The Science & Practice of Perfecting Your Sleep | Dr. Matt Walker

1. 0:00 – 2:00

   Introducing Dr. Matt Walker

   1. AHAndrew Huberman0:00

      (music) Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, I have the pleasure of introducing Dr. Matthew Walker as our guest on the Huberman Lab Podcast. Dr. Walker is a professor of neuroscience and psychology at the University of California, Berkeley. There, his laboratory studies sleep. They study why we sleep, what occurs during sleep, such as dreams and why we dream, learning during sleep, as well as the consequences of getting insufficient or poor quality sleep on waking states. Dr. Walker is also the author of the international best-selling book, Why We Sleep. Our discussion today is an absolutely fascinating one for anyone that's interested in sleep, learning, or human performance of any kind. Dr. Walker teaches us how to get better at sleeping. He also discusses naps, whether or not we should or should not nap, whether or not we can compensate for lost sleep, and if so, how to best do that. We discuss behavioral protocols and interactions with light, temperature, supplementation, food, exercise, sex, all the variables that can impact this incredible state of mind and body that we call sleep. During my scientific career, I've read many papers about sleep and attended many seminars about sleep. Yet, my discussion with Dr. Walker today revealed to me more about sleep, sleep science, and how to get better at sleeping than all of those papers and seminars combined. I'm also delighted to share that Dr. Walker has started a podcast. That podcast, entitled The Matt Walker Podcast, releases its first episode this month and is going to teach all about sleep and how to get better at sleeping. So be sure to check out The Matt Walker Podcast on Apple, Spotify, or wherever you listen to podcasts. Before

2. 2:00 – 6:00

   Sponsors: Roka, InsideTracker

   1. AHAndrew Huberman2:00

      we begin, I'd like to mention that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero cost to consumer information about science and science-related tools to the general public. In keeping with that theme, I'd like to thank the sponsors of today's podcast. Our first sponsor is ROKA. ROKA makes sunglasses and eyeglasses that are of the absolutely highest quality. The company was founded by two all-American swimmers from Stanford, and everything about the design of their glasses is with performance in mind. I've spent my career studying the visual system and how it works, and I can tell you that ROKA glasses take into account the science of the visual system, such that whether or not you're wearing them on a very bright day or you walk into a shadowed area, or there's cloud cover, you can still see everything with perfect clarity. That also reflects the fact that the lenses that they use are of the absolute highest optical quality. The other terrific thing about ROKA sunglasses and eyeglasses is that they're designed to be worn in all conditions. You can use them while running, while cycling. Even if you get sweaty, they won't slip off. And they look great. One problem I have with a lot of so-called performance eyeglasses and sunglasses out there is that they look crazy. They make people look like cyborgs. ROKA glasses have a terrific aesthetic. You can wear them to dinner, you can wear them at work, and you can wear them in all sorts of sports activities. If you'd like to try ROKA glasses, you can go to ROKA, that's R-O-K-A, .com and enter the code Huberman to save 20% off your first order. That's ROKA, R-O-K-A, .com and enter the code Huberman at checkout. Today's podcast is also brought to us by InsideTracker. InsideTracker is a personalized nutrition platform that analyzes data from your blood and DNA to help you better understand your body and reach your health goals. I've long been a believer in getting regular blood work done for the simple reason that many of the factors that impact your immediate and long-term health can only be analyzed from a quality blood test. And nowadays, with the advent of DNA tests, you can also get insight into your immediate and long-term health by way of understanding your DNA. One issue with many DNA and blood tests, however, is that you get the numbers back about metabolic factors, hormones, genes, et cetera, but there's no directive as to what to do with that information. With InsideTracker, they have a very easy to use dashboard, and that dashboard not only gives you your numbers, but it gives you simple directives related to nutrition, supplementation, exercise, and other lifestyle factors that allow you to move those numbers into the ranges that are right for you and your health goals. If you'd like to try InsideTracker, you can go to insidetracker.com/huberman, and if you do that, you'll get 25% off any of InsideTracker's plans. Just use the code Huberman at checkout. Today's episode is also brought to us by Belcampo. Belcampo is a regenerative farm in Northern California that raises organic, grass-fed, and finished certified humane meats. I don't eat a lot of meat. I eat meat about once a day. But when I do, I make sure that it's high quality and both humanely and sustainably raised. Conventionally raised animals are confined to feedlots and eat a diet of inflammatory grains, but Belcampo's animals graze on open pastures and seasonal grasses, resulting in meat that's higher in nutrients and healthy fats. And I've talked many times before on this podcast about how getting sufficient levels of omega-3s is very important for metabolic health, hormone health, mood, essentially all aspects of one's health. Belcampo meats have high levels of omega-3s because of the grasses they feed on. The way Belcampo raises its animals isn't just better for our health, it also has a positive impact on the environment. They practice regenerative agriculture, which means that their meat is climate positive and carbon negative, meaning it's good for you and it's good for the environment. You can order Belcampo's sustainably raised meats to be delivered to you using my code Huberman by going to belcampo.com/huberman, and if you do that, you'll get 20% off your first order. I'm a big fan of their keto meatballs. I also really

3. 6:00 – 10:20

   What Is Sleep?

   1. AHAndrew Huberman6:00

      like their boneless rib eyes. I eat those pretty much once a day. Again, that's Huberman for the code, and it's belcampo.com/huberman for 20% off.... your order. And now my discussion with Dr. Matt Walker. Great to finally meet you in person.

   2. MWMatt Walker6:15

      Wonderful to connect, um, I mean, it's been too long, but I suspect it would have been a shorter time before we'd met lest the pandemic-

   3. AHAndrew Huberman6:23

      Yeah.

   4. MWMatt Walker6:24

      ... but, um, thank you for coming up here.

   5. AHAndrew Huberman6:25

      No, thank you. Yeah, I'm delighted that we're finally sitting down face-to-face. I've been tracking your work both in the internet sphere, and I read your book and loved it, and also from the perspective of science. You actually came to Stanford couple of years ago and gave a, uh, a lecture, uh, for Brain Mind, uh-

   6. MWMatt Walker6:43

      Oh, yeah. Yeah, yeah, yeah.

   7. AHAndrew Huberman6:45

      And, um, there, of course, uh, you talked about sleep and its utility and its challenges and how to, uh, and how to conquer it, so to speak. Um, let's start off very basic. What is sleep?

   8. MWMatt Walker6:59

      Sleep is probably the single most effective thing you can do to reset your brain and body health. So that's a functional answer-

   9. AHAndrew Huberman7:07

      Mm-hmm.

