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Speaker A: Welcome to the Huberman Lab guest series, where I and an expert guest 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 marks the second episode in our six episode series all about sleep with our expert guest, Doctor Matthew Walker. During today's episode, we discuss the do's and the do nots of sleep, focusing for instance, on how to use light and absence of light as well as temperature, both of your sleep environment, specifically the room you're in, your body temperature, and much more in order to regulate the timing and quality of your sleep. And we discuss how things like alcohol, caffeine and cannabis impact sleep and the various stages of sleep. And we discuss the various tools that exist now and that are rapidly becoming available to improve your sleep. This episode is essential for anyone trying to optimize their sleep. And when I say optimize your sleep, I mean trying to optimize the formula that was addressed in the first episode of the series, which is the QQRT formula. The quality, quantity, regularity, and timing of your sleep. Four variables that combine to determine whether or not your sleep is optimized for you and thereby providing the most restoration and improvement to your mental health, physical health and performance before we begin, I'd like to emphasize 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 Helix Sleep. Helix Sleep makes mattresses and pillows that are customized to your unique sleep needs. It's abundantly clear that sleep is the foundation of mental health, physical health and performance. When we're getting enough quality sleep, everything in life goes so much better. And when we are not getting enough quality sleep, everything in life is that much more challenging. One of the key things to getting a great night's sleep is to have the appropriate mattress. Everyone, however, has slightly different needs in terms of what would be the optimal mattress for them. Helix understands that people have unique sleep needs, and they've designed a brief two minute quiz that asks you questions like, do you sleep on your back, your side, or your stomach? Do you tend to run hot or cold during the night? Or maybe you don't know the answers to those questions. If you go to the helix site and take that brief quiz, they'll match you to a mattress that's optimal for you. For me, it turned out to be the dusk dusk mattress. It's not too hard, not too soft, and I sleep so much better on my helix mattress than on any other type of mattress I've used before. So if you're interested in upgrading your mattress, go to helixsleep.com huberman. Take their brief two minute sleep quiz and they'll match you to a customized mattress for you, and you'll get up to dollar 350 off any mattress order and two free pillows. Again, that's helixsleep.com Huberman to save up to dollar 350 off and two free pillows, today's episode is also brought to us by Whoop. Whoop is a fitness wearable device that tracks your daily activity and sleep, but also goes beyond that by providing real time feedback on how to adjust your training and sleep schedule to perform better. I've been working with Whoop on their scientific advisory council to try and help advance Whoop's mission of unlocking human performance. As a Whoop user, I've experienced the health benefits of their technology firsthand for sleep tracking, for monitoring other features of my physiology, and for giving me a lot of feedback about metrics within my brain and body that tell me how hard I should train or not train, and basically point to the things that I'm doing correctly and incorrectly in my daily life that I can adjust using protocols, some of which are actually within the Whoop app. Given that many of us have goals such as improving our sleep, building better habits, or just focusing more on our overall health, Whoop is one of the tools that can really help you get personalized data, recommendations and coaching toward your overall health. If you're interested in trying Whoop, you can go to join dot whoop.com huberman today to get your first month free again. That's join dot whoop.com huberman. Today's episode is also brought to us by waking up. Waking up is a meditation app that has hundreds of different meditations, as well as scripts for yoga, nidra and non sleep, deep rest, or NSDR protocols. By now, there's an abundance of data showing that even short daily meditations can greatly improve our mood, reduce anxiety, improve our ability to focus, and can improve our memory. And while there are many different forms of meditation, most people find it difficult to find and stick to a meditation practice in a way that is most beneficial for them. The waking up app makes it extremely easy to learn how to meditate and to carry out your daily meditation practice in a way that's going to be most effective and efficient for you. It includes a variety of different types of meditations of different duration, as well as things like yoga nidra, which place the brain and body into a sort of pseudo sleep that allows you to emerge feeling incredibly mentally refreshed. In fact, the science around yoga Nidra is really impressive, showing that after a yoga nidra session, levels of dopamine in certain areas of the brain are enhanced by up to 60%, which places the brain and body into a state of enhanced readiness for mental work and for physical work. Another thing I really like about the waking up app is that it provides a 30 day introduction course. So for those of you that have not meditated before or getting back to a meditation practice, that's fantastic. Or if you're somebody who's already a skilled and regular meditator, waking up has more advanced meditations and yoga knee jerk sessions for you as well. If you'd like to try the waking up app, you can go to wakingup.com huberman and access a free 30 day trial. Again, that's wakingup.com huberman. And now for my conversation with Doctor Matthew Walker. Professor Matt Walker, welcome back. We're all so happy to have you here. And in episode one, you beautifully described the biology of sleep. Why sleep is important. What happens when we don't get enough sleep? And you incentivized getting adequate amounts of great sleep. And you defined what great sleep is. And you provided some excellent practical protocols and tools for getting great sleep. However, today you're going to tell us, I believe, about the protocols for really optimizing one's sleep. Both conventional tools and protocols and some, let's say, unconventional, not heretical, but unconventional tools for optimizing one's sleep. So let's start with the basics. What are the basics of what I think I've heard you refer to previously as sleep hygiene?

