Why Sleep?: Matthew Walker's CNS 2019 Keynote

good afternoon on behalf of the program committee it is a pleasure to welcome you to San Francisco and to the 2019 meeting of the cognitive neuroscience society of course San Francisco is a beautiful city in which to have this meeting and I hope that at some point perhaps over the lunch break so the coffee breaks you'll have a chance to step outside of the conference walls and actually enjoy some of what the city has on offer San Francisco is also also a city that is known for its bridges and so I always find it apt that it is a city that we come back to so often for these CNS meetings because of course CNS really is a society that is about bridging different approaches toward understanding human thought about integrating the psychological the computational and the neuro scientific approaches it's also a society that's about bridging continents bringing together scientists from around the world who seek to challenge one another to invest in one another's ideas and to push each other to rigorously test their hypotheses and I know that since the time that I was a graduate student and first started coming to these meetings I've really appreciated that CNS is also a society that tries to bridge scientific generations it brings together trainees those that are brand new to the field or perhaps still figuring out if this is the field of study for them and it puts them in contact with the founders of the field with people that have made seminal contributions to the study of human thought and so again I think it's really fantastic to keep in mind these bridges that were forming here in the beautiful city of San Francisco the interdisciplinary approach was certainly on full display earlier today for those of you who were able to attend the outstanding Data blitz talks by our trainees and to see the wide array of fabulous research being conducted in the poster session and later today the panel discussion on the relation between psychology and neuroscience will once again zoom in on the benefits and also the challenges of trying to integrate across psychological and neuro scientific approaches so with this in mind it's especially exciting to introduce dr. Matthew Walker as this afternoon's keynote speaker dr. Walker is professor of neuroscience inside ecology at the University of California at Berkeley he's also the founder and director of the Center for human sleep science he earned a degree in neuroscience from Nottingham University in the UK and his PhD in neurophysiology from the Medical Research Council in London and prior to beginning his professorship at Berkeley he held faculty appointment at Harvard Medical School dr. Walker's research team really does embrace this integrative approach toward research investigating the role of sleep using brain imaging methods including MRI and PET scanning high-density EEG recordings of sleep genomics autonomic physiology brain stimulation and cognitive testing they bring all of this together in order to try to understand the importance of sleep for our everyday life now his website actually states that his research teams motivating goal is working toward understanding quote everything about sleeps impact on the human being from birth to death in health and in sickness so that's a gargantuan task but certainly he's up to it and he's chipping away at it building this understanding piece by piece to date he's published over 100 scientific research studies and the wide reach of his research into the effects of sleep really becomes apparent when you read and look at the scope of his writings so just a few examples include a nature neuroscience article on the sleep deprived human brain a neuron paper titled sleep and human aging and an article in the annual review of clinical psychology on the role of sleep in emotional brain function so he clearly appreciates the need to bring together a lifespan developmental approach an effective and social approach and a cognitive approach to really understand the impact of sleep furthermore as I think he'll discuss this afternoon he also really sees the importance of understanding the connections between the brain and the body and leveraging those complex interactions to fully understand the importance for sleep in our waking lives dr. Walker is widely recognized for his research having received funding from the National Science Foundation the National Institutes of Health he's a CAV leaf L O of the National like me of Sciences he's also venti featured on many television and radio shows including CBS 60 minutes the National Geographic Channel and the BBC he's asleep scientist at Google and he served as an industry consultant to many companies so in this regard dr. Walker really embodies the spirit of this public lecture insofar as he firmly believes that scientific discoveries should not stay hidden in the pages of scientific journals but should be shared broadly and communicated clearly to all stakeholders and of course when it comes to understanding the importance of sleep the stakeholders are many all of us in this room and the stakes are incredibly high he does a compelling job outlining these stakes in his best-selling book why we sleep and I expect that he'll be sharing many of these insights with us this afternoon now as a sleep researcher dr. Walker may be among the precious few speakers who may not become offended a few doze off during his talk this afternoon but I predict that this is actually going to be a riveting talk that is going to keep you awake engaged and learning throughout so even if you're feeling some jetlag perhaps save that nap for after his talk when you can consolidate all that you've learned it is really a distinct pleasure to welcome dr. Matthew Walker to the podium to give us his answer to the question why sleep well it is a delight and a privilege to be speaking with you and thank you to Elizabeth for such a wonderfully kind introduction I don't know if I will match up to the expectation I'm also very humbled by the number of people from the general public who have come along to listen to the talk as well so thank you for that with all of that said I would like to start 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 virility 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 