Bucket of making sense podcast, this is SAM Harris just a note to say that if your hearing this, you are not currently honour, subscriber feed and only be hearing the first part of this conversation in order to access full episodes of the making sense, podcast you'll need to subscribe. Sam Aristotle work Org. There you'll find a private rss feed to add to your favorite podcast sure, along with other subscriber only content, we don't run ads on the podcast and therefore it's made possible entirely to the support of our subscribers. So, if enjoy what we're doing here, please consider becoming one today speaking with Matthew, Walker mad as a profession. Neuroscience and psychology you see Berkeley and the director of it Leap and narrow imaging lab and is also a former professors

country at Harvard University. He has passed rushed over one hundred scientific studies and has appeared on sixty minutes Nova BBC News and many other outlets, his first book, why we sleep in an international best seller, and he also his own podcast, the mat Walker Podcast. I've been wanting speak to mad for quite some time because you're here have been increasingly worried about the quality of my own sleep. later. The party here Now I am convinced of the importance of sleeping well, most nights and men, and I get into all the details here about the nature and importance of sleep. We discuss slow Ben Consciousness, the stages asleep, sleep, regularity, light and temperature, the evolutionary origins of sleep in Egypt, early doomed attempt to reduce ones need for sleep, the connection

between deficiencies and sleep and or cause mortality, Alzheimer's Disease diabetes, obesity and heart disease, the role we played and learning and memory and mental health heart read, variability billowy ram sleep, you're disorder and various. some news Gus, lucid dreaming dreams at a kind of therapy, the connection When meditation and sleep the various forms of insomnia and there are practical tips from to do about them strewn through our conversation. We discussed leap? Hygiene caffeine alcohol, sleep efficiency time restriction napping and finally, sleep tracking and who here on that final topic of sleep, tracking madness discover that each of us is associated with the company aura. That makes a sleep tracking ring.

I am a minor investor in the company and mad is its scientific adviser. Neither of us now but the connection before we started talking and you're. Here I have a bit of a of hate relationship with my own or a ring. It is workable device, but I may have what mad calls or thoughts Omnia. which is an over abundance of concern about my sleep data case. Make of that. You will help me find conversation, useful It runs nearly four hours now bring you Matthew. I am here with Matthew Walker. Man thanks we're going to me. It's a delight in a privilege to be speaking with you, SAM thanks for having me save written a book. Why we sleep that tat seems to have gotten into the hands, if not the the brains of of more as everyone

and now you have a your own podcast, the Mat Walker Podcast and you have been on many, many podcast said that I've noticed talking about the science of sleep and seemingly almost single handedly making people newly aware of the importance of sleep lives both. For me, the side of in a physical health and mental health. Emotional regulation really just across the board when you're talking about human well being the difference between good and bad sleep seems pair MT and I must say I have really Nick collected, so as a variable for most of my life. In fact, I think I was early in life toyed with the fairly crazy ideal of limiting sweep so as to boost productivity.

And we'll get it all of that, but you before we dive into the specific chapters of our conversation here. Perhaps you can introduce yourself you your at ground, intellectually and and academically an unjust, tell us how you came to focus on sweep. I wish I could take the compliment of bringing sleep back on to the public awareness map. I stand on the shoulders of many of my colleagues and they are astronaut Mclean wonderful. So I tried to do my part in terms of my background. I am a professor of neuroscience and psychology at the University of California, Buckley in America and I've Riddy try to dedicate myself to understanding the question of why we sleep. For the past twenty years, I think. Like most people, I am an accidental sleet research up. I often think in her when kids are

young and the teacher says, tell me what he would like to be when you grow up no ones. shooting by hand up in the classroom and say I desperately want to be asleep research it yeah and I can attest there tat when I started my neuroscience phd, someone from asleep lab. I forget who tried to recruit me to their land? and I I thought Why would I want to study sleep had no interest at that point and em Now I feel some chagrin over that their dismissal, because it is increasingly fascinating I said consequential and in some ways I you know, I don't blame you- may be at the time sent me even twenty Is it go? One could argue: it's almost academic suicide to suggest that you want to become a sleet researcher and and not necessarily truthful, but some would argue that it was almost a charlatan science to begin with, and of course it is it's bad, the most bizarre strange

