason in other words mother nature throughout the course of evolution has never had to face this challenge of sleep deprivation so she's never had to build a safety net in place that's why we implode so demonstrably when sleep gets short but to finally answer your question it isn't too late and I don't say that just to be kind of rarrrr and encouraging we have the evidence so the study that we we were a part of where we took a group of people in their 50s who had untreated sleep apnea which is essentially heavy snoring and if there's anyone out there who snores and snores heavily and is untreated go to your GP it's a deathly disease but we assigned them to a treatment and that treatment is the sort of this face mask that keeps your airway open it's not a great treatment but through a trick of nature about half of the participants complied to the treatment and kept using it and their sleep got better the other half didn't use it anymore and we were able to then track those patients and what we found is that those people who had hid the treatment and whose sleep got better they staved off the onslaught of Alzheimer's disease by up to ten years earlier than those people who didn't stick with the treatment so that is a causal manipulation that even in your 50s if you improve your sleep you improve your longevity your lifespan and your you mentioned people who can't sleep people often can't sleep because of anxiety what is your advice for people who physically just cannot get themselves to sleep so anxiety yeah is probably the principle underlying reason for insomnia there are other causes of but anxiety seems to be the principal cause and what happens is that the there's a part of your nervous system called the fight-or-flight branch of the nervous system that when you are stressed or anxious get sort of ramped up now when you go to sleep that part of the nervous system actually has to get shut off and you can't fall asleep if it's turned on and I have this when we speak to patients in the sleep center who have anxiety and have insomnia and they are what we call wired and tired that they are desperately tired they are desperately sleepy but they can't see because they're too wired with anxiety what do you do about that well firstly you can't just put you know a plaster on it and sort of numb it with medication because you have to address the root cause firstly finding out what's causing you the anxiety is one place but when it comes to sleep there are several things you can do the first is meditation now I was I'm quite a hard neuroscientist and when I was researching for the book the meditation literature I thought it was going to be a bit woowoo and that was sort of you know four and a half years ago and I started practicing meditation myself and I haven't stopped for four and a half years and when I struggle with sleep at night especially when it comes to jetlag for example I use meditation to help quieten down that fight-or-flight branch of the nervous system and then it helps me slip into sleep the other thing is doing a worry Journal about an hour before bed because one of the things that happens with people with insomnia is that they either can't fall asleep because they're thinking about what didn't they do what should they do what needs to be done tomorrow and they catastrophize they ruminate or you wake up in the middle of the night you try get to get back to sleeping all of those things reimagine all comes in so an hour before bed just sit down write out all of the things that are on your mind and it's catharsis it's sort of like vomiting out your anxiety and stress on the page and it turns out the data is very robust when you do that you fall asleep in half of the time that you would otherwise I think the problem is that a lot of people worry about the fact that they can't sleep and that's a vicious cycle it is and you know I think that's in some ways that was probably some of the pushback that I got from the book is you know I wanted to be truthful I wanted to convey the importance of sleep to society because I felt as though you know I at least hadn't done a good job of that and I wanted to do that and I had to be truthful I had to write the story that the science it is describing but I think some people found it so alarming especially those people who are struggling with sleep that it only made their cause worse as it were so I think the answer there is try not to worry too much understand that tonight may not be your night and secondly if you're lying in bed awake don't stay in bed because your brain is an incredibly associative device and very quickly it learns that this thing called your bed is the place of being awake and not asleep and so you need to break that Association and the way that you do it is if you haven't fallen asleep after 15 or 20 minutes or you haven't fallen back asleep get up go to a different room in dim light just read a book do something relaxing meditate only return to bed when you are sleepy and there is no time limit only when you are sleepy and that way you will relearn the Association that your bed is the place of sound sleep not the place of wakefulness so I think the analogy there would be you would never sit at the dinner table waiting to get hungry so why would you lie in bed waiting to get sleepy I want to come back to some of the optimal conditions and the things we should do but you mentioned sleeping pills in your talk and I think you've said that they they absolutely don't produce natural sleep we should keep away from them are