today from this point forward it's only going to get worse I'm also going to tell you about the alarmingly bad things that happen when you don't get enough both for your brain and for your body and 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 and future-proof that information within your brain but recently we've discovered that you not only need sleep after learning you also need sleep before learning and now to actually prepare your brain 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 memories let me show you the data here so here in this study we decided to test the hypothesis that pulling the old nighter was a good idea so we took a group of healthy adults and we assign 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 shut-eye but the deprivation group we're going to keep them awake in the laboratory under full supervision there's no naps there's no caffeine by the way it's miserable for everyone involved and then the next day we're going to place those participants inside an MRI scanner and we're 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 the efficiency of learning so the higher up you are the more that you learn and when you put those two groups head-to-head what you find is a quite significant 40 percent deficit in the ability of the 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 I'm just a frame that in context it would be the difference between acing and exam and failing it miserably 40% and we've gone on to discover what actually goes wrong within the 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 could think of the hippocampus like the informational inbox of your brain in that it's very good at receiving new memory files and then holding on to them and when we looked at this structure in those people who'd had a full night of sleep 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 as almost as though sleep deprivation had shut down the memory inbox and new incoming files they were just being bounced you couldn't effectively commit new experiences to memory and if you'd like to know what life is like by the way without a functioning hippocampus and just watch the movie memento I'm sure a lot of you have seen it this gentleman serviced brain damage and from that point forward he can no longer make any new memories he's what we call densely a music 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 happens if i take sleep away but let me just come back to the control group for a second remember those folks that got a full eight hours of sleep well we can ask a very different question here 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 deepest stages of sleep that have riding on top of them these spectacular bursts of electrical activity called sleep spindles and it's the combined quality of these deep sleep brainwaves that act almost like a file transfer mechanism at night shifting memories from a short-term vulnerable reservoir to a more permanent long-term storage site within the brain that prevents you from forgetting and it is important that we understand what it is during sleep mechanistically that is actually transacting these memory benefits because there are real medical and societal implications and let me just tell you about two areas that we've moved this work out into I'll start with medicine and specifically the topic of Aging and dementia because I think many of us have a sense that as we get older our learning and memory abilities begin to fade and decline it's harder to learn it's harder to recall and retain but what we've also known for a long time is that a physiological signature of aging is that your sleep gets worse and not just any type of sleep by the way especially that deep quality of sleep that I was just discussing and only last year we finally published evidence that these two things are not simply co-occurring they are significantly interrelated and it may suggest 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 all of that is remarkably depressing news it's in the mail it's coming at you if it's not already there but there's a possible silver lining here because unlike many of the other factors that we know are associated with aging in dementia 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 a medicine has no good wholesale approaches right now but that sleep is a missing piece in the explanatory puzzle of aging and 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 unfortunately they are blunt instruments that 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 evidence during the the Q&A instead we're actually developing a method based on this it's called direct current brain stimulation and sounds a little bit like science fiction but it's actually science fact your apply electrode pads to the head and you insert a all amount of voltage into the brain so small that you may not even 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 you 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 could we restore back some healthy quality of deep sleep and in doing so can we maybe Salvage aspects of their learning and memory function that is my real hope now that's one of our sort of moonshot goals as it were so by the way I always get asked the question people say where can i buy one of those devices I want one yesterday I want five more tomorrow and they are not yet fda-approved for sleep you can buy them online I strongly advise against that you can just go onto YouTube people have misaligned the voltage the skin burns they've lost their eyesight for several days don't don't do this we are desperately trying to bring this to fruition as soon as possible so that's sleep and memory in medicine in the context of aging but let me now speak about sleep and memory in society because if sleep truly is so essential for learning then increasing it in a context where it matters most such as education should prove transformative and it has because there are several school systems throughout the United States that have begun to delay their start times so that kids can sleep longer and then they've looked at the academic outcome one of the earliest test case examples happened in Minnesota and they shifted their school start times from 7:25 in the morning to 8:30 in the morning and then by the way what are we doing trying to