illogical, irrational from an evolutionary perspective, idiotic thing, that an organism can do and you're going to leverage entire academic career on that platform, good luck and good night would be there. I think the tagline, But- I was studying for my phd people with different forms of dementia and I was using brainwave patents to try and differentially died- knows them very early on in the course of of dementia, and I was failing miserably, couldn't get any good results and one weekend. I had this little igloo of journals that I would retreat to, which tells you everything about my social life and I started to learn that some of those dementias would eat away at sleep centres and other forms of feed. Dementias would not, because there are many different forms of dementia realized I was measuring. Might patients at the wrong time, which was when they were awake and I should be met

them when they were asleep. I started doing that. I got some fantastic results and at that point I started to ask the question. I wonder if these sleep disruptions and improvements are not a consequence of the dimensions not a symptom of the dependent dimension. Maybe they are a cause of feet dimension, but I realized twenty years ago. No one could answer very fundamental question, which was: why do we sleep? And I think the crass answer, that time was that we sleep to cure sleepiness, which his tea, the fact she was equivalent of saying I eat to cure hunger. Tells you nothing about the unique benefits, but then I started to explore this thing called sleep and I fell absolutely in love that and to this day twenty is on. I still think it is the most beguiling thing in science is a love affair. That's not left me for all of those decades.

and I remain an amorous partner to its wonderful gifts, both nightly as a practice and also from her intellectual and academic, and Such perspective does not give some background. Yeah yeah. I can follow your romantic analogy here, sir. it is a fairly coyness press for many of us and this speaking personally. This has always been not even on the back burner. For me as a problem to solve in my life. I just I've accustomed myself to see being badly and justice acting on some level, that I I sleep badly and so encounter in your work fairly arrest in to someone, in my condition, because either stakes as we will lose right here are are incredibly high. Given the canoe, in between sleep and health, so

at the outset address the component of worry Here worry about sleep many people listening to us all I recognise that in themselves, at their their sleep is far from ideal and and to add a layer of worry too, that is obvious. counterproductive when, when the goal is to make it easier to sleep soundly and on some, your schedule in general. So can you addressed this this effect there? Our conversation is likely to have a special when we're talking about possible links between poor sleep and dementia and all the rest is just very easy to begin to treat. This is some kind of medical emergency in the offing. What what do you have to by way of guidance caution on that point. In some way,

it's a rock and a hard place that I found myself in, and this is think that I've learned since publishing the book- and I think it's something that I've corrected in my communication to the public as I was, writing the book at the time, at least within the public sphere. As you mentioned, sleep was the neglected step system in the health conversation of today when it was that way, and

I was so familiar as all of my colleagues were with the disease and the sickness and the suffering that was happening, because if this sleep deficiency that was so pernicious throughout most first world nations that I wanted to try to hear no pun intended for either this podcast all the topic but set of white people up to the fact of the importance of sleep, and I think that in my communications and maybe even in segments of the book, I was perhaps heavy handed and I had neglected to recognise the concern for the sleep, anxious and those who are

things. Sleep difficulty and I have since become so much more sensitive to that, and I can't deny the science. I can't not tell you about the links between insufficient sleep and Alzheimer's disease, obesity, diabetes, he's cardiovascular disease, depression, anxiety and suicide, some forms of cancer, but I also don't want people to become overly anxious. But how do you do that? How'd? You find that sweet spot. So for me it's been a real lesson and a lesson also because I am no poster child for sleep. I have had my battles and I did not mention them in the book, and I think I should have been personally open a memory private person.