there any kinds of natural there any natural pill anything that you would say you can take before we can get your fantastic device so we don't know of any pharmacological compounds that have been produced yet that produce a naturalistic sleep or be really exceed anything that you see with placebo and the fact that those sleeping medications come with a collection of deleterious effects led in America for example in 2016 the American College of Physicians made a landmark recommendation based on the weight of that danger relating to sleep medications and how little they truly benefit above and beyond placebo they said sleeping pills must no longer be the first line recommendation for insomnia the alternative and we have a good one is called cognitive behavioral therapy for insomnia or CBT I so if anyone is interested in this if you just go to the NHS website and type in CBT I or type in insomnia and look for cognitive behavioral therapy for insomnia you will find it they do a great job of introducing it you can do a little sleep test to see how bad your sleep is so we have a safe psychological treatment for insomnia that is just as effective as sleeping pills in the short-term but what's great is that once you stop working with the therapist you continue on with the benefit in terms of sleep improve whereas with sleeping pills if you stop them not only do you go back to the bad sleep that you were having before you actually have what's called rebound insomnia which is that your sleep is even worse than it was when you started taking them the other thing you say keep off is alcohol and caffeine altogether or when when are you able to drink coffee and when alcohol and still be able to sleep yes so this I mean I'm generally an unpopular person but these these make me deeply unpopular so let me sort of go through them alcohol is probably the most misunderstood sleep aid out there it's not a sleep aid at all people often turn to alcohol to help them with sleep but it's a problem for three reasons firstly alcohol is a class of drugs that we call the sedatives and sedation is not sleep but when you drink in the evenings you mistake the former for the latter but alcohol is just knocking out your cortex and sedating you and that's not sleep the second problem is that alcohol actually fragment your sleep so you will wake up many more times throughout the night and that leads you to the next morning feeling unrefreshed by your sleep and unrestored the third thing about alcohol is that it's very good at blocking your dream sleep what we call rapid eye movement sleep or REM sleep for short and REM sleep is essential for both brain and body just as in as much as deep sleep is essential so on all of those three grounds alcohol is to be avoided even one glass with dinner we can demonstrate some of those effects now I want to be clear you know life is to be lived to a degree and I don't mean to be puritanical how you want to live your life is completely up to you what I want to do however is empower you with the knowledge of sleep science so that you can then make an informed decision as to how you would like to live your life the I think the politically incorrect thing that I would never say in front of a large audience is that you should go to the pub in the morning and that way the alcohol is out of your system by the evening and that way no harm no foul but I would never suggest that in in public so that's alcohol and that the second is caffeine I think everyone knows that caffeine kind of makes you more alert and makes you awake caffeine is a class of drugs that we call the psychoactive stimulants and it's by the way it's the only psychoactive stimulant that we readily give to our children without too much concern which i think is an issue but one of the other things that people don't know about caffeine is the duration of action so caffeine has what we call a half-life of six hours it has a quarter life of twelve hours in other words if you have a cup of coffee at noon a quarter of that caffeine is still swirling around in your brain at midnight so if you have a cup of coffee at lunchtime it's the equivalent of at noon let's say it's the equivalent of tucking yourself into bed at midnight and just before you do you swing a quarter of a cup of coffee and you hope for a good night of sleep and it's probably not going to happen so that's one of the other issues with caffeine the the final issue with caffeine I would notice that some people say I'm one of those who I can have a cup of coffee after dinner and I can fall asleep fine and I stay asleep so it's no problem there may still be a problem because if you give a person a standard dose of caffeine about 160 118 milligrams which is a standard cup and we've done some of these studies and then you measure their sleep that single cup of coffee will decrease and eliminate about 20% of your deep sleep so to put that in context to drop your deep sleep by 20% I'd have to age you by about 20 to 25 years or you could just do it every night with a cup of coffee I know I told you it makes me so often I'm so sorry about this recently I think comparing what they do in Japan what about food and when you should eat in terms of aiding a good night's sleep should we be eating a long time before we go to bed so the the relationship between sleep and food it's probably one of the most under researched areas what we certainly know is that first in terms of diet a diet that is high in sugar and low in fiber is bad for sleeeeep you typically don't sleep well that