Speaker B: Yeah, I think we, many of us can resonate with the idea of dental hygiene. Turns out there's something called sleep hygiene. And there are probably, I would say, five edicts of sleep hygiene. I offer them as tools and not necessarily rules because I don't think people respond to rules. People respond to reasons and not rules. So if it's okay, I'll probably just unpack each one of them rather than just sort of bark them at you and hope people assume that it's the right answer. I'll explain the answer so people understand why it's important. So as I said, there are probably five things that you can start doing tonight to try to improve your sleep. The first we've spoken a little bit about in that first episode. It's part of the four macros of good sleep. First piece of advice, regularity. Go to bed at the same time and wake up at the same time. No matter whether it's the weekday or the weekend, regularity is king. And the reason is because when you feed your brain the signals of timed regularity for your sleep, it will anchor your sleep and improve the quantity and the quality of that sleep. Because part of that signal of regularity going into your brain in terms of that repeated behavior night after night sleep, in other words, helps train that central 24 hours circadian clock that we also spoke about in the first episode. So that's the first piece of advice. Try to keep it as regular as you possibly can. The second piece of advice is darkness. In my view, we are a dark deprived society in this modern era, and we need darkness at night as well. You've spoken about to release a hormone called melatonin. And melatonin will help time the regular onset of your sleep. So that sounds great, but what boots on the ground, Matt, what does that mean? I would suggest the in the last hour before bed, try to dim down 50%, if not more, of your lights in your home, and you will be quite surprised at how sleepy and soporific that will make you feel. I will do this in a regimented way. I have a little reminder that pops up and tells me now is the time to dim the lights based on your bedtime. And I'll go around and I'll shut lights down in my bedroom. I will actually have a small light bulb, and it is way down to probably as little as maybe five Lux. And Lux is just a metric of the light. It's way down there and it's also very deep orange, sort of red. And we can come onto why that's the case. So that's the first thing, even before you're thinking about sleep, start to decrease the light. For example, if you were there, let's say, for a standard sleep schedule, at 10:00 p.m. and normally you are getting into bed at 10:30 p.m. but you feel pretty wide awake. If there was an electrical blackout and you lost your phone, magnetic, too. Phone goes down, lights go down, total blackout. My suspicion is that fairly soon you'd say, gosh, I actually feel quite sleepy. Whereas if the lights were blazing, you've got your phone, televisions on, lots of stimulation, you're probably going to think 1030 no, I could. I could probably push through for at least another hour. So try to dissipate that light and then if you need to wear an eye mask, blackout curtains always good as well. But we need that darkness at night because when you give the brain the signal of darkness, it releases, effectively, a brake pedal. That brake pedal has normally been applied by way of light on the release of that spigot of melatonin. And when you take the brake pedal off, it starts pumping out into the brain. You can also then, of course, probably reverse engineer this trick in the morning. And this is another component of why you've been, I think so, such a wonderful advocate for light in the morning. It does many things, but one of the things that it does is reapply that break on melatonin and therefore you lose the signal to your brain of darkness. That's what melatonin, in some ways is doing. We often call it the hormone of darkness, or the vampire hormone, not necessarily because it makes you look longingly at people's necklines and want to bite in, which is great if you're into that, but it's really simply about it's releasing melatonin, which tells the brain, my goodness, it's nighttime, but if you've got bright light on, you come from your office, you're driving home, so you've got artificial light during the day, which is probably not strong enough to stimulate you and bring you awake. You come home and you've got, again, bright light, but it's still strong enough now to prevent the release of melatonin. You start to shift in your timing and you may have problems with your sleep. So that's the second piece of advice I would love to ask you about that morning light two and the alertness benefits. I'm, as a sleep researcher, more focused on the evening component of light and decreasing it. But you've done a great job. I don't know if there's anything.

Speaker A: Yeah, there are a couple of quick points that are based on some what I consider really nice studies. There's beautiful work in humans showing that bright light exposure in the morning, especially from sunlight. But if one doesn't have access to sunlight for whatever reason, there are commercially available so called sad lamp, seasonal effective disorder lamps. They range anywhere from 5000 to 10,000 lux, very bright. But certainly morning sunlight viewing and lamps of the sort I just described have been shown to increase the amplitude of the morning cortisol spike by as much as 50%. 50. So people hear cortisol and they freak out. They think that's not good. I want my cortisol low. But you actually want your cortisol highest in the morning and lower in the afternoon and evening. And there's a lot of reason for that. Elevated mood, focused and alertness in the morning and throughout the day, ease of getting to sleep at night, lower anxiety, lower depressive symptoms, and so on. So that bright light also serves to control the amplitude of cortisol in the direction you want in the early part of the day. The other thing, that's just more of a underlying dynamics of the circadian visual system, which is a system that I worked on for years. These wonderful cells in the eyes that are not for image forming, but rather for detecting sunlight and bright light for sake of setting circadian rhythm, is that the sensitivity of that system early in the day is actually quite low. So you need a lot of bright light early in the day to effectively wake up your system and shut down the sleepiness signals such as melatonin. But later in the day, it's a rather diabolical system. It takes very little light, even from artificial sources, to disrupt your circadian rhythm and quash melatonin as little as 15 seconds of bright light in the evening. I think just Chuck Zeisser's laboratory at Harvard Medical School showed can quash melatonin in the evening. Now, I don't want people to freak out and think that they go into a hotel bathroom, which oftentimes those are very bright in the middle of the night, flip on the light, that they're going to completely screw up their circadian rhythms. But if I'm honest, they'd be much better off using their phone as a flashlight to navigate. People always say, well, wait, but the flashlight on the phone is very bright. But let's just get logical here. A light shown into your eyes, such as a flashlight, is very different than looking at a flashlight beam on the ground, far and away difference. So the point is that if you don't get enough bright sunlight or light in your eyes early in the day, and then you're indoors under artificial lighting, you might think, well, this is really bright lighting. This is the kind of lighting that could disrupt my circadian rhythm at night, and therefore it's sufficient to wake up my system. No, early in the day and throughout the day, you need a lot of bright light as much as safely possible to avoid sunburn and things of that sort, which you don't want. But then as the evening comes around after sundown, you need very little artificial light in order to disrupt your circadian rhythm. And then just very quickly, light from candles, fireplaces is okay. This is kind of interesting. It seems bright, but the measurements indicate that that's not going to shift your circadian rhythm much. Candles are great, but, of course, don't burn your house down. So the orange and red tones in the evening way dim down. That's the way to go. Early in the day, bright, bright, bright light. As bright as you safely can tolerate.