I've had at least three bouts of insomnia during my lifetime and they were vicious, and just because you know little about sleep doesn't mean as though you are immune to its vagaries. It is a a mistress that can be re fickle. So I think for this podcast, it's important to keep in mind two things. First, everyone has a bad nice of sleep and, if you're there at night struggling to fall, asleep dont worry, even with all the facts and the science that we will discuss. It's not the worst thing in the world. The second thing is that if you are persistently,

and continuously chronically struggling to sleep you dont have to because there are efficacious treatments, many of them non pharmacological, which is great. That can help course correct. In fact, even in older adults, where you think there is no hope at all for solid night of sleep, those therapies, many of them seemed to be beneficial to restoring some degree of good sleep, so you don't have to suffer in the time silence, but there is benefit them. I think that that perhaps the best way to approach it with sensitivity, compassion, understanding but true follow up to the signs in I I want to make people nervous about. You know it so precisely that it doesn't change that blood sugar set them on a path towards pre, diabetes or type two diabetes.

And what you've become so obsessive and anxious that food and the joint pleasures of eating start to fail. I also don't want to do that with sleep, but I equally don't want to tell you It's fine just to eat a plate of of ice cream every night and that your blood sugar would suffer I'll. Tell you about that. Cites to ya He also that that's great by way of introduction- and we will get into all of the aspects here, including all the practical recommendations. You have him sleep and bypassed in any perverse called a sack of worry about sleep that can get in the way of that project. So let's just begin less choice. Ben to our first after here on what sleep is even before answering the question is: is the title of your book

about why we sleep what is sweep from a functional perspective? I think the headline state, when you could argue is that sleep physiologically at least is perhaps the single most effective thing that we can do every day to reset the health of our brain and all buddy and that's not to dismiss food or nutrition exercise. But if you were to take Butte some Harrison, I would deprive you of food for twenty four hours deprive you of water, for twenty four hours, deprive you of physical activity for twenty four hours or deprive you of sleep for twenty four hours, and I were to look across your brain on your body and see which one demonstrate the more demonstrable impairment by a very large margin. It's it's sleep I dont want is that of do that Coat Pepsi, doktor pepper, I'm still missing one accounting of it challenge see. You could ask from a functional perspective what sleepers

could also ask what is sleep as a process that unfolds across the night in terms of its architecture and the can also ask and debate what is sleep as a conscious state versus a non conscious state? And so I am happy to maybe speak about how sleep unfold. Since that may be the logic entry point or just go straight into how we can noodle and wrestle with the idea of it being a conscious versus unconscious state which can get us into total logical waters, but You tell me which of those two perhaps would be best to start with a fruitful, for you will be the question of whether a conscious is some. And I have spoken about this elsewhere is very difficult resolve, just because it's difficult discriminate and into corruption in consciousness from a mere failure of memory which offer his dreams are routine,

conscious, but is also possible to have dreams and and not recall them at all, and then One could wonder whether those dreams we know whether those stages of ran sleep well actually associated with conscious dreaming One could wonder that the state of deep sleep is also a state of conscious his enjoyment of something quieter form, listen profound, but there's just no memory of it, and so we we read, it has just a lot of experience. for that parents and how we would read me, I'm happy to hear anything you you think on a topic, but I am unaware of anything that would resolve that. For us. I think it's a very elegant point, which is we rely for that question, import subjectively from the sleeper themselves, a report of whether or not they were expelled,

seeing anything going through their mind just before we woke them up and said: what will you having as an experience and that suffers from, but the failures of memory, which we know happen just because you don't remember your dreams. Doesn't mean that you weren't dreaming. I think one way that you can get closer, but we will still fail, is too late that question a part on the basis of perception Which is to say pending on your desk we behaviorally the way that we define sleep in other species where we can't, for example, stick electrodes on them is, as condition in which The organism stops responding to the outside world, which is about perception. Does this mean. we are not conscious during sleep, because we typically stop responding to the outside world in all stages of sleep And that depends on your definition of consciousness, but we stop interact,