said a diet that's high in sugar and low in fiber is just about bad for everything but it is bad for sleep we certainly know that in terms of timing of when to eat you shouldn't go to bed too hungry but nor should you go to bed to fall so trying to stop eating by about sort of three hours or four hours before bed is is somewhat optimal you can find out what the sweet spot is and it's different for different people if you need a light snack keep it light nothing heavy not any of the heavy hitting carbohydrates you want to try and stay away from those two and also just trying to compress your feeding window into 12 hours or less it's called time restricted eating and it's been proven very good for weight management independent of sleep one of the things you talk about a lot in the book other particular hours of the night that are most important which are those if we aren't going to get the full eight hours which are the most important hours that we should be prioritizing cause I think we get that wrong so firstly I think there is this kind of mistaken belief that you know the hours of sleep before midnight or twice as valuable as there is after midnight that's nonsense so it it's really about getting both quantity and quality of sleep now you have many different stages of sleep in fact you have five different stages of sleep there are two broad categories non-rapid eye movement sleep and rapid eye movement sleep non REM sleep has been further subdivided into four separate stages and unimaginative Lee called stages one through four we're a creative bunch of sleep researchers of increasing in their depth of sleep so stages three and four are the really deep stages of restorative non REM sleep so you have these five stages and the question is which is more important and it's a hard question to answer but what we found is that every one of those stages of sleep supports some kind of function for the brain and the body and that makes sense because if any stage of sleep was non necessary you could imagine mother nature would have weeded it out and done away with it hundreds of thousands of years ago because sleeping is the most idiotic of all things from an evolutionary design you know when you're sleeping you're not finding food you're not finding a mate you're not reproducing you're not caring for your young and worst of all you're vulnerable to predation on any one of those grounds sleep should have been strongly selected against on all of them together it seems lunacy you know if sleep does not serve an absolutely vital function it's the biggest mistake the evolutionary process has ever made and what we've learned is that Mother Nature didn't make a spectacular blunder with this thing called sleep and it took 3.6 million years to put this necessity of eight hours of sleep in place and all of those stages are important there is a slight sort of experiment challenge that you can do though you can say which is more critical for your absolute life survival and they've done these studies with rats back in the 1980s and they were so shocked by the results that those studies will probably never be done again because they are unethical now firstly what they found is that rats will die as quickly from a sleep deprivation as they will from food deprivation it took the rats on average about 11 days to die from a lack of sleep the second is that then they did studies where they thought okay let's just remove rapid eye movement sleep or dream sleep and selectively deprive them of that type of sleep or selectively deprived them of deep non-rapid eye movement sleep and what they found was that the rats died almost as quickly from REM sleep deprivation as they did from total sleep deprivation they still died from non-rapid eye movement sleep deprivation from naanum preparation it just took them a little bit longer it took them about an extra five days before they died so all stages of sleep are necessary if you remove any one of them it is deathly is it definitely in humans well of course we can't do those experiments it's unethical but sadly there is a very rare genetic disorder that has given us that same proof and the disorder is called fatal familial insomnia it's a hundred percent genetically inherited disease it starts off with insomnia then it becomes severe insomnia then you cannot sleep all no amount of medication or tranquilizers that we have will put you to sleep and after about 18 months of no sleep the patient dies technology I'm going to move on to you next you're welcome by the way so I think many of us think that one of the reasons we can't sleep is its technology we're addicted to phones technology in our rooms but you do say in the book that the battle battle against technology is not what you actually want to advocate and we should unite with it can you can you explain that a bit yes so I think technology has certainly the invasion of technology into the bedroom has been the enemy of sleep you know people we have what's called sleep procrastination which is where you have your device at your bedside you're perfectly tied you could fall asleep but you think oh I'll just check Facebook one last time I'll just send that last email I should make that order on Amazon and then you look up and it's 30 minutes later and now you're deficient in by half an hour of your sleep it also causes anxiety and people will wake up they'll check their phones if they don't do that the first thing they do in the morning is swipe right and then this tsunami of anxiety washes in it's a terrible thing