Speaker B: And what I like about, firstly, your mention of cortisol. You described how cortisol is rising in the morning, and that's a great thing, and it is a good thing. And in the evening, it's starting to drop. And if you look right around your prototypical bedtime, and we're going to speak later in this episode as to what your real natural bedtime is versus the one that you may be taking right now, it's very interesting. Cortisol will almost hit its lowest point, something that we call its nadir. It's the lowest point in that trough of its decline, right around the time when you should be sleeping. However, there's a great study that looked at people with insomnia, and in subsequent episodes, we'll discuss this, too. But one of the ways that we think about or conceptualize insomnia is in two different flavors. Sleep onset insomnia, I can't fall asleep, and sleep maintenance insomnia, I wake up and I can't get back to sleep. And what they looked at was essentially cortisol levels. They had a catheter in the arm, and they were sampling it from the bloodstream, and they were able to do that every 30 minutes. So it's a little bit like time lapse photography, and you're getting a data point every 30 minutes across the 24 hours period. Looking at cortisol across now a full 24 hours period. And sure enough, when you look at healthy controls, who can sleep well, and insomnia patients, they look almost identical across the day. But then when it comes to falling asleep, right around that bedtime period, the healthy controls are going all the way down. The insomnia patients go down and down and down, and then they have a rise back up right around that sleep onset period. And then they start to drop back down again, just as the control group. But then they also often will have a spike in the middle of the night, which then comes down, and then both of them are staying low throughout the early morning period, and then it starts to rise back up. So it's not as though net net overall, there is a higher level of cortisol in people with insomnia. It seems to be right at those trigger zones that map very nicely to sleep onset problems and sleep maintenance problems.

Speaker A: Very interesting. As somebody who wakes up in the middle of the night and sometimes has trouble getting back to sleep, that resonates. I have no trouble falling asleep whatsoever. Yeah, knock on wood. Superstitious about this at this point, but I use tools like non sleep, deep rest, yoga, nidra, long exhale breathing. But, you know, and I think these wake up episodes seem to happen more when I'm processing a lot of stuff from my daily life. That's right. The unconscious brain oftentimes is working through things and will wake us up.

Speaker B: Yeah, I often think that sleep maintenance insomnia that you've just described is the revenge of daytime emotions unresolved.

Speaker A: That's a great way to put it, yeah.