   10. MWMatt Walker7:07

       ... in terms of, you know, what is sleep in terms of its benefits. Sleep as a process, though, is an incredibly complex physiological ballet. And if you were to recognize or see what happens to your brain and your body at night during sleep, you would be blown away. And the paradox is that most of us, and I would think this too, you know, if I wasn't a sleep scientist, we go to bed, we lose consciousness for seven to nine hours, and then we sort of wake up in the morning and we generally feel better. And in some ways, that denies the physiological and biological beauty of sleep. So upstairs in your brain when you're going through these different stages of sleep, the, the changes in brain wave activity are far more dramatic than those that we see when we're awake. And we can speak about deep sleep and what happens there. REM sleep is a fascinating time, which is another stage of sleep often called dream sleep, which is rapid eye movement sleep. That stage of sleep, some parts of your brain are up to 30% more active than when you're awake. So again, it's kind of violating this idea that our mind is dormant and our body is just simply quiescent and, and resting. So I would happy to just sort of double click on either one of those and also what changes in the body as well, but it is an intense evolutionary adaptive benefit, um, and system. That said though, I, I would almost push back against, uh, an evolved system when we think about the question of sleep and what sleep is. Our assumption has always been that we evolved to sleep, and I've actually questioned that, and I have no way to get in a time capsule and go back and prove this, but what if we started off sleeping and it was from sleep that wakefulness emerged?

   11. AHAndrew Huberman9:05

       Mm-hmm.

   12. MWMatt Walker9:05

       Why do we assume that it's the other way around? And I think there's probably some really good evidence that sleep may have been the proto-state, that it was the basic fundamental living state, and when we became awake, as it were, we always had to return to sleep. You know, in some ways, at that point, sleep was the price that we paid for wakefulness, and that's another way of describing what sleep is. But again, I think it sort of denies that the active state of sleep, it's not a passive state of sleep either. Um, and then finally you can say what, what is sleep across different species? And in us human beings and in all mammalian species and avian species as well, sleep is broadly separated into these two main types, and we've got non-rapid eye movement sleep on the one hand and then we've got rapid eye movement sleep on the other. And we can speak about how they unfold across a night and their architecture because it's not just intellectually interesting from the perspective of what sleep is, it's also practically impactful for our daily lives, and I'd love to sort of go down that route too, but you navigate. You tell me.

   13. AHAndrew Huberman10:18

       Yeah, no-

   14. MWMatt Walker10:18

       I can-

   15. AHAndrew Huberman10:19

       Let's definitely go down

4. 10:20 – 16:15

   REM (Rapid Eye Movement) aka 'Paradoxical Sleep'

   1. AHAndrew Huberman10:20

      that route. So, um, you mentioned how active the brain is during certain phases of sleep. When I was coming up in science, REM sleep, rapid eye movement sleep, was referred to as paradoxical sleep.

   2. MWMatt Walker10:32

      Yeah.

   3. AHAndrew Huberman10:32

      Is that still a good way to think about it? Paradoxical because the brain is so active and yet we are essentially paralyzed, correct?

   4. MWMatt Walker10:38

      Yeah, it really-

   5. AHAndrew Huberman10:39

      Good.

   6. MWMatt Walker10:39

      ... is a paradox, and where that came from was simply the brain wave recordings-

   7. AHAndrew Huberman10:44

      Mm-hmm.

   8. MWMatt Walker10:45

      ... that if all I'm measuring about you is your brain wave activity, it's very difficult for me sitting outside of the sleep laboratory room to figure out are you awake or are you in REM sleep? Because those two patterns of brain activity are so close to one another, you can't discriminate between them. Yet the paradox is that when you are awake, I go in there and you're sort of sitting up, you're clearly conscious and awake, but yet when you go into REM sleep, you are completely paralyzed, and th- that's one of the... I, I think that's part of the paradox, but the paradox really just comes down to two dramatically different conscious states, yet brain activity is dramatically more similar than different, and the way I can figure out which of the two you are in is by measuring two other signals, the activity from your eyes and the activity from your muscles. So when we're awake, we will occasionally have these blinks and we'll have sort of saccades, but during REM sleep, you have these really bizarre horizontal shuttling eye movements that occur and that's where the name comes from, rapid eye movement sleep.

   9. AHAndrew Huberman11:58

      Are they always horizontal?

   10. MWMatt Walker12:00

       Mostly they are horizontal.

   11. AHAndrew Huberman12:02

       That's interesting.

   12. MWMatt Walker12:02

       And that's one of the ways that we can differentiate them from other waking eye movement activity 'cause it's not always l- it can be sometimes horizontal, but it can also have diagonal and also vertical in that plane.But then the muscle activity is the real dead giveaway. Just before you enter REM sleep, your brain stem, which is where the dynamics of non-REM and REM are essentially played out and then expressed upstairs in the cortex and downstairs in the body, um, when we go into REM sleep and just a few seconds before that happens, the brain stem sends a signal all the way down the spinal cord, and it communicates with what are called the alpha motor neurons in the spinal cord, which control voluntary skeletal muscles, and it's a signal of paralysis. And when you go into dream sleep, you are locked into a physical incarceration of your own body.

   13. AHAndrew Huberman12:59

       Amazing.

   14. MWMatt Walker13:00

       Uh, you know, why, why would Mother Nature do such a thing? And it's in some ways very simple. The brain paralyzes the body so that the mind can dream safely. Because think about how quickly we would have all been popped out of the gene pool, you know, if I think I'm, you know, one of the best skydivers who can just simply fly, and I've had sometimes those dreams too, you know, and I get up on my apartment window and I leap out-

   15. AHAndrew Huberman13:27

       Mm-hmm. You're done.

   16. MWMatt Walker13:28

       ... you're done-

   17. AHAndrew Huberman13:29

       Yeah.

   18. MWMatt Walker13:29

       ... you know?

   19. AHAndrew Huberman13:30

       Yeah.

   20. MWMatt Walker13:30

       So that's one of the sort of, that's part of the paradox of REM sleep, both its brain activity similarity despite the behavioral state being so different, and this bizarre lockdown of the, the sort of brain, of the body itself. Now, of course, the involuntary muscles thankfully aren't, um, paralyzed, so you keep breathing, your heart keeps beating.

   21. AHAndrew Huberman13:52

       Is this why men have erections during REM sleep and women have vaginal lubrication during sleep?

   22. MWMatt Walker13:58

       That's one of the reasons. Part of the other reason, though, there is because of the autonomic activity. So there is a nervous, a part of our nervous system called the autonomic nervous system-

   23. AHAndrew Huberman14:08

       Mm-hmm.