to train your brain to expect when you wake up in the morning and then blue light from these light emitting devices will block a hormone called melatonin at night and that will actually prevent healthy sleep so all of those things we know are documented and have harmed sleep but the genie of sort of technology is out the bottle and it's not going back in so to be puritanical about it there as well it's just not going to serve so I think what we need to do is work with technology and sleep tracking I think is a good example of this the sleep trackers that are out there right now they're not completely accurate they're not as accurate as my sleep laboratory you know I I wear one of these rings that tracks my sleep and people were wristwatches or head devices and I think that's good because in medicine what we typically say is what gets measured gets managed and simply having an awareness of something that you are usually non-consciously and for non aware of is a good thing can it in some people create sleep anxiety because you see that you're not getting enough yes it can and that's the trade-off but what that talk not technology will ultimately do is not only will we start measuring your sleep once we start measuring it we can start to then try to provide you tailored bespoke sort of sleep prescriptions for you the individual if you're having problems falling asleep that's a different set of advice that I would give you than if you're having problems staying asleep or if your bedtimes are very erratic that you're going to sleep you know late during the week and then sort of early during the weekend or vice-versa which is the majority of what most people do we can give you recommendations there too so we can close the loop and we can start to understand you the individuals specifically and give you the help that you need so I think and then we've got brain stimulation technology in older adults and those with dementia can we help people you know recover better from things like stroke because we know that sleep is critical for brain plasticity and brain rewiring that's another sort of target that we have of that brain stimulation device so I think technology is going to be the salvation of technology's ills against sleep ultimately I know that you work you said you work with lots of different groups but you work with sports men and women a lot and the effect that sleep can have on on sport and sports ability is huge tell us what's the optimal sleep and how can it affect your sporting ability yes so sleep is probably the greatest legal performance-enhancing drug that few athletes are abusing enough and you see it in some discreet athletes so Roger Federer claims to sleep around about twelve hours he does that with about ten hours at night and about a two hour nap during the day who's saying bolt the famous sprinter you slept somewhere between nine and a half to ten hours a night I believe one of the world and he takes naps strategically during the day and one of the world records that he broke he'd only been awake for about 35 minutes beforehand after sleeping and then came out and broke a world record they all know the power of sleep and they use it you know the basketball player LeBron James sleeps 12 hours as well and we work with all of these athletes so it's not just that sleep enhances your performance on the day I think where most sports teams neglect sleep they're starting to gain some aware of it awareness of it before the game or the performance it's after sleep I'm sorry it's after performance worse sleep is critical because that's where you need recovery and restitution of tissues so off when you're sort of performing at that high level you typically have chronic inflammation within the body and sleep is fantastic for reducing that chronic inflammation so your speed of recovery is markedly improved when you get sleep after a performance and most sports are daisy-chaining one game after the next so it's not just about performing on one single event it's about recovering and making sure that you can make it to the next game and the next game in the next game that's why sleep after every performance is just as important as sleep beforehand we also know that when athletes start to shortchange on their sleep bad things happen to them so if you're sleeping 6 hours or less as an athlete your time to physical exhaustion is dropped by 30% so in other words let's say you're training for a 10k run and then you have a bad night of sleep before the run you're now going to get exhausted by kilometer 7 rather than kilometer 10 next your peak muscle strength decreases your ability to expand or sort of exhale carbon dioxide decreases your ability of your lungs to inhale oxygen decreases even your body's ability to perspire effectively and cool itself while performing is also decreased when you're not getting enough sleep so just about every metric that we've looked at in the sports arena sort of decreases markedly in a linear fashion with less and less sleep and the final thing is injury risk we looked at a study where we took a group of athletes across a season and asked what was their injury risk and we've been tracking their sleep and then we bucketed those athletes into the amount of sleep that they were getting 9 hours 7 hours 6 hours 5 and there was a linear relationship the Leslie that you had the higher your injury risk when you were sleeping six hours or less you had an 80% chance of getting injured during the season if you are sleeping nine hours a night you were only think of 