Speaker B: So that would be. So, we've spoken about regularity, we've spoken about darkness, and we've spoken about the inverse of that in the morning, which is light, a little bit of cortisol. So the third out of the five is going to be temperature. And the advice here is keep it cool, as we mentioned a little bit in the first episode. And we will go into great detail when we speak not just about these conventional and unconventional tips, but we're also going to go into the future of science and where sleep science is taking us to, in fact, optimize and even enhance our sleep. We will speak a lot about temperature. Suffice to say that you need to drop your core body temperature and your brain temperature by a little less than one degree celsius, two to three degrees fahrenheit to get to sleep and stay asleep. The general target that we have in sleep science, if you look across the literature, is somewhere around about the 67 degree fahrenheit, or I'm trying to do the calculation, maybe 18.5 ish degrees celsius. Now, I know that that sounds cold, and cold it is. But you can also wear thick socks to bed. You can have a hot water bottle at the end of the bed. That's great, too, but the ambient must be cold. The fourth piece of advice is walk it out. And here, what I mean is, do not stay in bed for long periods of time awake. And I think we mentioned this perhaps in the first episode, too, when you are awake in your bed for long stretches of time, because your brain is an incredibly associative device, it will quickly learn that this thing called my bed is the place where I'm awake and not asleep. And what you need to do is break that association. If you've learned that time and time again, because you've stayed in bed. And the rule of thumb, and it's just a, a rule of thumb, about 2025 minutes, if you can't fall back asleep or you can't fall asleep, it's okay. Just say, tonight is not my night. It's not a problem. Tomorrow is not completely shot. It's fine. I'm just going to get up, get out of bed if you can. If you're lucky enough, try to go to a different room and in dim light, read a book, listen to a podcast, whatever it is that relaxes you, just do that. Don't check email, don't eat, because if you start eating that again, trains your brain to start waking up and feeding at that time and only return to bed when you are sleepy and there is no time limit for that, I don't want you to come back after half an hour when you are still awake and not feeling sleepy enough. Why? Because you're going to get back into bed and be in the same problem again. And gradually, if you do this and it's hard to do it, you will relearn the association that you had, I'm sure, as a child, which is that your bed is this place of sleepiness. Because often people will be saying, I feel so tired in the evening. And then they get into bed and they say, but now I can't fall asleep at all. And I don't understand it. In part, it's because of that learned association. So that would be the fourth tip. The fifth tip makes me even more unpopular as a personality and character, which is, try to be mindful of your alcohol and caffeine. Now, in a subsequent episode, we'll go into great detail as to how caffeine works, its mechanisms, why it is sleep disruptive, and why, in fact, I've even perhaps changed my mind on caffeine and its benefits. But it also does have significant detriments to your sleep. So the rule of thumb here would be try to cut yourself off from caffeine probably at least ten or so hours before you expect to go to bed. And you can just calculate back, calculate that and try to limit it. So the dose and the timing make the poison cut yourself off after maybe two or three cups of coffee, and then that timing component, count yourself back, cut yourself off. Decaffeinated coffee, not too bad if you find the right thing to, if you need that fix. Alcohol is probably one of the most misunderstood sleep aids, in quotes, that there is. It is no sleep aid at all. Now, if I didn't understand what I know about alcohol and sleep, I would think that, too, which is, look, when I have a nightcap just before bed or two, even though I don't wear them, I may actually just fall asleep very easily. It feels like I stay asleep very soundly across the night. So it's a great sleep aid and it really helps me. There are at least, I would say, three issues with alcohol. The first is that alcohol is in a class of drugs that we call the sedatives. And sedation is not sleep. But when you take on board alcohol in the evening, you mistake the former for the latter, and you think it helps you fall asleep. The second thing is that because it's sedation. Well, actually, it's probably related to sedation. If I were to show you the electrical signature of your deep sleep when you're just sleeping naturally versus when you have alcohol in your system, it's not really the same. It's not a naturalistic form of deep sleep. It mimics it. It looks not too dissimilar. But if I really do my analyses, and I almost like that Pink Floyd album where I take the white light of electrical brain activity coming from your head as you're sleeping and split it apart into all of the different components, there are some components that are no longer present or some that are abnormally present. The second issue with alcohol is that it fragments your sleep, so it will litter your sleep with all these punctuated awakenings throughout the night. The danger there is that many of those awakenings with alcohol, you don't remember because they're too brief. But then you wake up the next day and you think, well, I didn't have a problem falling asleep. I didn't have a problem staying asleep. But I just. I feel rough. I just don't feel restored by my sleep. And you don't add two and two together. The final concern with alcohol is that it's quite a potent blocker of your rapid eye movement sleep or REM sleep. And in subsequent episodes, we'll go into great detail as to the incredible learning and memory creativity benefits that come by way of REM sleep. Also, it's essential for our emotional regulation and recalibrating our moods. So for all of those reasons, I would say two things. First, if you are struggling with sleep, not feeling restored by your sleep, keep in mind your alcohol intake. And also just in general, be mindful of that. If you are thinking about your sleep and want to preserve it.

Speaker A: So much of what you just said resonates. I confess that in my lifetime, I've had periods of pretty spectacular sleep. I characterize myself as somebody that could fall asleep anywhere, anytime. But I've also experienced the extreme challenges of sleep and that relates to different things, life circumstances, etcetera. In fact, recently I've had some challenges with sleep, despite using the protocols that I and others suggest. I hadn't heard some of the things that you're referring to here. And middle of the night waking has become more of an issue. I communicated this to a former girlfriend of mine who I was in relationship with when I was a junior professor, meaning before I got tenure. And she said, you don't remember? You had a Andrew. But I do. You had a pattern back then of after I would fall asleep, you would continue working on your laptop, probably on grants, and then I would fall asleep working. And then, according to her, I would wake up in the middle of the night and work a little bit until I'd get tired again and then fall asleep, and then this would repeat. So really stamping down the associative learning element that you talked about before. So that was probably the first period of time in my life in which I created this rather deleterious association of work in the middle of the night in bed. And then more recently, I've had the experience of waking up, probably due to these daytime things that I'm waking up in the middle of the night thinking about. And now, because of our discussion during the course of recording this series, I get out of bed after even 1015 minutes so that I can start to eliminate that association. And another piece is that I've always felt that when I get out of bed in the middle of the night because I can't sleep and I go to the sofa, I often can sleep very well. Provision being proving it's a control experiment, proving that the location of sleep and the association of wakefulness and sleep in bed, as opposed to on the sofa, is a clear component. And this is in an environment that's of equal temperature. I mean, it's not a perfect experiment, right. It's anecdote, as we say. But I think that the associative piece is oh so strong for many people. And so this is something to really take seriously.