dealing with and for the most part perceiving the outside world. Which some would argue is a loss of consciousness or at least a shift towards non consciousness. But I'd counter argue that we don't entirely stop perceiving the outside world. To, for example, I can have electrodes on your. add my complete sounds while your sleep that don't wake you up and I can still see The brain at some level is processing. Those sounds in a way that is, not dissimilar to the way it does when were awake. Consciously perceiving, though sounds, we can do F, MRI studies and we can play those sounds as you're sleeping in the MRI Scanner hard to believe that people can, but they do sleep in the scanner, and can see that there are different ways of perception is a great pity that looked at new mothers and what they found was that when they played the cry of the infant first

another sound, even though they remained sleep. It was a very different network, salience network activated in response to the child of that mother verses. Another sound of equal value, Mc Cetera, so there is definitely some degree of processing and discriminate processing, but I still don't think it's the same known, conscious state as Annesley. Meaning that there is still some degree of perception of the outside world during deep sleep, in other words, what we call extra reception, the ability to focus or since the outset, well, what will there's gotta be just based on the fact that you can wait somebody up from the asleep That's gotta get in somehow that's exactly it. Yeah I've seen you you exactly predicted, Whether conversation was going, which is that no matter what stage your in sleep,

but this is a condition in which it is environmentally reversible. For example, if sound is loud in a fourth somewhat to pinch, your skin hard enough european. Secretly cruel. Thank goodness to do when they went to sleep. You would wake up from sleep, which is to say that in sleep we are unresponsive, but that state of unresponsive anti Israel. Possible. Now, that's not true of anesthesia or death for as best we can tell I think it's very hard to argue, then that we don't have a very substantive, yet qualitatively different form of consciousness when we dream, especially during where we go into REM, sleep dreaming. So I think we can get a little bit closer to a dissection of what do we think of as the state of course this processing during sleep, but I still feel as though I dont see data that can really solidly give us one argument in in either favour conscious and unconscious,

here. I would just add here that, conversely, there are states of meditation were drug and toxic nation, where someone is, is also tone unresponsive to the outside world, but also conscious of something really mean terms of their subjective report once they come back from those experiences, so others a double dissociation here. So I think, responsiveness stimuli. Isn't it we need we need- we obviously need the neural or a lot of consciousness where we can do a scan, your brain and say you know best methodology and say: okay. This is the footprint of consciousness. Human brain and it winks out in this condition, let's say general anesthesia and its He waited to this degree in this stage of sleep, but unfortunately We don't have that yet, and I think there are conceptual and operational limits to our getting

again. There were the role of self report is always eventually confounding Anne and seditious here, because you can just scenario we just need a sufficient cohort of people who are poured in things occurred in the chair after that, we're deeming to be unconscious and You know he either we're going to think they're delusional or their line or therein some other way wrong or we're going to, or that's going to erode our confidence that really the lights are out during that epoch? Having self report speaking about fickle mistresses? Yes, Europe is so prone all of those areas? Ok, so that caviar in mind less launching too? It would be good to just give us structure of sleep here in human beings examining else you want about other animals but term what?

what is sleep for people asleep, at least in human beings and in fact, in all mammalian, he sees as long as they are land dwellings caviar. That, too, is broadly separated into two main types. On the one hand we have non rapid eye movement, sleep or non ram sleep for short On the other hand, we have rapid movement, sleep or orient sleep aft and want to make people clear on the fact that that's named, not after the popular nineteen nineteen million stipe pop banned, but because of is bizarre, horizontal shuttling movements that occurred during this stage of sleep. That's where it gets its definitional name from and can back to non ram sleep, which I always feel sorry for by the way. Isn't it isn't it sad to be dead find by some think that you're not nah, not rem, sleep. I guess

we're going as in this case, your deep and light. That's correct. So on rent sleep is then further subdivided into for supper stages increasing in the depth of sleep, so stages wanting to or what we would consider or your sleep tracker will probably try to tell you are the light stages of non room sleep, whereas stages, three and four? That's the ready, deep non ram, sleep and rem. Sleep, then, is the stage at which we principally dream, depending on your definition, dreaming, isn't excuse save to ram sleeping, but for what most people would say in the public, this is dreaming what they really referring to the bizarre narrative, hallucinogenic motion. All memory laden experiences that come from this thing called REM Sleep, so those two types