educate on next generation at 7:25 in the morning to give you a sense of that school buses for a 7:25 start time maybe start leaving at 5:30 in the morning that means that some kids may be waking up at 5:15 5 o'clock even earlier this is lunacy but here in Minnesota it was the beginnings of a movement and the measure that they looked at was actually this it's called SAT scores this is for those who don't know this is a standard university entrance exam here in the United States and in the year before they made the time change when kids were going to school at 7:25 in the morning the average SAT score was 1288 now that turns out to be a respectable score the following year when kids were going to school at 8:30 in the morning and getting more sleep the average SAT score was 1500 that is a 212 point increase which is non-trivial that may change which tier of university those kids go to and ultimately perhaps their subsequent life trajectory now some people have questioned aspects of the Minnesota study and I think for good reason but in all of the Curley controlled reports to date the findings are unequivocal academic grades increase behavioral problems decrease truancy rates decrease and psychological and psychiatric referrals also decrease but something else happened in this story of latest school start times and it was something that we did not anticipate the life expectancy of students actually increased and you may be thinking I don't understand how how is that possible the leading cause of death in late-stage adolescent teens in most developed nations is not suicide that's actually second it's this road traffic accidents and here sleep matters enormous Lee so another example comes from Teton County in Wyoming they shifted their school start times from 735 to 855 and the only thing that was more remarkable than the extra one hour of sleep that those kids reported getting was this there was as a consequence that following year a if I can get it to work again there was a 70% reduction in vehicle accidents that following year just to to put this in context for you as as they're bringing this down the advent of ABS technology in cars anti-lock brake systems that prevent your wheels from locking up under hard braking so you can still maneuver that dropped accident rates by about 20 to 25 percent and it was deemed a revolution well here is a simple biological factor getting enough sleep that will drop accident rates by up to 70% I think we need to radically reconsider the importance of sleep in education because when sleep is abundant Minds flourish and if our goal as educators truly is to educate and not risk lives in the process then I fear that we are failing our children in a quite spectacular manner with this incessant model of early school start times so that sleep for learning memory aging Alzheimer's education what else is sleep good for let me tell you that sleep is essential to help stabilize and I'm sorry it's completely stuffed now so I don't quite know next slide ok thank you very much sleep is essential to actually help stabilize your emotional and mental health and without sleep the emotional circuits of your brain can become hyperactive and irrational and allow me to demonstrate with a sleep-deprived subject next slide because it turns out that we do video diaries with our participants throughout the deprivation night and you go to meet one under the pseudonym of Jeff and Jeff has just entered the study it's 11:30 at night on day one he's been awake for a perfectly normal 16 hours and let's hear from Jeff what his sort of hopes and aspirations are for the deprivation period next slide 27 right now I've been here for about and think about an hour know yeah about an hour so it's the first hour I'm reading my paper right now 30 page paper hopefully I can get some of it done before I get too sleepy so that's Jeff a perfectly likable affable chap who's hoping to get his 30 page report complete in a night of sleep deprivation classic delusional undergraduate thinking I have to say I see it all of the time in my students so so sorry so now let me fast-forward the clock it's now 5:30 the following morning Jeff has now been awake for 22 hours straight and instantly you'll notice one of the hallmark features of sleep deprivation which is that you actually slide down in your chair Jeff's just look around the room I know Oh Jeff is down about six inches here now it's about an inch for every hour that you've been awake beyond the standard 16 and based on our highly sophisticated machine learning algorithms but in all honesty noticed just how emotionally different Jeff has become and some people have rather unkindly described him as becoming a little bit emotionally unhinged so let's let's hear from Jeff how that 30 page report has been going and and I do apologize ahead of time for the profanity I'm very angry right now because I didn't get any but I curse others [Laughter] so that you notice how Jeff went from being remarkably upset and annoyed that he got none of his 30 page report complete so then finding it almost hilarious he was almost sort of punch-drunk did he on sleep deprivation and then came right back down to baseline again that is a remarkably abnormal emotional distance to travel with in such a short time period and I think it emphasizes the type of destabilizing influence that a lack of sleep has on our emotional integrity and we've gone on to discover what actually changes within the brain to produce this type of pendulum like emotional irrationality and there's a structure that sits very deep within the brain next slide um next slide called the amygdala and you can see it here in the red colors and the amygdala is one of the centerpiece regions for the generation of emotional reactions including negative reactions and when we looked at this structure in those people who'd had a full night of sleep next slide here in green we saw a nice controlled modest degree of reactivity yet in those people who were sleep deprived we saw this amplified almost aggravated degree of responsivity in fact the amygdala was almost 60 percent more reactive under conditions of a lack of sleep it's almost as though without sleep we become all emotional accelerator pedal and too little regulatory controlled break as it were but what was