Speaker B: I love that notion of. And people will often say, I just get up, I go to the couch or the sofa, and that's where I'll wake up in the morning. Also, they'll say, when I travel and I go to a hotel room, I just can sleep fine. Now, for some people, it's the inverse, but for those people, it's the contextual difference, meaning the change of the environment is so unfamiliar that it has not been bound to the association of wakefulness. It's related to sleep, or at least the opportunity to sleep. Sometimes even I've heard from some people, and there's no studies or data on this. Even turning yourself around now, this is hard if you have a partner in bed, but you just switch top to bottom of the bed, and you take your pillow and you pull the duvet all the way down and you put the pillow at the opposite end where your feet used to be. And you get into bed. And even just looking around and sort of having a different. That alone is so subtle, but it can make a real difference. So again, just keep these things in mind. I know it sounds strange, or this whole sort of get up, get out of bed, break the associate, and we'll come on to something. Well, actually, I'll come onto it now because I think it's one of the unconventional tips, and you mentioned it. A lot of people say to me, that all sounds great, the science makes sense. I just don't. It's dark, it's kind of cold. I really don't want to get out of bed. So give me some alternatives. I think the single best piece of unconventional sleep advice I can give you is do anything that gets your mind off itself. The principal reason that if you look at insomnia as a physiological condition or current working model mechanistically, of how insomnia plays out is that you are in this state of almost low level anxiety, and you are somewhat stressed. And when you go to sleep, or you try to go to sleep, or you wake back up and you try to get back to sleep, you just have this rolodex of anxiety. In the modern world, we are constantly on reception and very rarely do we do reflection. And unfortunately for many of us, and I've been guilty of this, the only time we do reflection is when our head is placed on the pillow and we turn the light out. And that is the last time you want to be doing reflection. That's the worst moment. And at that point, I think everyone can empathize with the idea of you turn the light out, you're under stress, your mind goes to those few things. In the darkness of night, thoughts become almost ten times worse than they do in the bright of day. And at that moment you start to ruminate. When you ruminate, you begin to catastrophize. And when you catastrophize, you're dead in the water for the next 2 hours. So what do you do? The problem is, as I said, your mind is on itself and it's going through these repeated loops. Anything you can do, for example, you can do some kind of a meditation. And I, when I was researching data for my book some years ago, I did look into meditation, and I wasn't a meditator, I was a hard nosed scientist. I didn't really kind of embrace with that notion or even that group of people, but time and again I read paper after paper and the data was very strong and it was coming from research groups that I respected very much indeed. So I thought, well, okay, I should probably give this a try. And that was six years ago. And since then, I now meditate for ten minutes every single night before bed. I do a guided meditation because I'm not particularly skilled, so I use an app that moves me through that. But you can do whatever you, whatever meditation you like. That's one example. The second example is you can do breathing methods because again, you're focused on your breath and what are you not focused on? Your thoughts. And so anything that will allow you to explore some other focus. Maybe it's a body scan where you start at the top of your head or you start at your feet and you work your way up and you just say, moving through. Now my neck. What sensations am I feeling now into my shoulders? Moving down into my chest. Now I can feel the ends of my fingers. Am I sensing anything? And when you start doing that or any of these types of things, the next thing that you remember is your alarm going off in the morning because you got your mind off itself. So I would say that that's probably one of the unconventional tips. But let me come back to the conventional. Anything else I've probably missed out or been unclear about there? Actually, I should probably say one thing in terms of these. They're not tips. I don't like the word. I know you don't either. Or hacks or. These are protocols, and they're well informed, scientific protocols. In all of this discussion today, you can get all of these things in place and still have problems with sleep. The reason is because you may be suffering from a sleep disorder. So the analogy would be, let's say that I'm your athletic coach and you're a sports superstar. I can perfect everything. I can perfect your diet, your supplements. We can perfect your technique, we can perfect. But if you've got a broken ankle, none of those things are going to alter your performance. Right now you've got to get to a doctor and get that seen to and then we can come back to fine tuning your performance. It's the same with sleep. If you've got a sleep disorder such as snoring, sleep apnea, or insomnia, we need to get you to a doctor first and then only after that come back. Once you're resolved, then we can start to optimize. That's the only other thing I probably should mention.

Speaker A: Yeah, this is all very useful discussion because I think that of course there will be those folks out there that just like what are they talking about? I sleep so well at night. Consider yourself blessed. Many, many people struggle with challenges with sleep. I think it's fair to say that sooner or later, most everybody experiences some challenges with sleep. For whatever reason.

Speaker B: Look at the statistics. That's highly likely in your lifetime, you are more than likely to go through either a period of challenging sleep or in fact a bout of insomnia.

Speaker A: I'd like to take a brief break and acknowledge our sponsor, ag one. Ag one is a vitamin mineral probiotic drink that also contains adaptogens and is designed to meet all of your foundational nutritional needs. By now im sure youve all heard me say that ive been taking ag one since 2012 and indeed that is true. Now of course, I do consume regular whole foods every day. I strive to get those foods mostly from unprocessed or minimally processed sources. However, I do find it hard to get enough servings of fruits and vegetables each day. So with ag one, I ensure that I get enough of the vitamins, minerals, prebiotic fiber and other things typically found in fruits or vegetables. And of course, I still make sure to eat fruits and vegetables and in that way provide a sort of insurance that I'm getting enough of what I need. In addition, the adaptogens and other micronutrients in ag one really help buffer against stress and ensure that the cells and organs and tissues of my body are getting the things they need. People often ask me that if they were going to take just one supplement, what that supplement should be, and I always answer ag one. If you'd like to try ag one, you can go to drinkag one.com huberman to claim a special offer, you'll get five free travel packs plus a year's supply of vitamin D. Three k two again, that's drinkag one.com. huberman you talked about alcohol. I'm not a consumer of alcohol anymore, nor am I.