sleep, non ram and ram will play out effectively in a battle for rain domination throughout the night and that the war between Non RAM and rem in humans, at least and is different for different species, will last about ninety minutes, and that creates for the average adult approach a typical ninety minute cycle, will you go into Non rem, sleep and then, go into rem sleep. But what changes, however, is the ratio of non rent ram within those ninety minute cycles, as you move across the night, so in other words, in the first half of the night, the majority of those mighty minute cycles are going to be comprised of lots of non ram sleep, particularly deep nano sleep, but, as you push through to the second half of the night, that sort of sea

so balance shifts over and those ninety minute cycles are comprised of much more rapid movement, sleep and very little deep sleep I met her some consequences that we can also talk about, but I would probably mention also. Every one of those stages of sleep or almost all, of those stages of sleep. We have now learned our important. There is no. One more important stage of sleep than the other. Now you can argue well what are you talking about importance? You talking about mortality, risk and death, and we can use that as a filter debate that is well, but overall, different stages of sleep provide different functions for the brain and the body at different times of night, so we need all of those stages, and is it true that tat we generally wake up, however, briefly in industry, nobly after

each of these ninety minute phases, you you get through you're here period and then there's a brief awakening. That's that's absolutely I'm! Yet you definitely need to be asleep research. It take us ethical and tell me a time machine and uncle back a conversation differently so we we do know that usually at the end the end of every one of those? Ninety minutes the cycles at the end of each of those rem phases? There is a brief elimination of sleep where we wake up and in part, we think that that's perhaps because of the need to manoeuvre, the body and change the bodies position. So we have these brief awakenings. They usually so brief that most of us, don't recall them they're, not imprint, it in memory, but everyone will typically have a brief awakening and then a movement episode after where they shift position right and I'm talk about sleep tracking.

and the tools that are available to do that personally, beyond going two asleep lab and getting totally hooked up by term viewing these stages in there totality meet. You ve said that each is dispensable buddy does seem, at least in me. The way one communicates the the imperative to get all of these stages. Most of us are not deficient in the stages of light sleep, ass, really the stages of ram and deep sleep there are marketed as truly restorative right and that those are that the areas of real deficiency Mesa, for instance. If what was sleeping It's ours, but they got very long, epochs of deep sleep and ran sleep would that strike you as a much healthier profile than some one sleeping six hours, but is most we devoted to the stages

and two of light sleep. Yes, I think that that is fair to say. We do need stage too, as well. We ve discovered that stage to non room. Sleep is associated with certain forms of memory and memory processing and there is a particular electric oh feature of stage to normal sleep, which continues on into deep noncom sleep stages. Three and four called sleep swindles, which these men, who you two full little champagne corks synchronous, bursts of electrical activity that happen during stage to non ram sleep and then say just three and four they last for about a second in a second and a half, and they seem to be critical for a number of different processes of both the brain and they seem to transact will be at least associated with several benefits for the body. But overall, I would say

It is very difficult to have a night where you're not transitioning, because when you go down into deep non ram sleep, you have to progress through stage too, and when you're coming out of deep non ram sleep, you have two progressed through stage to Non M sleep again, the light, a form of non GM sleep before you get up interim sleep, and so it would probably be wrong. the difficulty you can manipulate conditions in which this can happen, which I will be with, but what you could have the same. that you described but for the most part, you're still going to get that stage to non arab sleep. Yet what you said is correct this is where it bail them. I'll see you with their practical questions throughout, but damn the first comes to mind here- is what are the implications of. Waking with an alarm clock, verses, waking.

Were they and the change and enlightened conditions born of sunlight coming through the window? I guess I see the implication. of using asleep mask or Asia or black out curtains, where you're not getting Environmental white queues I can imagine you know you're unlucky, your alarmed rings when you're in in state for sleep say and your brought out of that. Less than ideal way waterway at what? What are those, what are those effects and in what are you actually recommend if persons schedule allows for it? What Would you recommend, as it has a motive of waking up in the morning, unless You are waking up within the first couple of hours of sleep, unlikely that your alarm would wake you up in the deep stages of non ram? Sleep! That's not true. However, if you take an afternoon nap and that nap less a little bit too long near and by tools.