more concerning perhaps to us was that this represented a neurological signature that was not dissimilar to several psychiatric conditions next slide and we've gone on to discover links between sleep disruption and disorders such as depression anxiety in reading PTSD schizophrenia and tragically and most recently suicide as well in fact over the last 20 years we have not been able to discover a single psychiatric condition in which sleep is normal so I think sleep may have a significant story to tell in both our understanding our treatment maybe even ultimately contributing to our prevention of grave mental illness that's another one of our hopes as well so that's sleep for your brain but of course sleep is just as essential for your body and here I could have gone into any one of the model systems in detail and we've already spoken a little bit about sleep and the 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 that is 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 in the fall when we gain an hour of sleep we see a delightful 21% reduction in heart attacks that's how fragile and vulnerable our bodies are to even just the smallest perturbation of sleep I think many of us would think nothing about losing an hour of sleep but as a deeper dive I would like to focus on this sleep loss and your immune system next slide and here I want to introduce these delightful blue elements in the image next slide they are called natural killer cells and you can think of natural killer cells like The Secret Service agent of your immune system they are very good at identifying dangerous foreign elements and eliminating them and what they're doing here is embedding themselves into a malignant a cancerous tumor mass and destroying it so what you want is a viral set of these immune assassins at all times and sadly that's what you don't have if you're not sleeping enough next slide so here in this study we're not going to deprive you of sleep for an entire night you're simply going to have your sleep restricted 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 next slide it's not twenty percent in fact what we see is a 70 percent reduction in natural killer cell activity that is perhaps a concerning state of immune deficiency and it happens essentially after one short night of sleep imagine the state of your immune system after months if not years of insufficient sleep and it should come as no surprise then to learn that we are now discovering 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 has now become so strong that recently the World Health Organization decided to classify any form of nighttime shift work as a probable carcinogen in other words 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 and being quite serious now it is mortally unwise advice because 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 this is what epidemiological studies teachers across millions of individuals the shorter your sleep the shorter your life short sleep predicts all cause mortality and the challenging news keeps coming because if you are fighting a battle against cancer and not getting sufficient sleep that cancer may grow more quickly and aggressively so here I want to focus work not from my own sleep center but that of a scientist called David goes out who works at the University of Chicago and he looks at the relationship between sleep loss and cancer in mice now I know this type of work isn't necessarily for everyone and I will tell you when to look away at the time that's right if you had prefer to do so but in one of the studies he took a group of mice and he inoculated them with some cancer cells on the back and then he gave that cancer a one month period to grow and at the end of the one month he resected the skin and then he measured the size of the tumor mass now half of the mice were allowed to sleep normally during that one month gestation period the other half had their sleep restricted not total deprivation just limiting their sleep a little bit morning and evening so I'm going to show you a video that describes the results and now would be the time to look away if you would prefer to do so so here you can see David pointing to a monitor with a mouse in on the screen and you can see the skin resected there and you can see that tumor mass quite clearly this is in one of the mice that was allowed to sleep normally during that one-month period in a second I'll play the video and he will reveal behind it another Mouse and that Mouse was in the sleep restriction group and you will see the difference this is the difference there was a 200% increase in the size and the speed of that cancerous growth caused by insufficient sleep were still the cancer in those underslept mice had actually metastasized now that's just a medical description meaning that the cancer had breached the original origin and started to invade other areas organ bone as well as brain and it's when cancer becomes metastatic that we see mortality rates escalate so if you are fighting a battle against cancer and not getting sufficient sleep it may be the equivalent of placing gasoline on an already aggressive fire sleep loss acts like an accelerant and we now know that it produces a harmful biological fertilizer for the more rampant and rapid growth of cancer now if increasing your risk for the development of Alzheimer's disease or cancer were not sufficiently 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 again you're not going to have your sleep deprived for an entire night they took a group of healthy adults and limited them to six hours of sleep next slide for one week and then they measured the change in the gene activity profile relative to when those very same subjects were getting a full eight hours of sleep and there were two critical findings next slide the first was that a sizeable and significant next slide 711 genes were distorted in their activity caused by a lack of sleep and by the way that lack of sleep is relevant we know that almost one out of every two adults in developed nations is trying to survive on six hours of sleep or less during the week the second result was that about next slide and half of those genes were actually increased in their activity caused by a lack of sleep the other half were actually decreased those genes