Speaker B: And it's not because I have anything against it.

Speaker A: Yeah, many people do enjoy it, and we're not calling judgment on them. I mean, certainly much of the world enjoys alcohol. Could we talk a little bit more about, aside from demolishing REM sleep, do we know that alcohol causes these disruptions in sleep directly, meaning by changing the pattern of release of neurotransmitters like Gaba, things of that sort? Or is this an indirect effect? Is this through the gut microbiome that then impacts sleep? And the reason I ask is, maybe we could get to some more specific dos and do not protocols. So, for instance, if somebody wants to have a cocktail, how close to sleep can they get and not diminish their rapid eye movement? Sleep too much, because people are still going to want to drink. And with that said, if people do have a couple of drinks and then they go to sleep, is there anything they can do prior to sleep to try and rescue their I, some of their quality sleep?

Speaker B: Great question. So, in terms of the mechanism, it seems actually not to be the alcohol, but some of the metabolic byproducts of alcohol. We think that perhaps the main culprit may be some of the aldehydes that are the metabolic separate consequences of alcohol metabolism. You make a good point, though, in terms of the dose response timing curve. How late or how early do I have to cut myself off from alcohol? People have done those studies, and they have found that even an afternoon single glass of wine, if you measure sleep in the way that we measure it at my center, with high fidelity, you can see compromises and impairments. I wish I could tell you otherwise. I would say that based on that data, the principal protocol advice I would have for you is go to the pub in the morning. That way, by the time you're about to sleep, the alcohol is out your system. And you could. No, no, I would never, as a public scientist, I would never advocate, necessarily, for morning. I'm just kidding you. But that's sort of one of the unfortunate consequences. There does seem to be an impact. To say that there isn't is just me not being truthful about the data. But again, if you think about the trade off here, if you're going out or you're having friends over and you're going to make an incredible evening of memories, and you're going to open a favorite bottle of wine and have a couple of glasses of wine, is your sleep going to be compromised? Yes, it is. But maybe thats worth the trade. Off for that specific night. I would just not wish you to. And youve spoken a lot and so has our dear friend Peter Attir and others. There just doesnt seem to be any safe amount of alcohol. But I would say think about that trade off. Simply. However, dont make it a habit that youre doing it multiple nights a week or more. That would probably be the advice.

Speaker A: Great. What about food and sleep? How close to sleep is it okay to have a meal if you want to optimize your sleep? I like to eat my final meal somewhere around 06:30 p.m. and I go to sleep somewhere around 08:39 p.m. in an ideal world, sometimes I go to sleep a bit later, sometimes I eat a little bit later. It's just there's some variability with these. But put differently, what is the relationship between food intake and sleep quality in terms of timing of food intake? And then perhaps we can talk a little bit about food macronutrients.

Speaker B: It's very interesting. There was somewhat of a dogma out there that we have to stop eating three or 4 hours before bed for optimal sleep. If you look at the data, the data is quite a spread, no pun intended. There are some people for whom that works very well, and if they eat even 2 hours before bed, they just get disrupted in terms of their sleep. Some of that is about people just feeling too full and not feeling comfortable. Other aspects are that when you become recumbent, when you lie down, you have a higher risk of gastric reflux coming back up and therefore you get heartburn. And that's pretty miserable. And people will describe that too by way of close proximity of food intake relative to when you're falling asleep. Nevertheless, if you look at the data, and I did a recent very deep dive on this personally myself about twelve months ago, it's not quite as extreme as the dogma makes out. If you eat 2 hours before bed, on average, it doesn't seem to necessarily harm your sleep. Now that's very different than saying what is best to improve or enhance your sleep. But the way these studies were designed, it was looking at detriments. They then went to 90 minutes before sleep onset, and even there, there didn't seem to be market impairments. 60 minutes. You started to see maybe some signs, but on average the effect size was somewhat weak. But then when you get close to sort of 45 minutes or so, then things did start to deteriorate. I think it depends hugely on your chronotype and also just on your appetite, circadian rhythm preferences too. I am someone who I do not feel very hungry when I first wake up in the morning. I don't feel very hungry throughout most of the day. And I will onboard most of my calories, probably in the hours, probably in about a four hour period, maybe less even three hour period, and then I will cut myself off about 90 minutes before sleep. So classically I would have been considered as violating this sleep dogma of, of cutting yourself off at least 3 hours. I think it's very personal, though. Just experiment with it. You will know the situation. As for macros and specific food components, the data is a little bit mixed. Certainly what we know is that if you're eating a diet that is high in sugar and low in protein, your sleep is worse. Why would that be the case? Well, one of the reasons that we think is that if you onboard sugar, it can be somewhat metabolically active. And when it becomes metabolically active, it can increase your body temperature, your core body temperature, even just very subtly. But that's enough to disrupt your sleep, as we spoke about with temperature. But I think in terms of really the, what would be the ideal macronutrient and even micronutrient dietary recommendation that I would have for you. I don't think we have enough data yet above and beyond that statement.