What I mean is you're going past, that sort of twenty to twenty five minutes and you're starting to go down into the deep sleep, and then your alarm wakes you up, then you almost have this sleep I over for the net our also has Napster level gonna its with a change of times on when you, when you have terrible jet lag and decide. can in no way I'm gonna make it to the EU inside, I gotta give myself an hour or two sleep here, and that that day they were waken up in that hours, just about the worst wake up, whenever guess its prey, the grim. Isn't it and it's what we call sleep inertia where you get a state carry over where your brain, never typically wakes up from, is jolted out of that deep sleep naturalistic early from an evolutionary perspective across. Millions of years- that's not being the case and so not well prepared for recovery

from that assault. And would we suffer this terrible sleep, sleep inertia, so it's not so likely to happen, but when it does happen its grim, it can also but at night when, for example, you get a phone call and over signet wake you up at the end of two thirty thirty in the morning and one again, your jolted out from that deep sleep and yes, you can answer the phone and you can be somewhat responsive, but it is just grim you're in this too, trickle haze of cognitive dysfunction and it's all you can do to allow words to Tom while in some meaningful way one foot in front of the other out of your mouth, so that is perhaps less likely circumstance. What would I suggest it's difficult because one of the critical things that people need to do to get their sleep back on track is the simple act of regularity. There's going to be

and waking up sing time, no matter whether it's the week day or the weekend, and for that we often require an alarm clock and I also add, Kate for people not just to have an alarm clock in the morning. But why don't we have set alarm as well as eight to wake alarm and it's one way to help keep us on schedule and track. I would say, however, that if you study Hunter Gatherer tribes, whose way of life has already changed, for you know hundreds if not thousands of years, they don't seem to wake up in an artificial matter, and if you ask them, you know, do you find ways to force yourself to wake up. They find it a perplexing question: why would you buy? would you tell me something: that's not yet complete. It's a little bit like saying. Why would you go out to your favorite restaurant or do your favorite dish have two bites of that dish and then get up and walk?

I thought you would stay until your foot. when you are complete without meal, and why would we wake up when we are not yet full of the fleet that we need a mother nature will take care of that when it's time to wake up, and we ve had the sleep that we need We do so one way some people will ask me: how do I know if I'm getting enough sleep? It's not the ideal way, but one suggestion is to say if you alarm clock didn't go off in the morning. Would you sleep past that alone? And if the answer is yes, then you're still carrying some degree of asleep need, which means that by waking up artificially your inducing asleep debt as a consequence. What about them? role of light queues in bringing some one out of sweet its, we to think that light perhaps was the trigger off or one of the facilitating. actions for rising people out from sleep in the morning and again

Looking at those hunt together, tribes, what we found is that that's not really the case. They often typically will wake up a little bit before the dawn. What seems to be the trigger for The arrival of wakefulness and the termination of sleep is more so temperature both that internal temperature, the ambient temperature rising, because often they will sleep with the environment, with ambient temperature, unlike many of us in modernity, while we have a controlled temperature em. So that's not to suggest that, like be a facilitator to help you wake up in the morning, and in fact I will. I have one. these little smart lights. Next to my bedside and I programme it to try and say you know two minutes before the time that you're supposed to wake up start to bring light into the room. I would say, though, that