   24. MWMatt Walker14:08

       ... and it controls many of the automatic behaviors, and some of those are aspects of our reproductive facilities. During REM sleep, what we later discovered is that you go through these bizarre what we call autonomic storms, which sounds dramatic, but it actually is when you measure them, that you'll go through periods where your heart rate decelerates and drops and your blood pressure goes down, and then utterly randomly, your heart rate accelerates dramatically, and what we call the fight or flight branch of the autonomic nervous system, or the sympathetic nervous system, badly named 'cause it's anything but sympathetic, it's very aggravating (laughs) , um, that all of a sudden fires up, and then it shuts down again. And it's not in any regular way, and it's when you get those autonomic storms you get very activated from a physiological perspective, that you can have these erections and you have vaginal discharge, et cetera.

   25. AHAndrew Huberman15:04

       But you're totally paralyzed?

   26. MWMatt Walker15:05

       But you are still paralyzed.

   27. AHAndrew Huberman15:07

       Wow.

   28. MWMatt Walker15:07

       There are only, um, two voluntary scoli- uh, two voluntary muscle groups that are spurred from the paralysis. Bizarre. One, your extraocular muscles-

   29. AHAndrew Huberman15:20

       Mm-hmm.

   30. MWMatt Walker15:20

       ... because if they were paralyzed, you wouldn't be able to have rapid eye movements.
5. 16:15 – 24:00

   Slow Wave Sleep aka 'Deep Sleep'

   1. AHAndrew Huberman16:16

      I would imagine that there are states in waking that also resemble slow wave sleep, or rather that-

   2. MWMatt Walker16:23

      Hmm.

   3. AHAndrew Huberman16:23

      ... there are states, that slow wave sleep also resembles waking states. You've beautifully illustrated how REM sleep can mimic some of the more active brain states that we achieve in waking. What sort of waking state that I might have experienced, or experience on a daily basis, might look similar to slow wave sleep, non-REM sleep, if any?

   4. MWMatt Walker16:43

      Uh, it's a genius way of thinking about it, turns the tables, I love it. Um, we almost never see anything like the, the true ultra slow waves of deep non-REM sleep. So, um, we spoke about these two stages, non-REM and REM. Um, non-REM is further subdivided into four separate stages-

   5. AHAndrew Huberman17:02

      Mm-hmm.

   6. MWMatt Walker17:03

      ... um, stages one through four, increasing in their depth of sleep. So stages three and four, that's what we typically call deep non-REM sleep. Stages one and two, light non-REM.

   7. AHAndrew Huberman17:11

      So maybe take me through the arc of a night, just so that, um-

   8. MWMatt Walker17:14

      Yeah, yeah.

   9. AHAndrew Huberman17:14

      ... so I, I put my head down, uh, well, for you, what, what time do you normally go to sleep?

   10. MWMatt Walker17:18

       So I'm usually sort of around about a 10:30 PM guy, and usually I'll naturally wake up sort of a little bit before 7:00, sometimes before 6:45 or 7:00. I have an alarm set for, um, 7:04, um, AM, um-

   11. AHAndrew Huberman17:34

       You heard it here, folks.

   12. MWMatt Walker17:35

       (laughs)

   13. AHAndrew Huberman17:35

       Matt Walker does use an alarm clock.

   14. MWMatt Walker17:37

       I rarely, rarely, I'm usually sort of-

   15. AHAndrew Huberman17:39

       He doesn't recommend it, but he does use it.

   16. MWMatt Walker17:41

       Yeah, I usually sort of-

   17. AHAndrew Huberman17:41

       You're, you're human after all.

   18. MWMatt Walker17:42

       Oh, I am so human, um, and, and I've had my sleep issues, and I'd love to speak about that too, but, um, it's only just, you know, in the event that-

   19. AHAndrew Huberman17:52

       Mm-hmm.

   20. MWMatt Walker17:52

       ... um, you know, 'cause I like to keep regularity too. You've got to keep those-

   21. AHAndrew Huberman17:55

       Sure.

   22. MWMatt Walker17:55

       ... two things in balance. And 7:04 just because, you know, why not be idiosyncratic? Uh, I don't know-

   23. AHAndrew Huberman18:01

       Love it.

   24. MWMatt Walker18:01

       ... why we always set things, uh, on these, uh, hard numbers. So yep, so when you and I-

   25. AHAndrew Huberman18:06

       So, so you go to sleep around 10:30.

   26. MWMatt Walker18:08

       Yup.

   27. AHAndrew Huberman18:08

       So using you as an example, um, because I imagine a number of people go to sleep at different times, but 10:30 is about when I go to sleep, 11:00 is for me, but, um, so you go to sleep at 10:30. So for that first...... um, let's say, three hours of sleep. Wh- what does the architecture of that sleep look like as compared to the last three hours of your sleep, uh, before morning?

   28. MWMatt Walker18:28

       Yeah. So, I should note that that sort of, you know, 10:30 to 7:00, that's just based on my chronotype and my-

   29. AHAndrew Huberman18:35

       Mm-hmm.

   30. MWMatt Walker18:35

       ... preferential. It's different for different people. I'm not-
6. 24:00 – 32:20

   Compensating For Lost Sleep

   1. AHAndrew Huberman24:00

      digression of... I have one question, which is, you're saying that as across the night, a greater percentage of these 90-minute cycles are going to be occupied by REM sleep as you progress through the night. I'm aware that there, uh, based on work that you've done and, and, uh, and from your public education efforts and others, um, that-We have so-called circadian forces, and we have other forces that are driving when we sleep and when we wanna sleep, et cetera. Without going into the details of those, I have a simple question. The experiment is the following. Let's say, God forbid, you are prevented from going to sleep at your normal time-

   2. MWMatt Walker24:38

      Yeah.

   3. AHAndrew Huberman24:38

      ... and you stay up for the four hours or five hours that normally you would be in predominantly slow wave sleep.

   4. MWMatt Walker24:45

      Yeah.

   5. AHAndrew Huberman24:46

      If, let's say, you finally get to lie down at 3:00 AM, a time when normally your sleep would be occupied mostly by rapid eye movement sleep-

   6. MWMatt Walker24:56

      Yeah.

   7. AHAndrew Huberman24:57

      ... will you experience a greater percentage of rapid eye movement sleep because of these so-called circadian forces, meaning that's what's appropriate for that time? Or will your system need to start at the beginning of the race that we're ref-

   8. MWMatt Walker25:11

      (laughs)

   9. AHAndrew Huberman25:11

      ... that as I, as I'm referring to it-

   10. MWMatt Walker25:12

       Yeah.

   11. AHAndrew Huberman25:12

       ... that we're calling sleep?

   12. MWMatt Walker25:14

       Yeah.

   13. AHAndrew Huberman25:14

       If we're, if that's not clear to anybody, basically what I'm asking is if you are forced to skip the slow wave sleep part of the night, will your system leap into rapid eye movement sleep or does it have to start at the beginning and get slow wave sleep first? In other words, does one sleep state drive-

   14. MWMatt Walker25:30

       Yeah.

   15. AHAndrew Huberman25:30

       ... the entry to the next sleep state?