that were actually switched off or downregulated as a consequence of a lack of sleep next slide were numerous genes associated with your immune system which again fits very well with the data I was just describing even here at a genetic level you can see that immune deficiency those genes that were actually up regulated or what we call overexpressed next slide were genes that were associated with the promotion of tumors genes that were associated with long term chronic inflammation within your body and finally genes that were associated with stress and as a consequence cardiovascular disease now I think many individuals in society feel uncomfortable next slide about the idea of genetically modified embryos or even genetically modified food but by choosing to get insufficient sleep I think we may be forced to accept that we are performing a similar genetic manipulation on ourselves and if we don't let our children get the sleep that they so desperately need then we may be inflicting an unwitting similar genetic engineering experiment on them as well there is simply no aspect of your wellness that can retreat at the sign of sleep deprivation and get away unscathed it's a little bit like a broken water pipe in your home in that 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 so where does this leave us then what is the piece of mental furniture next slide that I would like to gift to you as we finish this talk well it would be this sleep unfortunately is not an optional lifestyle luxury next slide sleep is a non-negotiable biological necessity it is a life support system and it is mother nature's best effort yet at immortality I believe it is now time for us to reclaim our right to a full night of sleep and without embarrassment or that terrible stigma of laziness and in doing so we may finally be reunited with that most powerful elixir of life the Swiss Army knife of health as it were and with that soap box rant over I will simply say good night good luck and above all I do hope you sleep well thank you very much indeed thank thank you very much I'm more than happy to take questions I think we have plenty of time there are microphones I think in either side of the runway it's not a runway it's it's a way yes thank you so much first of all I was wondering about the upper limit of the sleep so we're now sure that when instructor our life is shorter what about longer than 8 hours sleep yeah it's a good question I think so the question is about how long is maybe too long for sleep is there such a thing as too much sleep there is a condition called hypersomnia where we typically see that in people with depression now if you look at that data it's actually it's not clear that those people are actually sleeping longer if you look at the results and you dig into them people seem to be staying in bed longer so therefore it may be masquerading as what we call hypersomnia so that's unclear but let's just kind of go with your idea for example could there be such a thing as too much sleep I actually think yes there could but don't make any mistake about it it's the same for the three other critical ingredients of life which is food water and oxygen can you get too much oxygen yes you can and you can actually have free radical damage with hyperox emia can you overeat yes we of course know that too can you actually take on board too much water it happened in the 1990s with the ecstasy craze where people were drinking too much they increase their blood pressure so much that they had cardiovascular stroke and heart attacks so can you get too much sleep well we haven't really discovered such a thing yeah but I believe that probably is I suspect it follows exactly the same u-shaped curve law are most people in danger of getting too much sleep oh contra yeah thanks amazing talk so I had a question about the Minnesota data so you presented improvements in SAT scores which I think I could understand why just any more would improve your health and learning but typically SAT prep and those sorts of like what's on the test is not usually taught in schools so I was curious why you presented on that and not maybe they also saw improvements in academic achievement on the test they're taking in school not necessarily people may care more about but you would think if it's about learning the things that you get during the school day then it would be also the grades yeah another great question so that data is there so if you look at general academic performance of classes in school you see the same data that when you shift school start times those grade point averages also increase what's also interesting however is were that grade point increase for the in class in school data is coming from they're not changing their performance in the afternoon classes those grades actually stayed the same where are they improving it's in the morning hours that's where you see the spike if the trip and it's an astronomical spike because it's sort of you know when you average it out across the day it's still significant but where it's happening most is in the early morning hours and I think for two reasons firstly because they're getting more sleep so the brain is just more capable overall but also the second thing is that they're just half asleep you know they are not biologically designed especially teenagers at that time of morning to be absorbing any information certainly let alone have any good grace you know having a teenager awake at 7 o'clock in the morning is like having you know an adult awake at 4 o'clock in the morning of 5 o'clock in the morning you know no you wouldn't be the best form of yourself would you at 4 o'clock in the morning well teenagers aren't either at 7 o'clock thank you yeah I wanted to ask the flip side of the question that you yeah why are we sleeping why don't we sleep I mean it seems relevant because yeah you want to something's preventing us from doing this it's manifestly good for us it is and it's a great question because strangely enough human beings are the only species that deliberately deprive themselves of sleep for no apparent games and but when you actually assess why we are not sleeping it turns out that there isn't one single answer there's a whole constellation of different factors that have come - almost like a perfect storm