I do have an alarm myself. My alarm is, and we get into sort of prototypes and what your preferences, but my alarm is set for around seven o four in the morning or at seven hundred four in the morning, not because this area special or unique. Please don't go rushing out and changing your way. Time to that we're not gonna, have to have a chapter on new morality here and in the evening and unreasoning do? That is why not just be idiosyncratic? Why would you set it at the seventy, five or seven or seven ten with just why not seven of it tells you probably everything about me and why I'm desperately unpopular put sue button I use they wake up. Naturally, I would say about eighty percent of the time I wake up, naturally before my alarm clock. So I think, through one of the worries that people have when I tell him to do the experts and if you have the luxury in the shadow of flexibility, to do it and stop your alarm and

sleep in the way that you are your body, wants to sleep. The greatest worry is that my goodness I normally wake up at seven and I'll. Probably wake up at nine o clock in the morning is the first concern now. That may be true to begin with, for the first few days, because you're probably trying to sleep back a debt that you ve asked chronically of weeks, if not months or years, and this second problem is that when people sleep long, they wake up. Once again we have that strangely Peng over effect were if they get nine hours of sleep they feel worse than when they can seven hours of sleep. That is typically because you are in the phase of paying back the debt and, if you Let that experiment play out for another week. You wash away that pressure to sleep. Now we can see, about sleep data with whether you can ever truly pay back the bank or not, but

that goes away with time it sort of like detoxified from a drug at first. Its brutal of all of these side effects. And you have a withdrawal syndrome and in some ways that's the withdrawal syndrome, where you start sleeping longer that settles down it's like erect a shop and then it finds a sweets and gradually you will actually acquiesce to your typical sleep need in your sleep profile. Most people don't have the luxury to do that, so light can be helpful. Temperature is one I also have one of those smart home, thermostats and temperature is critical for sleep. We need to ironically warm up to cool down to fall asleep and then we need to. Cool to stay asleep, Finally, we need to warm up to wake up, and so you can create a bit tailored temperature profile for your night of sleep

can help to some degree now, of course, you're under the sheets and the ambient has role to play, but it also halted by what's going on locally, underneath the sheets to see you can't control exquisitely, that's were smart mattresses coming in to train wreck. Take that out the equation so there are some of the ways that you can play around with sleep. I do like the idea. If you are particularly If you are a night owl an you struggle to wake up the time that society forces you to which is not in synchrony with your morning, this off evening, this preference you can use, light in the morning, but then you can reverse that can the evening when you try to ensconced yourself with as much dim light and darkness to help you try to get to bed a little bit earlier. So it's not as though light should be dismissed and.

blocking devices blackout curtains, I masks a plugs. Sound is another pollution that will disrupt your sleep I will typically used use all of those who, like guns I haven't. I must and then I have earplugs I'm, I think hope I'm starting to sound like the Woody Allen Neurotic of this world, but that's just may ass. Well, when he is one picture of this set up into completely discredit. Usa expert on sleep like when you say, discredited by lots of different things, but that would, I think, seal the deal ok, so was transition to the quest, of. Why we sleep, I think, was probably no real boundary between what sleep is in and why we do it concerns Surely here, at least in places, because some part The story here is the the evolutionary question of just why sleep is a thing how it came to be that animals like ourselves, Derek

so much of their lives to this state. That seems fairly p, it will send even dangerous, menaces thee, you can imagine in Seville in the the danger is less salient, but it just imagine how precarious it would be to go on in the woods where there are bears, and perhaps several other. Species that good Are you a meal and to just take heed hours of darkness to be unconscious. For- and this is a pity, and Shaw evolutionary answer there in nets. The one thing you're not doing well, you're sleeping is stumbling around in the dark, where you're not very good at seeing and several things can see you better than you can see them, but I am not sure that inadequate a rationale. So, let's in talking about the origins of sleep, his son, we,

no them or condemn hypotheses about them. Why? What? What do you think about turn? Why sleep even exists so far in every species that we ve studied to date. Sleep was I think that looks very much like it seems to exist and what that is justice. Is that sleep evolved with life? itself on this planet and has fought its way through heroically every step along the evolutionary pathway, thus linger on that point. That is very interesting, as you can imagine, imagined the adaptive benefits it would generally accrue to any species that could just get. Over its need for sleep and that there would have been you would think of a selective pressure in the direction of Plainly? Erasing sleep, so it's suggests it's rather hard to do. I think it's a beautiful way of thinking about it because from an evolutionary perspective, just as you know,