   16. MWMatt Walker25:32

       Great question. So there is some degree of reciprocity between the sleep states, I should note, that when we drive one of those up, we often but not always see a, a change in the other. There are some pharmacologies that have shown an independence to that, and we've also played around with things like temperature. And sometimes you can, you know, nudge one and not seem to upset or perturb the other.

   17. AHAndrew Huberman25:58

       Mm-hmm.

   18. MWMatt Walker25:58

       But to your, um, I think lovely point, th- the answer is it's a mix, but it's mostly the latter, meaning you will mostly go into your REM sleep phases and be significantly deficient in your deep sleep. So just because I start my sleep cycle at 3:00 AM rather than at 10:30 PM, it doesn't mean that my brain just says, "Well, I've got a program, and I'm just going to run the program, and the way the program runs is that we always start with a first couple of hours of deep sleep. So we're just gonna begin act number one, scene one." It doesn't do that. Now, I will get some deep sleep to begin with, and part of that is just because of how sleep works based on how long I've been awake. The longer I'm awake, there is a significantly greater pressure for deep sleep. But we actually use exactly what you just described as an experimental technique to selectively deprive people of one of those stages of sleep or the other. So we will do first half of the night deprivation, and then let you sleep the second half, so that means that you will be mostly deep sleep deprived and you will still get mostly all of your REM sleep.

   19. AHAndrew Huberman27:15

       Mm-hmm.

   20. MWMatt Walker27:15

       And then we switch it so you only get your first four hours, which means you will mostly get deep non-REM sleep, but you will get almost no REM sleep. So in both of those groups, they've both had four hours of sleep, so the difference between them in terms of an experimental outcome is not the sleep time because they've both slept for the same amount, it's the contribution of those different stages. Now, we actually have more elegant methods for sort of selectively going in there and scooping out different stages of sleep, but that's the way we used to do it old school, was just using this timing difference.

   21. AHAndrew Huberman27:49

       And who suffers more, those that lack the early phase or those that lack the later phase of the night sleep? In other words, sh- if I have to sleep only four hours for whatever reason, am I better off getting the early part of the night sleep or the l- second half of the night sleep?

   22. MWMatt Walker28:05

       Depends on what y- the outcome measure is. Eh.

   23. AHAndrew Huberman28:07

       Um, so that gets right to the differences between slow wave sleep and REM.

   24. MWMatt Walker28:11

       Right.

   25. AHAndrew Huberman28:11

       Uh, I was, um, probably misinformed, but my understanding, a very crude understanding I should, I should say before, um-

   26. MWMatt Walker28:18

       I very much doubt it.

   27. AHAndrew Huberman28:19

       ... which is-

   28. MWMatt Walker28:19

       Au contraire with someone like you.

   29. AHAndrew Huberman28:21

       Was it... Uh, which is, that, that, very nice of you, but the, the, the first part of the night, the slow wave sleep, is restorative to the musculature, to motor learning, and that the dream content tends to be less emotional. The second half of the night being more emotional dreams and sort of the unpairing of the emotional load of our previous day and other experiences. So, in other words, if I were to deprim myself, deprive myself, excuse me, of REM, I would be hyperemotional, not, maybe not as settled with m- the kind of experiences of my life, whereas if I had to deprive myself of slow wave sleep, I would, um, feel a f- a more physical malaise. Is that correct or is that far too simple? And if it is too simple, please, uh, tell me where I'm wrong.

   30. MWMatt Walker28:59

       No, I think much of that is correct, and it's sort of that plus.
7. 32:20 – 39:48

   Waking in the Middle Of The Night

   1. MWMatt Walker32:20

      um ...

   2. AHAndrew Huberman32:20

      Yeah, it's a- it's incredible. I wanna introduce a- another, um, gedankenexperiment, another thought experiment. So in this arc of the night, uh, slow wave sleep predominates, uh, early in the night, and then REM sleep. There's a scenario that many people, including myself, experience on a regular basis which is, they go to sleep, sleeping just fine, three, four hours into it, they wake up.

   3. MWMatt Walker32:43

      Yeah.

   4. AHAndrew Huberman32:43

      They wake up for whatever reason, maybe there was a noise, maybe the temperature isn't right. We will certainly talk about sleep hygiene, et cetera. They get up, they go to the restroom, they might flip on the lights, they might not. They'll get back in bed, hopefully they're not picking up their phone and-

   5. MWMatt Walker32:59

      (laughs)

   6. AHAndrew Huberman33:00

      ... starting to browse and wake up the brain through various mechanisms, light and cognitive stimulation, et cetera. They go back to sleep. Let's say after about 10, 15 minutes they're able to fall back asleep and then they sleep till their more typical wake time.

   7. MWMatt Walker33:12

      Yeah.

   8. AHAndrew Huberman33:14

      How detrimental is that wake up episode or, or, um, event in terms of longevity, learning, et cetera? I would love to sleep the entire night through every night-

   9. MWMatt Walker33:27

      Yeah.

   10. AHAndrew Huberman33:27

       ... but most nights I don't, and yet I feel pretty good throughout the day-

   11. MWMatt Walker33:32

       Yup.

   12. AHAndrew Huberman33:32

       ... some days better than others.

   13. MWMatt Walker33:33

       Yeah.

   14. AHAndrew Huberman33:33

       So if you were to kind of evaluate that waking episode and compare it to sleeping the whole night through, what are your, what are your thoughts on that?

   15. MWMatt Walker33:44

       So I think if you're waking up sort of frequently as you're describing, um, I would probably get your estate in order because my guess is within the next year you're gonna be, you're gonna be done for. (laughs) No, I'm kidding you. Absolutely kidding you. It is perfectly natural and normal-

   16. AHAndrew Huberman34:01

       Mm-hmm.

   17. MWMatt Walker34:01

       ... particularly as we progress with age. You know, children tend to have, um, typically more continuous sleep. Now, it's not that they aren't waking up for brief periods of time, they are, and in fact we all do. When we come out the other end of our sleep cycle at the end of our REM sleep period of the 90-minute cycle, almost everybody wakes up and we make a postural movement.

   18. AHAndrew Huberman34:25

       Mm-hmm.

   19. MWMatt Walker34:25

       We turn over because we've been paralyzed for so long and the body will also like to shift its wake position.

   20. AHAndrew Huberman34:30

       Do we ever look around? Do we ever open our eyes and look around?

   21. MWMatt Walker34:34

       You ... Some- sometimes people will open their eyes, but usually it's only for a brief period of time and they usually never commit those awakenings to memory.

   22. AHAndrew Huberman34:42

       Right.