in modernity the first is that were working longer hours the second is that typically were commuting for longer which together means that people are leaving the house earlier and arriving home later when they come home they typically don't want to sacrifice television time or family time so the one thing that gets squeezed like vise-grips in the middle of the night is this gelatinous mass called an eight-hour night of sleep but that's not the only problem the next issue is that we've got things such as anxiety which is trigger of insomnia we've never seen higher rates of insomnia than we have right now and in part that's underlied or undergirded by this spike that we're seeing in anxiety disorders the next thing is an increased use of sleep aids such as alcohol alcohol is anything but a sleep aid it is a disaster for sleep but people are using it as an over-the-counter remedy for their insomnia which makes their sleep worse finally well not finally but there are other reasons caffeine is now the second most traded commodity on the surface of the planet after oil and caffeine is no friend of sleep if you look at the astronomical rise in the number of Starbucks coffee houses over the past 50 years and I've plotted this from the Financial Times that tells you everything about why we perhaps aren't sleeping necessarily so good either I think we are wired and tired in this generation to finally sleep has an image problem it has a stigma associated with it which is what I described and people now have almost this sleep machismo attitude some people do not all but some people do it's sort of a braggadocio of how little sleep that we're getting a lot of people will come to me at the end of talks and they will wait and they will shamefully say to me ugh one of those people who need eight hours of sleep a night so I think the societal forces I think there are pragmatic forces I think there are chemical forces all of which have come to a collision that are causing this great sleep depression and it is 1942 the average American was sleeping seven point nine hours a night now that number is down to six hours and 31 minutes I'm happy to believe a Starbucks thanks can taking naps psychological and physiological effects of sleep deprivation so naps don't seem to be able to necessarily ameliorate the deficits can naps give you some benefits though and the answer is yes and we've done a number of studies looking at this that naps can sometimes give you almost as much benefit for things like learning and memory as a full night of sleep and I would say though that two things firstly the naps that we use are not really power naps they're usually 90-minute naps because we try to get a full cycle of sleep and a human sleep cycle is about 90 minutes so it's probably a little bit different to what most people use the second issue with naps is that there are a double-edged sword and when you are awake during the day you're building up something called sleep pressure it's a chemical in your brain called adenosine the longer that you're awake the more of that chemical that builds up the sleepier you feel after about 16 hours of building up that adenosine that sleep pressure you should be able to fall asleep and stay asleep and when we sleep we remove that chemical that adenosine so we release the pressure valve on the cooker and we sort of clear it away and we wake up refreshed so the danger with naps is that if you take them or if you take them too late in the day you actually take away you relieve that pressure valve and you release some of that healthy sleepiness that you've been building up and then when it comes time to fall asleep in the evening you either can't fall asleep or stay asleep so the advice is if you're struggling with sleep don't nap or if you can't nap regularly you probably shouldn't nap either but do naps provide a physiological benefit yes they do but on naps like the bank where you can sort of you know accumulate a little bit of and then spend it off when you're going to face the debt and the answer is no unfortunately sleep is not like the bank where you can't accumulate a debt and then spend it off at a later point in time first I want to say thank you for being on your soapbox your TED talk changed my life for the better all of my students watch it regardless of what course they're in or how much they care thank you thank you my question is how can we dissociate the effects of sleep from what we're doing that is causing us not to sleep so Jeff was getting very anxious about not writing this paper whatever the experimenters were doing to keep the mice sleep-deprived there's that interaction of whatever that is must be a stressor as well yeah I think that's such a very good point which is how do you disambiguate the detriment of continued wakefulness from the absence of sleep now that sounds sort of a bit confusing and tautological but it's actually not it's exactly what you're saying which is are the deficits that you see by way of a lack of sleep are they the deficits due to being awake longer or are they the deficits due to the absence of sleep and the way that we try to approach that is by then turning the tables and giving sleep back measuring the physiological quality of sleep and then saying is there something about the quality of sleep that is predicting the benefit that you get and then we can say is the benefit that you're getting which is predicted by your sleep quality the same thing that it becomes impaired or is detrimental II impacted by the absence of sleep whilst you're awake so we try to bootstrap that question by saying yes it could be just because you're awake but if something in your sleep is also been officially enhancing that thing and that same thing is detrimental e impaired when you take sleep away it's more than likely sleep dependent rather than wake or prolonged wake dependent so you it it's sometimes a bit hard to get the scalpel in between those two but there's ways of doing it in the animal studies it's much easier because you could do things like you can adrenalectomy is the animals you can take away the complete stress axis you can supplement them with cortisol so they stay alive and therefore any of the deficits that you say there can't be accounted for by just things like stress or you know the