Speaker A: Yeah, I've experienced when I eat a very low carbohydrate diet, which I've experimented with in the past, maybe even full ketogenic diet for brief periods of time, although I'm an omnivore, so I eat meat and eggs, and I also eat starches, pastas, rice, et cetera. But we know, based on beautiful work from, for example, Chris Palmer from Harvard Medical School, who is a guest on this podcast.

Speaker B: I listened to that. It was a great podcast.

Speaker A: Yeah. Chris is spectacular and has advocated the exploration of ketogenic diets for the treatment of various psychiatric conditions, not all, but psychiatric conditions. And he agreed with me on this, that when people go on very low starch, very low carbohydrate diets, that sometimes they can experience a bit of hypomania. Some people can and challenge this with sleep, and sometimes there are psychiatric reasons why people stay on those diets anyway. And then they have to do other things to encourage their sleep, either pharmacology or supplementation or some combination. But I can say anecdotally for myself, if I don't eat starches for an extended amount of time, a couple of days, I find it very hard to get quality sleep, as indicated by sleep trackers and just latency to fall asleep is longer than it is, etcetera. So I've opted to eat most of my carbohydrates later in the evening, which violates every rule of eat your carbs early in the day. And I think there are some data to support that. Eating carbohydrates early in the day may actually have certain benefits for weight maintenance or weight loss. I realize that, but those aren't my goals at the moment. Weight maintenance, yes. Weight loss, no. So I think I certainly feel after eating a dinner that has a bit more starch, pasta, rice, these things of that sort, and a little bit lower protein, as opposed to the inverse, like eating a couple of rib eye steaks and a salad, but no starch, that my sleep is substantially better. And I always attributed that to the relationship between some of these starches and the tryptophan serotonin Pavlov.

Speaker B: There is some data on that with the carbohydrate intake in the evening, and of course, that tryptophan and that carbohydrate intake will contain the precursor ingredients to something else that we've spoken about, which is melatonin. And so that may actually help healthily boost that melatonin signal. And there's a little bit of data on that to support it, too. We also did a study where we were looking at night to night to night sleep and carbohydrate intake the next day, and it did seem to support what you're describing in terms of some of the carbohydrate benefits. We also found a strange result that was almost the opposite prediction, that we made carbohydrate intake in the morning to equally help people wake up. And we were a little bit uncertain as to why. But we're going to go into more detail. The reason that you mentioned the suggestion of not take on carbs in the evening is in part based on the evidence that your body's ability to dispose of sugar. And obviously, when you're eating carbohydrate, you can have a higher spike of sugar. Now, that in part depends on what you're eating with that carbohydrate, and also, of course, the nature of that carbohydrate, whether it's simple or whether it's complex, whether it's simple sugars versus complex, more starchy carbohydrate. But the idea is that your body, even if you were to eat the same amount of carbohydrate in the morning, in the afternoon, or in the evening, same carbohydrate dose and type. But your body's ability to dispose of that without having excessive spikes of glucose is worse in the evening, better in the morning. That is, if you're concerned about your blood sugar and your metabolic health, maybe that's what you should do. I think that that data is unclear on the basis of, if you are glycemic normal, meaning that you currently do not have signs of type two diabetes, or you're not pre diabetic, then that may not necessarily be the case. And so I think that's why it could be beneficial for you. And I know that you think deeply about that, and I've even been tracking blood sugar as well. I don't have any signs of that, but I'm just fascinated by some of that data and how it interacts with my sleep, because I'm a sleep nerd. So I think right now, we just don't have plentiful data to recommend a particular sleep quote unquote diet for improved optimization. I would say, though, that we can be a little bit more relaxed about the timing of our food.

Speaker A: Earlier, you mentioned caffeine, and caffeine is a topic that we get into, into substantial depth in episode three. But there and now, I will emphasize that caffeine is the most commonly used drug worldwide. I think the statistic says that 90 plus percent of adults consume caffeinated beverages every day, which is remarkable. And a few years back, I recall there was an article in the Economist that charted the countries for which the caffeine consumption was highest, and way out on the peak, peak, peak of it's almost triple or quadruple what the second place country consumed each day was. Can you guess the country that consumes the most caffeine? Could be tea, coffee, any form.

Speaker B: I'm going to suggest it's a scandinavian country.

Speaker A: No, but they're up there. It was Switzerland. Now, I don't know if that's still the case, but apparently the Swiss.

Speaker B: The reason I went, I was thinking it was because I've seen the graph. I was thinking it was Sweden.

Speaker A: And if I have that wrong, certainly someone will put it in the comments on YouTube. Drink so much caffeine. They have a lot to think about. So. I love caffeine. I drink a black coffee, black espresso, and yerba monte. I love yerba monte. I've been drinking it since I was a little one because of the Argentines in my family. And I drink it in the early part of the day, typically a couple hours after waking or so. I'll have my first sip of caffeine and then I try to stop drinking caffeine somewhere around noon or 01:00 p.m. occasionally I'll have a shot or two of espresso in the early afternoon if there's important work to be done and I need to do that. But I've noticed that even that can alter my sleep in ways that I don't like. But the afternoon coffee for some reason tastes so much better than the morning coffee for me. I don't know what it is. So it's coffee yerba mate packed early into the day and a lot of it for me, I have a high tolerance for it, but then I let it taper. Is that an optimal contour of caffeine intake? Would zero caffeine be better? If someone's just really committed to sleep and they don't want to like caffeine, would zero be better than any? And what about that afternoon coffee or tea containing caffeine? I mean, how disruptive is it for sleep?