   23. MWMatt Walker34:44

       Your situation, and it's my situation as well, I usually now at this stage of life I don't sleep through the night, I'll usually have a bathroom, uh, break and then I'll come back. That's perfectly normal. We tend to forget that in sleep science we think of sleep efficiency, so of the total amount of time that you're in bed, how much of that percent time is spent asleep? And we usually look to numbers that are above 85% or more as a healthy sleep efficiency.

   24. AHAndrew Huberman35:18

       Mm-hmm.

   25. MWMatt Walker35:19

       So if you were to think about me going to bed and I spend, you know, let's say eight and a quarter, eight and a half hours of time in bed with a normal healthy sleep efficiency, I still may be only sleeping a total of seven and a half hours or seven and three quarter hours, meaning that I'm going to be awake in total, not in one long bout, but I'm going to be awake for upwards of 30 minutes net some time.

   26. AHAndrew Huberman35:51

       Mm-hmm.

   27. MWMatt Walker35:51

       Sometimes that can be after a 10 minute, you know, dalliance after having gone to the bathroom and I'm just gradually drifting back off again. Other times it will just be for a couple of minutes, and most of those you don't commit. So I think we need to stop ... We don't need to get too worried about, you know, periods of time awake just because we're not sleeping throughout the night. I would love to do that too, and I remember when I ... That used to happen, and it still happens, you know, occasionally.

   28. AHAndrew Huberman36:18

       Every once in a while. It feels great when it does happen.

   29. MWMatt Walker36:19

       And, and it's, it's a lovely thing, but-

   30. AHAndrew Huberman36:21

       It's a surprise, right?
8. 39:48 – 42:48

   Uberman (Not Huberman!) Sleep Schedule

   1. AHAndrew Huberman39:48

      to raise something about the so-called Uberman schedule, not-

   2. MWMatt Walker39:53

      (laughs)

   3. AHAndrew Huberman39:53

      ... to be confused with the Huberman-

   4. MWMatt Walker39:55

      Huberman.

   5. AHAndrew Huberman39:55

      ... schedule.

   6. MWMatt Walker39:56

      Yeah.

   7. AHAndrew Huberman39:56

      Um, fortunately no one, uh, has confused those yet.

   8. MWMatt Walker39:59

      (laughs)

   9. AHAndrew Huberman40:00

      Um, the, some years ago there was a discussion about the so-called Uberman schedule, meaning the Superman schedule, so that's Huberman without an H.

   10. MWMatt Walker40:08

       (laughs)

   11. AHAndrew Huberman40:08

       Which I have nothing to do with. Um, if you read your Nietzsche, this mi- w- this will have a subtext, but regardless-

   12. MWMatt Walker40:14

       (laughs)

   13. AHAndrew Huberman40:15

       ... um, the Uberman schedule, as I understand, is one in which, um, the person elects to sleep in 90-minute bouts spread throughout the day and night-

   14. MWMatt Walker40:25

       Right.

   15. AHAndrew Huberman40:25

       ... in an attempt to get more productivity, um, and/or reduce their overall sleep need. There was a paper published recently that explored whether or not this is good or bad for us. Maybe you just, uh, give us the take home message on that.

   16. MWMatt Walker40:38

       Yeah, so these Uberman-like, uh, schedules, and there's lots of different forms of that, they try to essentially pie chart the 24-hour period into short bouts of sleep with some shorter, or no, well, slightly longer periods of wakefulness, then short bouts of sleep, then wakefulness. It, you know, you're, I sort of made it a, a I think a quip, it's almost like you're sleeping like a baby, you know?

   17. AHAndrew Huberman41:04

       Mm-hmm.

   18. MWMatt Walker41:04

       'Cause that's the way that babies-

   19. AHAndrew Huberman41:05

       Yeah, nine, in 90-minute naps.

   20. MWMatt Walker41:06

       ... w- will sleep.

   21. AHAndrew Huberman41:07

       Yeah.

   22. MWMatt Walker41:07

       That they will have, you know, these-

   23. AHAndrew Huberman41:08

       Yeah.

   24. MWMatt Walker41:08

       ... brief naps, then they're awake-

   25. AHAndrew Huberman41:09

       Yeah.

   26. MWMatt Walker41:09

       ... then they're asleep, then they're awake, and to the chagrin of parents, across the night it's basically the same, they're awake, they're asleep, they're awake, they're asleep. And that's more the, the schedule that these types of protocols have, um, have suggested. And there was a really great comprehensive review that found not only that they weren't necessarily helpful, but they were actually really quite detrimental. And on almost every performance metric, whether it be task performance, whether it be physiological outcome measures, whether it even be the quality of the sleep that they were having when they were trying to get it, all of those were in a downward direction. And it's not surprising-

   27. AHAndrew Huberman41:50

       Yeah.

   28. MWMatt Walker41:50

       ... if you look at your, the way that your physiology is programmed, if you look at the way your circadian rhythm is programmed, none of that screams to us that we should be sleeping in that way. Uh-

   29. AHAndrew Huberman42:02

       Well, I'm chuckling because, uh, we always hear, "Sleep like a baby." This is how babies sleep. And, uh-

   30. MWMatt Walker42:06

       Right.
9. 42:48 – 49:20

   Viewing Morning SUNLight

   1. AHAndrew Huberman42:48

      a vision scientist I've been very excited by the work on these, uh, non-image forming cells in the eye, the so-called melanopsin cells-

   2. MWMatt Walker42:53

      Yeah.

   3. AHAndrew Huberman42:53

      ... that inform the brain about ti- circadian time of day. And I'm a big proponent of people getting, uh, some sunlight, ideally sunlight, but other forms of bright light into their eyes early in the day and when they want to be awake.

   4. MWMatt Walker43:06

      Yep.

   5. AHAndrew Huberman43:06

      Essentially during the phase of their 24-hour circadian cycle when temperature is rising, and then starting to get less light in their eyes-... as our temperature is going down in term- later in the day and in the evening. Are there any adjustments to that general theme that you'd like to add or is, um, in any way?

   6. MWMatt Walker43:25

      No. I think that's exactly what we recommend right now, which is try to get at least 30 to 40 minutes of exposure to some kind of natural daylight. Now, there may be parts of the world where, you know, it's-

   7. AHAndrew Huberman43:38

      Yeah. You're from-

   8. MWMatt Walker43:39

      ... it- it's-

   9. AHAndrew Huberman43:39

      ... you're from a rather cloudy part of the world.

   10. MWMatt Walker43:41

       I am from, yeah, uh, Liverpool, England.

   11. AHAndrew Huberman43:44

       Oh.

   12. MWMatt Walker43:44

       Uh, and, uh, the northwest of England is not known for its, um, beach resorts-

   13. AHAndrew Huberman43:49

       Mm-hmm.