biology that comes with insufficient sleep and stress so you can sort of try to pattern match all of these things together and finally when you bring them together that gives you a holistic view of whether or not something truly is sleep dependent ok great talk ironically I think it was a real wake-up call what I want to ask you about and you sort of left it open and your talk was about sleep medication what effects that have you can say something general about that so we you know I learned about that in my undergrad a long time ago you know quality of sleep is maybe not as good but I also wonder if you could comment on the evolution of sleep medication you know if you know anything about how they've gotten better a lot of things in the market now that are not as bad as the ones they used to have or if the whole thing is terrible yes so the the drugs that we have right now for sleep they are called the sedative hypnotics there was the older versions and now there's the newer versions the newer versions should probably know about things like ambien lunesta sonata etc and they all however target the same receptor in the brain which is called the gaba receptor which and so all of those drugs are still sedating drugs and people mistake the former for sleep the latter and those two things aren't the same so firstly the the initial point is when you take those drugs you are not getting naturalistic sleep unfortunately if I were to show you your electrical signature when you are on those drugs or it's not the same the the second issue with those drugs is that as I said they've been associated with a significantly higher risk of death part of that seems to be due to a description of the immune system people seem to suffer far higher rates of infection when they're using those drugs the third aspect is that they seem to be strongly related to cancer now we don't have the causal studies in terms of their carcinogenic impact in fact the FDA has currently suggested that it may be difficult to do those studies because the weight of evidence the strength of the Association may actually make it ethically not viable to do those those studies that's how powerful it is and those drugs are being taken in large amounts in the last month 10 million Americans alone have swallowed some kind of sleep aid to put also the context around this it took George Lucas about 40 years to amass four billion in profit in the Star Wars franchise and it took ambien 24 months to accomplish that hi thank you so much again for your talk it was really insightful as a fellow student I feel that we weren't exactly surprised by what we learned here today because we experienced it every day we it's very rare that any student that I know gets over seven hours of sleep and I have a college student imagine what high school students are going through right now but I guess the main question that I have is what can we do to convince schools that sleep actually matters and that students aren't being lazy because you mentioned the 7:15 the 7:25 time I suspect the reason for that is because the schools usually use one fleet of buses yeah and that's just cheaper like how do you even argue with that so I think you know it is a non-trivial challenge to transport large numbers of individuals to a place such as a school at the same time and I'm not trying to trivialize that I think it's a really hard problem to solve but what I would say is that you know we've actually put people on the moon so I think it's also still a solvable challenge and I don't think you know having a bus Union and having some set schedule is a good enough excuse to compromise the brains and the development of the brains and the mental health and the physical health of our next generation because of that I truly don't now I think it's not easy just because of buses it's also because of parents needing to get to work at a certain time so it's actually a Herculean challenge it's actually much more complex than it would appear on the surface but again I have to imagine that there is there can be some solution that we can come up with delaying school start times new ways of transportation you know it's it's solvable and we should be able to get there and I think the data now is overwhelming oh I don't this shouldn't be a but I don't want that don't please don't don't by the well you don't need to read the book I don't know why that's a but um well actually you just need to buy it you don't need to read it that's the and if you can find an unsigned copy it's probably worth a fortune but so I think I truly believe that we will look back in twenty years time with some degree of shame on what we were doing with this early model of school start times and I think we will have those solutions then and by the way if you're worried about the financial cost of trying to increase the number of buses or even just do some kind of alternative transport the model pays for itself in at least two ways firstly the increase in grade performance in terms of the benefit for the economy and jobs is astronomical and the RAND Corporation an independent survey company has actually scaled this out and all of the data is there and it's very impressive secondly when kids go to school later they come out the other end later there is a period of time called the bewitching hour for crime which is when kids get out of school but before their parents get home and they are unbuckle from a parental advisory role that's where most juvenile crime typically spikes well we would add void we would have avoid that spike by later school start times and the savings by way of that alone for crime would pay for the extra bus services so you can't tell me that it's financially too expensive that just doesn't work as a response thank you you're welcome thank you for the excellent talk I have a question that's slightly cheeky but I also have a massive sleep deficit so you can put it down to mental illness I was wondering how many hours of sleep you get on average every night and how you balance your work because you're clearly quite very very very productive and you do a lot so how do you do it so don't rush to judgment on me the balata it's just because I have wonderful students and people at the sleep center I get I give myself a non-negotiable eight-hour