15 to 20 percent injury risk so marked difference and it's not just in sport of course that your productivity improves when you slept it's all across the board but as a sports man or woman you can sleep Usain Bolt's can sleep til 25 minutes before his race but most of us can't essentially bring up a boss and say you know what I'm going to be much more productive for you today I'm just going to spend another three days three hours it would be good three hours in bed before I come in you're advocating really a wholesale change of our culture and society in order for us to retain claim sleep but how can we how can we do that I am and I think you know it's not just within the individual that change needs to happen it has to happen at every level of society so let's start at right at the top of government levels I have never seen a major first world government have a public health policy regarding sleep why not we've got them for diet exercise risky behaviors drugs you know drink-driving where is that policy for sleep secondly let's take a step down and think about it within medicine you know doctors on average and the study just came out seven days ago on average across most curricula doctors will have only about one and a half hours of sleep education so less than 1% of the medical curriculum is you know concerned with sleep this is a third of your patients lives doctors and secondly that one third of their life asleep has such a manifold effect on their two-thirds of their life awake so why aren't we having you know those posters those informational posters around hospitals and in your GP surgery where it says you know best practices for not getting the flu don't sneeze you know cover your mouth why don't we have a chart that speaks about the harmful effects of not getting enough sleep and tips to get better sleep and part of the reason is that it's not doctors fault because they don't get in because they don't get enough education you know how are they supposed to know that sleep is this essential ingredient to a lifespan in a health span that's longer then I think we can take it down to a step of Education in schools you know I did a survey I remember back at my school I would have those lectures you know about sort of safe sex and drinking and drugs but nobody came in to tell me about the importance of sleep why not we should have that educational module in all schools as well and then finally at the level of the family what happens is that if you look at teenagers and their parents and you ask parents is your teenager getting sufficient sleep 72% of parents of teenagers say yes my teenager is getting enough sleep when in fact only 11 percent of teenagers are getting the sleep that they need and parents have this kind of sleep neglect and there's this parent to child transmission of sleep neglect where they chastise their child for getting sufficient sleep and you sort of get labeled as being slothful and then what happens is that when those children grow up they will repeat that same type of behavior to their children chastising sleep as a behavior so it has to happen at the government level at a magic medical level at the school level within the family level and then finally at the individual level talking about the school level I think you said you say that it's lunacy that they young have to get up so early for school is that something that should change to then it absolutely should do and the studies have been done there have been countless school systems and throughout Europe and also in America that have shifted their school start times and the data are very impressive firstly not surprisingly based on the data I just showed before academic grades increase but what we also found is that behavioral problems decrease truancy rates decrease and psychological and psychiatric referrals also decrease but there was something else that happened in this story of later school start times that we did not anticipate which is that the life expectancy of students increased and you may be thinking how does that work I don't understand it well one of the leading causes of death in late stage teenagers in most developed nations is not suicide that second it's car crashes and in one study in America I think it was Teton County in Wyoming they shifted the school start times from seven thirty five in the morning to nine to eight fifty five in the morning and then that following year they measured the change in road traffic accidents in just this narrow age range of sixteen to eighteen now the only thing that was more impressive than the one hour of extra sleep that those kids reported getting was the drop in car crashes there was a 70% reduction in vehicle accidents that following year to put that in context the advent of ABS technology anti-lock brake systems in cars that sort of prevents you from locking up under harsh braking that dropped accident rates by twenty to twenty five percent and it was deemed a revolution well here is a simple biological fact getting enough sleep that will drop accident rates by seventy percent so if our goal as educators truly is to educate and not risk lives in the process then we are failing our children in a quite spectacular manner with this incessant model of early school start times I want to get on to question or it's my last thing is about gender which I did not realize but is it true then that women suffer from insomnia and more than men yes sir the right now as I said sort of somewhere in between ten to fifteen percent of the population will suffer