   14. MWMatt Walker43:49

       ... and fine weather. Uh, I, I remember I'd sort of... I went back home for a trip when I'd first been out, uh, in California, and I thought, "Why is the sky so low?" You know? (laughs) It was just, you know, constantly out. We joke that in, um, in the UK we usually have nine months of bad weather and then three months of winter, and that- that's your, that's your entire year-

   15. AHAndrew Huberman44:14

       Oh my gosh.

   16. MWMatt Walker44:14

       ... of, uh, in terms of a climate. But to come to your point, you're exactly right, try to get that daylight. Now, it can be, you know, working next to a window and you're getting that natural sunlight, but that natural sunlight is, even on a cloudy day in England, is f- usually far more potent than anything that you'll get from indoor lighting despite you thinking sort of from a perception-wise, maybe they're- they're much closer than I would think.

   17. AHAndrew Huberman44:40

       Yeah. I've been, um... Sorry to interrupt. I've been a-

   18. MWMatt Walker44:42

       Oh, no.

   19. AHAndrew Huberman44:43

       ... a big proponent of, there's a- an app called Light Meter which will, it's a free app, uh, I have nothing to do with it, that will allow you to, uh, get a pretty decent measurement of the amount of- of light energy coming toward you. And if you, um, hold it up to a cloudy morning where you don't think it's very bright out, kind of a dismal day, you'll notice that there'll be 1,000, 2,000, even, you know, 5,000 lux, lux just being a measure of brightness, of course. And then you can point the same light meter toward an indoor light that seems very bright and very intense-

   20. MWMatt Walker45:10

       (laughs)

   21. AHAndrew Huberman45:10

       ... and it'll say 500 lux.

   22. MWMatt Walker45:12

       Yes, sir.

   23. AHAndrew Huberman45:13

       And you realize that the intensity as we gauge it perceptually is not really what the system is receiving, so outdoor light is key. How do you w- w- how do you get this natural stimulation or, um, l- I should just say light stimulation early in the day? What- what is your typical... What does Matt Walker do to get this light stimulation?

   24. MWMatt Walker45:31

       (laughs) I am no poster child, but, um, usually I will, um, if I'm working out, I usually work out most days, um, and I shopped around and I found a gym that has huge amounts of window exposure facing to the east. This is sound, this is gonna sound so, uh, ridiculous, you know, Matt Walker chooses a gym on the basis of-

   25. AHAndrew Huberman45:51

       I love it.

   26. MWMatt Walker45:51

       ... the solar input so he can-

   27. AHAndrew Huberman45:53

       Well-

   28. MWMatt Walker45:53

       ... you know, correct his circadian-

   29. AHAndrew Huberman45:54

       ... there are a lot of criteria for selecting gyms.

   30. MWMatt Walker45:56

       Uh-
10. 49:20 – 1:07:54

    Caffeine

    1. AHAndrew Huberman49:20

       the lines of wakefulness, I have a number of questions about caffeine.

    2. MWMatt Walker49:24

       Yeah.

    3. AHAndrew Huberman49:24

       The dreaded and beloved caffeine.

    4. MWMatt Walker49:26

       Yeah.

    5. AHAndrew Huberman49:26

       I love caffeine, but I like it in relatively s- um, restricted periods of time. So, um, I'm a big fan of waking up and, even though I wake up very groggy, allowing my natural wakefulness signals to take hold, meaning I wake up very slowly but I don't drink caffeine right away.

    6. MWMatt Walker49:47

       Yeah.

    7. AHAndrew Huberman49:47

       I sort of delay caffeine by a li- a little while, usually 90 minutes to two hours.

    8. MWMatt Walker49:53

       Okay.

    9. AHAndrew Huberman49:53

       And that idea came to me on the basis of my understanding of how caffeine and the a- adenosine receptor interact. I have a feeling you're going to pronounce adenosine differently than I do. (laughs)

    10. MWMatt Walker50:04

        No, no, no, I will go with-

    11. AHAndrew Huberman50:05

        (laughs)

    12. MWMatt Walker50:05

        I will go with adenosine.

    13. AHAndrew Huberman50:06

        I'll, I'll t- try to go with your skeletal instead of skeletal...

    14. MWMatt Walker50:09

        (laughs)

    15. AHAndrew Huberman50:10

        ... and synapse in synapse. Um, but-

    16. MWMatt Walker50:11

        I'll be shedule on schedule.

    17. AHAndrew Huberman50:12

        There we go. But, um, but to make it really simple for folks, how does caffeine work to make us feel more alert? And does the timing in which we ingest caffeine play an important role in whether or not it works for us or against us? So maybe we just start with h- how, how does caffeine work? Why is it that when I drink mate or coffee, which are my preferred sources of caffeine, do I feel a mental and physical lift?

    18. MWMatt Walker50:40

        Yeah. So I'm going to suggest counter to what most people would think, drink coffee. (laughs)

    19. AHAndrew Huberman50:48

        (laughs)

    20. MWMatt Walker50:48

        Which is-

    21. AHAndrew Huberman50:48

        Or mate, is mate okay also?

    22. MWMatt Walker50:50

        Y- yeah, yeah, yeah.

    23. AHAndrew Huberman50:50

        Or whatever form you enjoy, yeah.

    24. MWMatt Walker50:52

        We'll, we'll come on to sort of why I suggest that but when it comes to coffee, uh, I would say the dose and the timing makes the poison.

    25. AHAndrew Huberman51:02

        Mm-hmm.

    26. MWMatt Walker51:03

        So let's start with how caffeine works. Um, caffeine is in a class of drugs that we call the psychoactive stimulants. So it works through a variety of mechanisms, um, one is a dopamine mechanism. Dopamine we often think of as a reward chemical or, um, but dopamine is also very much an alerting neurochemical as well. And caffeine has some role it seems to play in increasing dopamine, but its principal mode of action we believe, in terms of making me more alert and keeping me awake throughout the day, is on the effects of adenosine. And to explain what adenosine is, from the moment that you and I woke up this morning, this chemical adenosine has been building up in our brain. And the longer that we're awake, the more of that adenosine accumulates.

    27. AHAndrew Huberman51:55

        Is it, um, may I ask, is it accumulating in neurons, in glia, or in the blood vessels? Where and, and is it also accumulating in my body? Where is this a- adenosine coming from and where is it accumulating?

    28. MWMatt Walker52:08

        Yeah, so the adenosine here that we're talking about that is creating the sleep pressure is a central brain phenomenon, and it comes from the neurons themselves combusting energy.

    29. AHAndrew Huberman52:18

        Mm-hmm.

    30. MWMatt Walker52:19

        And as they're combusting energy, one of the offshoots of that is this chemical adenosine.
11. 1:07:54 – 1:14:30

    Alcohol

    1. AHAndrew Huberman1:07:54

       want to talk about alcohol-

    2. MWMatt Walker1:07:55

       Yeah.