opportunity every night and I say that not because I want to be some kind of poster child for the cause I am on a mission to some degree but that's not the reason I give myself that time if you knew the evidence as I do regarding disease and sickness that comes by way of insufficient sleep you would choose to do nothing other than that it's a purely selfish act on my behalf you know my family for example has a very strong history of cardiovascular disease and deep sleep is the very best blood pressure medication that you could ever wish for so I don't want to shorter life and I don't want a shorter life that is filled with disease I want a longer life but I also want a longer not just lifespan but health span and the very best health insurance policy that's largely Democratic mostly freely available and for the most part painless is this thing called an eight-hour night of sleep that's really great thank you hello I think I've got just one more question either side I'm so sorry and then I'll take others after thank you so much for your great talk so I'm an undergraduate student who actually sleeps and so I was wondering about deep sleep and the sleep spindles that you mentioned because I've been tracking my sleep for the past three months and I've noticed that my deep sleep percentage is like between 14 and 17 percent so I really want to know like what is you know REM and light sleep have to do with the whole memory consolidation and whether it's only deep sleep that the cardio is the one that has all the benefits yes so if you're sort of averaging around a sort of 14% you should definitely go to the hospital right away and I'll stop answering the question no I'm kidding you so firstly um what are you using to track your sleep what device yep so right now the accuracy of these devices and you know I'm wearing an orange the accuracy of these devices is just not there yet in terms of separating out your deep sleep from your light sleep from your REM sleep so I wouldn't try to get too concerned about that there's something called Auto Somme Nia which is a new disorder where people are getting sort of a bit hyper attentive to their sleep by way of trackers I know can you believe it although from the Greek origin meaning straightening that's why you'd probably think of Orthopaedic it's about straining bones and SAAM near being sleep so it's about getting your sleep perfect and straight and so I wouldn't worry about that too much what I would come back to is your question about which is the best type of sleep as it were to get what should I worry about and it took mother nature of 3.6 million years to put this collection and constellation of different sleep stages in place what we have discovered is that every single stage of sleep is important there isn't one that's more important than the other they serve complimentary but different for actions at different times of night but to suggest that any one of them may be more beneficial than the other is probably I mean if that was true I suspect mother nature would have excised the weakling of the sleep bunch long ago and the fact that they are still there tells you that you still need all of them I suspect so keep sleeping you're eight hours I know that you said ever since you turned sixty you've been sleeping eight hours and it's working out for you very well sir thank you I think I've just got one more question maybe sorry historic literature's human sleep scene to shift before the invention of the night light source yeah sleep sleeping behavior may influence the quality of our sleep yes so there's some of you may have heard of this thing called first sleep and second sleep where people would sort of have about three or four hours at the first often they would wake up they would socialize music food people make love three-hour gap and then they would go back to bed again for another sort of three or four hours certainly it was a practice that happened it was during the Kenzi n' era and is that how we were designed to sleep no it doesn't seem to be that way if you look at your biology there's nothing suggesting that that's how we should sleep however should we be sleeping the way we do sleep in modernity which is what we call mono physically and the answer seems to be maybe not either because if you study hunter-gatherer tribes and we've sort of looked at some of this work to where their way of life has not changed for thousands of years they don't sleep the way that we do they sleep by physically where they have about six and a half hours at night and then about an hour in the afternoon us yes the like behavior and in fact you're all programmed to do this it's that afternoon lull where you get the sort of the head bobs like it's got nothing to do with lunch by the way I can take away your lunch and you still have this pre-programmed drop in your alertness it's sort of it's not people listening to good music it's just you're falling prey to what's called the postprandial dip it's genetically inforced it's hardwired everyone seems to have it the argument is that we should be sleeping by physically so how we are sleeping in terms of our the bouts seems to have changed with modernity but also the timing if you look at those hunter-gatherer tribes for their nighttime period of sleep they are not sleeping when we are sleeping have you ever wondered what the term midnight actually means middle of the night now midnight in first world nations has now become typically the last time that we check Facebook and we think about the emails or you know but for those individuals that's actually the middle of their sleep cycle that's the middle of the the solar cycle and their sleep cycle as well so modernity is distorted how we sleep both in terms of bouts the amount of sleep that we're getting and the timing of our sleep on the 24-hour clock face I think I should stop thank you so much again thank you

Channel: Cognitive Neuroscience Society

Views: 81,982

Rating: 4.9286323 out of 5

Keywords: sleep, science, neuroscience, memory, Matthew Walker, cns 2019, brain, health

Id: vCEjNNCFR5c

Length: 64min 22sec (3862 seconds)

Published: Fri Apr 05 2019

Reddit Comments

[u/RedditUsr2]

Presented by Matthew Walker at the Cognitive Neuroscience Society.

Matt Walker founded the Center for Human Sleep Science.