from clinical insomnia and that definition for clinical insomnia is actually very strict it's actually quite hard to get that diagnosis your sleep problems have to be quite severe and in fact I think that that criteria should be lowered because a lot of people are struggling and not getting the help because they can't exceed that threshold to get a diagnosis that aside we know that insomnia rates are twice those in females than they are in males so women will suffer far greater rates of insomnia when it comes to sleep apnea a snoring it's the opposite twice as many men girls will suffer from sleep apnea than females so there is a different distribution for different sleep disorders I think I must extend the conversation out to you and I knew lots of hands will try out would take questions in pairs and try and get through more that way so it's just this - oh okay they're gone yes and if you go first and then if you've got to make someone thank you my question is about the early years of childhood where mothers tend to be extremely malnourished and sleep and don't really have much of a choice in that regard and that must be an evolutionary byproduct to some extent so what do you tell all the sleep-deprived young mothers sleep-deprived mothers and then where's the other mic hi yep my question is well I work for the NHS and I find it very difficult to explain to my colleagues about the sleep depth that you mentioned earlier and they just say oh you know they do for our for ships in a row in a week and they say they sleep it off the next on the day off how I don't know how to explain it that you carry that depth could you just sort of mention it explain yes so I'll let me start with this question to begin with we know that shift workers because of their disrupted sleep firstly if they're trying to sleep during the day or sleep at other times that are non-optimal relative to their sort of own predilection so everyone here has what's called a chronotype are you a morning person or are you an evening person or somewhere in between you don't get to decide it's genetically hardwired and predetermined from birth and there's very little that you can do in terms of wiggle room and so if you're sleeping at a place that's mismatched on the sort of 24-hour clock face you will suffer reduced quality of sleep and reduced quantity of sleep especially if you're doing shift work and that's the reason that the World Health Organization has classified nighttime shift work as a carcinogen we also know it doesn't stop at cancer we know that shift workers have far higher rates of diabetes for high rates of cardiovascular disease as well as stroke and also they're far more likely to have excessive weight and all be obese and so the evidence there in terms of having that mismatch is very clear now what do we do about that a society well it's very difficult because you know if I have an appendicitis at four o'clock in the morning I'm desperately grateful to the people who are working there and who are going to save my life but I think we can think more strategically about it you know if we've got we know the krona type of people if you're an extreme evening type then maybe it's easier for you to work the night shift if you're an extreme morning type maybe you should come in and replace them at four o'clock in the morning because it's easier for you to get up at three o'clock to make that four o'clock shift so we can be biologically more strategic to help that situation until something else comes along a technology that helps sort of advances where we can start to gradually throttle back on that type of brutal work but it is brutal and it has consequences and those consequences are well known the other brutality is parenting so we know of course that that's one of the times in life where sleep gets very unpredictable sleep gets very short the recommendations are tricky firstly sleep opportunistically asleep whenever you can try to get it whenever there is the opportunity at that time in life if you are lucky enough to have a partner and you're co-parenting then trying to think about having a shift system again think about your are you of the evening type so you can take sort of you know the first half of the night because you don't mind staying up late and then the morning type takes over the morning shift so think about trying to hand off just strategically in that way then for your child there are a couple of tips as they get older the first just like adults regularity set up a routine and do not deviate from that routine your body loves regularity and even your child's body even though it doesn't yet have a strong circadian rhythm it still likes regularity and will respond well to it finding a winddown routine before bed whether that's reading or doing a jigsaw puzzle seems to help there's a great study published just a couple weeks ago from Sheffield where they did this intervention with kids and they increased sleep in kids by about two hours by firstly keeping things regular having a winddown routine also taking toys out of the bedroom because toys tend to be a trigger a cue for activation for fun for being excited so making the sleep environment a calm sleep environment and then finally getting your child to get daylight during the day especially in the morning and being physically active if you combine all of those things together you ensure the greatest likelihood of good sleep in your child gentleman here you touched on this briefly earlier but how robust is the the science and I guess the research