    3. AHAndrew Huberman1:07:55

       ... because I think caffeine and alcohol represent the, uh, the kind of two opposite ends of the spectrum. Clearly, there are other stimulants. Um, they're your Adderalls and your, uh, high energy drinks that people uses. But alcohol and caffeine are, are the most commonly consumed-

    4. MWMatt Walker1:08:09

       Yeah.

    5. AHAndrew Huberman1:08:10

       ... stimulants and, and sedatives, depressants as they're sometimes called. So, um, what happens when somebody has a glass, uh, th- we always hear a glass or two of wine in the evening or a, or a, uh, a cocktail after dinner-

    6. MWMatt Walker1:08:26

       Yeah.

    7. AHAndrew Huberman1:08:26

       ... or before dinner. How does that impact their sleep? And then we'll be sure to circle back in terms of what is reasonable ranges of behavior when it comes to, uh, avoiding alcohol or in- if it's age appropriate, et cetera-

    8. MWMatt Walker1:08:41

       (laughs)

    9. AHAndrew Huberman1:08:41

       ... enjoying alcohol.

    10. MWMatt Walker1:08:43

        Yeah. So alcohol, if we're thinking about classes of drugs, they're in a class of drugs that we call the sedatives, and I think one of the first problems that people often mistake, alcohol is often used as a sleep aid for people who are struggling with sleep when things like over-the-counter remedies, et cetera, or herbal remedies have just not worked out for them, and alcohol, unfortunately, is anything but a sleep aid. The first reason that most people use it is to try and help them fall asleep.

    11. AHAndrew Huberman1:09:13

        So do- and this process of this event I- that we call falling asleep, I have to imagine is a process-

    12. MWMatt Walker1:09:19

        It is a process.

    13. AHAndrew Huberman1:09:20

        ... like everything in biology.

    14. MWMatt Walker1:09:21

        Yeah.

    15. AHAndrew Huberman1:09:21

        And that that process involves, in some way t- as we talked about push-pull before, turning off thinking, planning-

    16. MWMatt Walker1:09:28

        Yep.

    17. AHAndrew Huberman1:09:28

        ... et cetera, and turning on some sort of relaxation mechanism. I have to imagine that these two things are knobs turning in opposite directions-

    18. MWMatt Walker1:09:36

        That's right.

    19. AHAndrew Huberman1:09:36

        ... that gives us this outcome we call falling asleep. Alcohol, it seems, is helpful for some people to turn off their thoughts or their planning.

    20. MWMatt Walker1:09:45

        Right, yeah.

    21. AHAndrew Huberman1:09:45

        Is that right?

    22. MWMatt Walker1:09:46

        Y- y- yes, it is. And so I think, you know, if we look at the pattern of brain activity, if I were to place you inside an MRI scanner where we're looking at the activity of your brain and watch you drifting off, some parts of your brain will become less active, other parts will become more active, and this is the push-pull model. It's inhibition, excitation. But alcohol is quite different in that regard. Alcohol is, because it's a sedative, what it's really doing is trying to essentially knock out your cortex. It's sedating your cortex, and sedation is not sleep, but when we have a couple of drinks in the evening, when we have a couple of nightcaps, we mistake sedation for sleep saying, "Well, I always, when I have a, like a couple of whiskeys or a couple of cocktails, it always helps me fall asleep faster." In truth, what's happening is that you're losing consciousness quicker, but you're not necessarily falling naturalistically asleep any quicker, so that's one of the first sort of things just to keep in mind. The second thing with alcohol is that it fragments your sleep, and we spoke about the quality of your sleep being just as important as the quantity, and alcohol through a variety of mechanisms, uh, some of which are activation of that autonomic nervous system, that fight or flight branch of the nervous system. Alcohol will actually have you waking up many more times throughout the night, so your sleep is far less continuous. Now, some of those awakenings will be of conscious recollection the next day. You'll just remember waking up. Many of them won't be, and so but yet your sleep will be littered with these sort of punctured awakenings throughout the night, and again, when you wake up the next morning, you don't feel restored by your sleep. You know, fragmented sleep or non-continuous sleep in this alcohol-induced way is usually not good quality sleep that you feel great on the next day. The, the third part of alcohol in terms of an equation is that it's quite potent at blocking your REM sleep, your rapid eye movement sleep, and REM sleep is critical for a variety of cognitive functions, um, some aspects of learning and memory. It seems to be critical for aspects of emotional and mental health.

    23. AHAndrew Huberman1:12:03

        You've described it before as a sort of self-generated therapy that occurs while we sleep

    24. NANarrator1:12:08

        ... which-

    25. MWMatt Walker1:12:08

        Yeah, it's overnight therapy, you know? It's emotional first aid, uh, is, is REM sleep.

    26. AHAndrew Huberman1:12:12

        Well, certainly people that don't get enough sleep, um, are very easy to derail emotionally.

    27. MWMatt Walker1:12:17

        Yeah.

    28. AHAndrew Huberman1:12:17

        Um, not that one would want to do that to people, but we all sort of fall apart emotionally. Our, I, I, I always think about it's almost like our skin sensitivity can be heightened-

    29. MWMatt Walker1:12:27

        Yes, absolutely.

    30. AHAndrew Huberman1:12:27

        ... when we are sleep deprived. Um, our emotional sensitivity, um, is such that when we're sleep deprived, uh, such that it takes a, um, much finer grain of sandpaper to create that kind of friction.
12. 1:14:30 – 1:16:14

    Growth Hormone & Testosterone

    1. MWMatt Walker1:14:30

       But what was also interesting, because REM sleep, as we spoke about before, is a time when some hormonal systems are essentially recharged and refreshed, growth hormone being one of them, there was well over a 50%, five zero, drop in their growth hormone release during alcohol-laced sleep at night.

    2. AHAndrew Huberman1:14:49

       Wow. Wow.

    3. MWMatt Walker1:14:50

       You know?

    4. AHAndrew Huberman1:14:50

       And growth hormone is so vital for metabolism and repair of tissues-

    5. MWMatt Walker1:14:54

       Yeah. Yeah.

    6. AHAndrew Huberman1:14:54

       ... and, um-

    7. MWMatt Walker1:14:55

       It's not just for kids.

    8. AHAndrew Huberman1:14:55

       ... keeping the body fat low and-

    9. MWMatt Walker1:14:57

       This is essential in adults, yeah.

    10. AHAndrew Huberman1:14:58

        It's essential. It's essential. Um, along those lines, I, I just wanna highlight the fact that this, um, this information that you're sharing, that growth hormone is released, is strongly tethered to the presence of healthy amounts of REM sleep is interesting to me because I always thought that growth hormone was released in the early part of the night.

    11. MWMatt Walker1:15:18

        Well, it is released, uh, in-

    12. AHAndrew Huberman1:15:19

        Mm-hmm.