It is the most idiotic of all things. Firstly, when your sleep, you're, not eating, cannot foraging for food you're, not finding a mate, you not reproducing you not caring your young and, worst of all, as you noted your vulnerable to predation, so on any one of those grounds, but especially both of them as it as a collective sleep should have been strongly selected against during the course of evolution and its once being said that if sleep doesnt serve absolutely vital, action? Then it's the biggest mistake, the evolutionary process ever made and what we ve now since learned, is that mother Nature didn't make a spectacular blundering, creating this thing called sleep, but even very old. Evolutionary video species, like earthworms, for example, seem to have periods of schools of thought, because so essentially asleep like stays in a

sleep back millions of years, even some bacteria that seem to live at least several days. They will have an active phase in a passive face, perhaps the precursor to sleep, so you're right, you could well imagine why, if some species had understood away to circumnavigate its way around the essential need for sleep. It would have dominated full lots of different reasons, at least within its species category. The fact that we haven't seen that get argues that sleet must be fundamental at the most basic of biological levels, and it's one of the reasons why, when people will say to me up Can't you enough Europe, a doctor training. I think we learned to overcome our need for sleep we learned to to tolerate it. And deal with insufficient sleep, and you can do that if you could

Just me I think more than it you know the same degree of of hubris thou which his mother nature. If she could have even half the amount of time You are vulnerable to all of those are vicissitudes of sleep she sent me would have and the fact that its being preserved you that doesn't seem to be possible within the lifespan. We think that come along and within a ten year training of Korea. We could overcome it. It's it's unlikely to be the case, How should I think, is the right way punctuate this part of the common, nation, with the cases of fur very people who these by their own testimony, have gone fair way towards overcoming their personal need for sleep, and I think it was Winston Churchill who, during the warriors, was sleeping the latter ten minutes of every hour or something like that. I don't know if that's ok, wherefore, but what do we know about?

any ones successfully I trading there there sweep down to something like a minimum and I'm sure there's their GINO types here that we may know something about where people just require less sleep, then then his normal? are actually went once had a doctor who claimed No more than three. Have ours a night and Do you know whether he was again this it before the end of the age of three tracking, so he could have been delusional but do. We know about people who sweep much less than you would recommend fussy from an epidemiological a population based perspective which is simply association using that sweets. That we recommend, which is somewhere between seven to nine hours a night for the average adult once you start to get less than that, the short your sleep, the shorter your life that shortly predicts or cause mortality

People in history you ve, claimed to be short sleepers thereof, and Churchill was one Edison. Was another. Although Edison was a habitual nap during the day and he used naps and sleep as a creative tool, then you have Thatcher Margaret Thatcher where you have Ronald Reagan, just name but people who ended there. Their lives Sir, with Alzheimer's. So that's not a wreck marshals everywhere around owing yeah, but you know they seemed if or on the face of it to make it through. Until the you know, fifty years or even sixties, my goodness. Third, there is evidence of proof you can sleep what they claimed to be sleeping with just four hours a night and get away with it and ultimately, what we learned is that

one way or another, sleep deficiency seems to get its hucks into you, that the elastic band of sleep deprivation can stretch only so far before it snaps and tragically, for both of those individuals, Thatcher and Reagan. They came to the disease of of of Alzheimer's, and we now know now realize we have several files open, but term. Each of these is seems him. Word, and so on that point, how do we disentangle associate? asian and causation here, because it could also be true that one of these early symptoms of Alzheimer's, being at a special risk, for it is to have one's an ability to sleep diminish over the of one's life even may be starting as early as once thirty's or forties. Yes, a weakened Alzheimer's disease is actually a great example. It's probably being. I think that one of the most exciting areas of sleep research in terms of discovery

in the past ten or even five years, we started with just those epidemiological associations which are simply no correlation and organisation. If you'd like to continue assigned to this conversation, you'll need to subscribe SAM Herriston work once you do, you'll get access to all full length, episode of making sense podcast, along with other subscriber only content, including bonus episodes in a maze and the conversations I've been having on the waking up at the makings, has podcast his ad free and relies entirely on listener support, and you can subscribe now at Samara, steady work.