around sleep or lack of sleep as a risk factor is factor for developing something like Alzheimer's disease hi could you talk a bit about how SSRIs might interact with sleep and affect sleep particularly because for instance when people come off SSRI sometimes they give incredibly vivid dreams and increased REM activity and I just wonder if that's a concern for you about the the use of SSRIs and and their effect on sleep yes so I'll take the the Alzheimer's question first yeah I don't make that statement sort of flippantly but insufficient sleep is probably the most significant lifestyle factor determining whether or not you will develop Alzheimer's disease at this stage and that evidence is causal if it was just associational I'd be so bullish but we now have causal demonstration so in mice if you sleep deprived them for one night you get an immediate buildup in the sticky toxic protein called beta amyloid in the brain and recently they did the same study in humans where they actually deprived them of deep sleep and I'll come back to why it was deep sleep in a second and then they did a spinal cord puncture and then removed the spinal fluid which picks up the amount of toxic protein that's circulating in the brain it's a proxy for that and even after just one night of decreasing deep sleep you saw an increase in the amount of beta amyloid circulating within the spinal fluid both of those are causal pieces of evidence both of those happen after just one night it's quite striking why is that the case the reason is that about five years ago a team at Rochester University in in America made a landmark discovery what they found is that you have a sewage system in the brain now everyone's familiar with the sewage system of the body it's called your lymphatic system well we never thought that the brain had one but it does it's called the glymphatic system after the cells that make it up called glial cells and at night that sewage system kicks into high gear and in fact you get about a 20-fold increase in the cleansing of the brain when you go into deep sleep so it's sort of like good night sleep clean as it were and if you don't get that cleaning of the brain you don't wash away that sticky toxic protein so every night that you're short sleeping you're increasing the deposition of this toxic beta amyloid every night you're not sleeping you're increasing your Alzheimer's disease risk and that's why now we can look back on those epidemiological studies that show that people who are short sleeping are far more likely to have greater amounts of beta amyloid in their brain and more likely to also develop Alzheimer's disease and we're now just finding the same evidence for the other protein culprit that underlies outsiders disease which is called tau protein so both of those now have sleep links the question about SSRI is is an interesting one they're called serotonin reuptake inhibitors or selective serotonin reuptake inhibitors they do seem to disrupt sleep some people have used them off-label as a sleep prescription medication because it does seem to help some people with vers sleep it may be because in part it's an anxiety that it reduces anxiety and allows sleep to sort of break through a little bit easier however we do see that it disrupts rapid eye movement sleep and rapid eye movement sleep it turns out is critical for your mental health rapid eye movement sleep is essentially emotional first aid and if you're disrupting that rapid eye movement sleep you may be disrupting some of those mental health benefits we don't really have the causal studies that inform us yet to suggest that we shouldn't be using those but certainly we know that SSRIs disrupt the natural cycles of sleep back in the middle and what I miss miss lady there after you as well yeah okay you want to go first yeah yeah is it a problem if we sleep too much if you just raise your hand is it a problem if we sleep too much and hi I have a blood condition which means I'm prone to clot after reading your book I did a little experiment where I plotted mark the thrombotic events the blood clots I'd had in my life and then on tracing paper I plotted the sleep deprivation and sleep disruption when I put the tracing paper over the top of the blood clots I had a perfect match have you done any official research that's not my mickey mouse research into the correlation between thrombotic events and sleep deprivation or disruption we have lots of other people have done that work too and we know that once you start getting below seven hours of sleep the clot risk increases we also know that's true for even something like calcification of the coronary arteries those studies have been prospective longitudinal studies they've been very well controlled for we throw everything in there that is an Associated factor your body mass index your smoking history your exercise history your age and even with all of those factors considered sleep Maine's a statistically significant predictor of those things we've got some data that is as yet unpublished but as long as you don't go out and tell anyone about it we are we've just found a link between an fragmented sleep or poor quality sleep and atherosclerosis so sort of the hardening of the arteries and what was interesting is that it wasn't a direct effect of sleep it was that you're fragmented sleep triggered an increase in the inflammatory white blood cells in your body and those inflammatory white blood cells were causing the hardening of the arteries that plaque buildup in those arteries so