    13. MWMatt Walker1:15:20

        ... across both of those, but ac- across the different stages. But what we also know is that when you disrupt REM sleep, there are those growth hormone consequences.

    14. AHAndrew Huberman1:15:29

        I see.

    15. MWMatt Walker1:15:29

        So it's not an exclusive, uh, system. Just like with testosterone, we can see changes throughout non-REM sleep, but if you ask when are the peak release rates of testosterone, it's right before we go into REM sleep and then during REM sleep.

    16. AHAndrew Huberman1:15:44

        And of course, re- testosterone being important both for, for males and for females.

    17. MWMatt Walker1:15:48

        For men and women, yeah.

    18. AHAndrew Huberman1:15:48

        Right? For libido and tissue repair and wellbeing.

    19. MWMatt Walker1:15:51

        Yeah.

    20. AHAndrew Huberman1:15:51

        Nobody, regardless of chromosomal, hormonal, or any other background, wants to have their normal levels of testosterone reduced acutely.

    21. MWMatt Walker1:16:00

        No.

    22. AHAndrew Huberman1:16:00

        That's just a bad ... It, it, it equates to a terrible set of psychological and physical symptoms.

    23. MWMatt Walker1:16:05

        Yeah, and the mortality risk that's associated with low testosterone is non-trivial.

    24. AHAndrew Huberman1:16:09

        Prostate cancer.

    25. MWMatt Walker1:16:10

        Right, exactly.

    26. AHAndrew Huberman1:16:11

        Yeah, yeah.

    27. MWMatt Walker1:16:11

        You know? So coming

13. 1:16:14 – 1:20:40

    Emotions, Mental Health & Longevity

    1. MWMatt Walker1:16:14

       back to just the point on REM sleep that you mentioned regarding emotional instability, and we see that, that's one of the things, one of the most reliable signatures of just insufficient sleep. Doesn't have to be sleep deprivation. What we've discovered over the past 20 years here at the Sleep Center is that there is no major psychiatric disorder that we can find in which sleep is normal. And so I think that firstly told us there is a very intimate association between your emotional and mental health and your sleep health. But when it also comes to REM sleep, I think what's fascinating is that it's not just about your emotional health. It's not just about your hormonal health. Um, we've also been seeing other aspects of, you know, cognition. But then there was a, a report, I think it could have been about two years ago, f- out of Harvard. Um, I think it was Beth, uh, Clearman's group. Um, they found that, and they replicated it in two different large populations. If you look at the contribution of different s- sleep stages to your lifespan, REM sleep was the strongest predictor of your longevity. And it was a linear relationship. It wasn't sort of one of these U-shaped or J-shaped curves that we often see with total sleep and mortality risk. It really was linear, that the less and less REM sleep that you were getting, the higher and higher your probability of death. And then they did-

    2. AHAndrew Huberman1:17:45

       Was that death due to, um, natural causes or accidents?

    3. MWMatt Walker1:17:47

       It was-

    4. AHAndrew Huberman1:17:47

       'Cause I could imagine if you're not getting enough REM sleep, you're more likely to drive off the freeway, step off a cliff or-

    5. MWMatt Walker1:17:52

       Yeah, I think it was all-cause mortal-

    6. AHAndrew Huberman1:17:53

       ... or just make bad decisions about anything in life, relationships and health-

    7. MWMatt Walker1:17:56

       Yeah, oh-

    8. AHAndrew Huberman1:17:56

       ... which can also be life-threatening.

    9. MWMatt Walker1:17:58

       (laughs) Yeah, I've tried to lean into that and claim that I, um, with those bad relationship situations that, "Oh, I just didn't have enough REM sleep last night, my darling."

    10. AHAndrew Huberman1:18:05

        Blame REM sleep. The REM sleep defense.

    11. MWMatt Walker1:18:07

        You know? Yeah. And, uh, but, uh, she's far wiser than, than I thought. But, um, so they've did this great machine learning analysis, and I may get these numbers backwards, but I think for every 5% reduction in REM sleep, there was a 13% associated increased risk of mortality.

    12. AHAndrew Huberman1:18:28

        Wow.

    13. MWMatt Walker1:18:29

        Uh, and I could have, I'll have to go back and, and check. But to me, the, and in the machine learning algorithm, what they ultimately spat out was that of all of the sleep stages, REM sleep is the most predictive of your longevity, of your lifespan. So we often, I hear people saying, "How can I get more deep sleep?" Uh, or they sometimes say, "How can I get more dream sleep?" And m- my answer is a question. "Why do you want to get more of that?" And they'll say, "Well, isn't that the good stuff?" And I'll say, "Well, actually all stages of, of sleep are-"

    14. AHAndrew Huberman1:19:00

        It's all the good stuff.

    15. MWMatt Walker1:19:02

        Yeah.

    16. AHAndrew Huberman1:19:02

        Well, it's like the exercise question, and it took decades for people to understand that moving around at, uh, for about 150, probably 180 minutes a week at doing endurance type work, zone two cardio type work, is, is correlated with living longer, feeling better, less diabetes, et cetera. There's really no way around it.

    17. MWMatt Walker1:19:24

        Yeah.

    18. AHAndrew Huberman1:19:24

        I mean, you can, um, you can ingest Metformin until the cows come home.

    19. MWMatt Walker1:19:29

        (laughs)

    20. AHAndrew Huberman1:19:29

        You can take NMN, all of which I think have, have their place in, um, certain contexts. I'm a big fan of the work surrounding all, all those protocols.

    21. MWMatt Walker1:19:36

        Yeah, likewise.

    22. AHAndrew Huberman1:19:37

        But without getting proper amounts of movement-... meaning sufficient numbers of, doesn't matter how many 12-minute exercise regimes you follow per week, you need that threshold level. And it sounds like the same is true of REM sleep and to- and total amount of sleep.

    23. MWMatt Walker1:19:54

        Yeah.

    24. AHAndrew Huberman1:19:54

        There's just, y- you, um, you pay the piper somehow.

    25. MWMatt Walker1:19:58

        Yeah, the return on investment, I mean, to, to flip the coin, the return on investment is, is astronomical.

    26. AHAndrew Huberman1:20:03

        Mm-hmm.

    27. MWMatt Walker1:20:04

        You know, I think of sleep, it, it is the tide that moves, you know, that raises all of those health boats.

    28. AHAndrew Huberman1:20:11

        And the most fundamental layer of mental and physical health. Whenever people ask me, uh, even though I'm not a physician, they'll ask me, you know, "What, what should I, what should I take?" Or, "What should I do?"

    29. MWMatt Walker1:20:19

        Right.

    30. AHAndrew Huberman1:20:19

        The first question is always, "How's your sleep?"

Episode duration: 3:06:05