it's this sort of vicious chain of command it's like the finger that flicks the Domino is bad sleep that leads to long-term chronic inflammation which predisposes you to atherosclerosis so in that whole realm of cardiovascular disease it is very well correlated now and many of those studies of causal both through animal experiments and also longitudinal experiments which are pseudo sort of correlational causal and then his question can you sleep too much can you sleep too much it's a fantastic question there is such a thing called hypersomnia excessive sleep where we typically see that is in patients with depression but if you look at that data it's actually that patients report staying in bed longer rather than sleeping longer because they just don't want to face the world it's called anhedonia it's a feature of depression that you so you just stay in bed you don't want to get out into the world but let's play with that question a little bit more let's just go with it theoretically is there such a thing as too much sleep well I actually think yes there is and that may sound strange coming from someone like me but rest assured that it's the same thing for the two of the vital ingredients of life which is food and oxygen and even water you know can you can you overeat yes you can can you actually over hydrate it happened in the 1990s with the ecstasy craze governments were saying you need to hydrate at clubs people drank too much water they had high blood pressure and they had stroke and cardiovascular events can you get too much oxygen yes you can actually have hyperox emia which actually damages brain cells because of free radical damage so it's a u-shaped function there's a sweet spot for everything is sleep a similar u-shaped function I actually think it probably is that probably is such a thing is too much sleep are most people in the modern world in danger of getting too much sleep Oh contraire I'm gonna take two more then you can all go straight to bed this lady here that's just yeah with your hand up high just behind you okay you you yes you did yep and then okay thank you so I also wear a ring like yourself it's the aura and track my sleep and my question is if you're looking at the amount of deep sleep and REM sleep that you're having I know you saying that it can go down as you progress through life what should you be aiming for in terms of the percentage of deep sleep the percentage of REM sleep and the cycles you go in thank you I am considering the different chrono types I'm a teacher so I wanted to know what you think is the optimal time that teenagers should be starting school so the optimal time based on the evidence is probably around 10 o'clock 10:30 in the morning and again this is not their fault as you go through adolescence there is a shift in your biological rhythm that fast-forward to you in time so you want to go to bed later and wake up later we don't quite know why it happens I think I write in the book about one theory which is that it helps these teenagers essentially you know dislocate themselves from their parents and start to develop on their own within their own social circles so they start to go to bed later than their parents actually I think it's a clever way to do that but right now based on the data about 10:00 or 10:30 in the morning and the question then becomes well let's not start schools at different times for different pupils there are harm on younger kids starting later and if you look at the data young kids they're better at starting earlier because they're naturally waking up earlier but if they start later they don't learn any less so there's no damage to them to start later but there's a huge benefit for older kids to start later and therefore I think we need need to make that change and you know there's been bills put forward here in government for a 10:00 a.m. start time and I would rousing ly support that when sleep is abundant Minds flourish when it's not they don't and so the question about the the aura ring or the sleep tracking devices in general the first thing I would note is that they're not entirely accurate right now for separating sort of deep sleep from light sleep from REM sleep they're not bad in terms of figuring out whether you've been awake or asleep but once you get into those different stages their accuracy is about 60 to 70% so you may not want to necessarily trust them will they get there in the next two to five years I think probably they will but it's not the accuracy that I can get in my laboratory in terms of your sort of sleep ratios you should probably be getting about 20 if you're a sort of you know a young healthy person and we're talking you know 20s to 35 this is the optimal ideal sleeper probably deep sleep about 20% 22% REM sleep about the same 22 to 25 percent and then the rest of it is lighter non-rapid eye movement sleep which is actually important light non REM sleep isn't non-functional it does support several functions too just like we said all stages of sleep are important but that's what you should be aiming for I think we've all learnt an extraordinary amount thank you very much for coming and mesons thank you very very welcome thank you thank you so much thank you

Channel: How To Academy Mindset

Views: 211,008

Rating: 4.8798718 out of 5

Keywords: Matthew Walker, Why We Sleep, Why We Dream, Hannah MacInnes, marijuana, Alcohol, napping, Joe rogan, berkeley, REM sleep, sports, revision, cannabis, caffeine

Id: 5j9xCC_VtQA

Length: 68min 21sec (4101 seconds)

Published: Fri Jun 28 2019