Speaker B: So the profile that you described, which is high peak early on, first thing when you wake up and then tapering off nicely down into the sort of early afternoon ideal, that sounds great to me. As for that afternoon coffee, it really depends again on when you are expecting to go to sleep. Now, for someone like you, I would say I would love to look at abstaining from that or just switching it out to if you're using these pods or however you're brewing it, let's just switch it out and do an experiment for two weeks and we will look to see how much is that afternoon coffee really impacting your sleep. And we'll track your sleep with some degree of high fidelity, with a wearable. And let's test that hypothesis because you go to sleep quite early, you are an early bird, maybe bordering on an extreme early bird. And we'll speak about, or we have spoken about those different flavors of chronotype. I would prefer you not to be having that caffeine in the afternoon based on how early you go to sleep. And I mention that preference because of what you described regarding your sleep maintenance insomnia. One of the issues with caffeine is that not only can it make it more difficult for you to fall asleep, which you don't have, in part because if you're waking up quite frequently throughout the night and struggling to get back to sleep, you're going to be carrying a sleep debt into every night. And that debt continues to grow and it's almost like compounding interest on alone. So you will not have a problem falling asleep. In fact, sometimes the speed with which people fall asleep and some of these sleep trackers will almost penalize you for falling asleep too quickly, is because in sleep science, in clinical sleep medicine, it should take you somewhere healthy. Sleep onset, five to 1520 minutes. But if you put your head on the pillow and you turn off the light and within a minute or so, you're dead to the world and you're gone, I'm exactly, I'm worried that you're a carrying asleep debt now. Not necessarily, but I would like to explore it with you. And then I would say, even if you can fall asleep, fine. This factor of waking up in the middle of the night is also related to caffeine. Why? Because caffeine not only can make it harder to fall asleep, not your problem, but it keeps you out of that deep, deep sleep, and it puts you into a more shallow state of non rapid eye movement sleep. And when you are in the shallow state, it's a easier for you to be woken up. But B and I think more of the problem, it's harder for you to fall back asleep because your brain doesn't necessarily want to go back down into that deep sleep, and nor has it come up out of that deep sleep. So you're not in that wonderful, glorious, thick, treacly sort of sleepy state. When you wake up, you go to the restroom, you come back and you just know, oh, this is going to be great. As long as I can fumble my way back to my mattress, I'm going to be asleep within another two minutes going back to it. Whereas for you, you probably wake up and you feel pretty wide awake. I would like to see what happens when we negate that afternoon coffee on the frequency and the duration of those middle of the night awakenings for you.

Speaker A: Yeah, I'm definitely making the effort to avoid caffeine intake in the afternoon, and I think already starting to see some of the positive benefits of doing that, as evidenced by the days that I consume caffeine in the afternoon and experience the deficits. It's a real thing. I believe you've about the numbers on a different podcast previously talk a little bit about the metabolism of caffeine and maybe even some of the variations that exist between people in terms of the metabolic regulation of caffeine. So how long, let's say, drink a standard cup of coffee or a couple espresso and it has a, gosh, I don't know, 150 milligrams of caffeine. Is that 200, 5200 let's say 200, because certainly, you know, a barista these days, it's going to draw a beverage.

Speaker B: It'S going to over index. Yeah.

Speaker A: So let's say 200 milligrams, and somebody consumes that after lunch at 01:00 p.m. and their bedtime is, let's make them more conventional than I. Somewhere between ten and 11:00 p.m. okay, so they're about nine to 10 hours out from their bedtime. They're having a nice strong, quote unquote, nice strong cup of coffee after lunche. What does that look like in terms of their biochemistry and impact on sleep?

Speaker B: So caffeine has something that we call a half life of about five to 6 hours, meaning that after five to 6 hours, about 50% of that caffeine is still circulating in your bloodstream and thus your brain. That means that caffeine has a quarter life of somewhere between ten to 12 hours. Now, this is on average, and we'll come back to variations, but think of it this way. If you're taking a cup of coffee like you described there at midday, and then you're going to bed at, let's say, eleven or midnight, that would be the equivalent, based on what I've just told you, the quarter life of getting yourself into bed. And just before you took yourself into bed, you swig a quarter of a cup of coffee and you hope for a good night of sleep, and the chances are that it may not happen. Now, again, that's a little bit of sort of hyperbolic as a statement, but just try to conceptualize it in that way. You would never think about taking on a last quarter cup of coffee just before you put your eye mask on.

Speaker A: No, but I have some friends and somebody actually, who works with the podcast team, and we'll go out to dinner as a team when we're on the road, and he'll order a big coffee right after 09:00 p.m. dinner. And I was like, can you sleep? And it's like, oh, yeah, no problem.

Speaker B: And that no problem is in part this. I don't have an issue with falling asleep, but if we were to, based on the data map their electrical brain activity, you would be able to see this reduction in the deep non rem sleep. And it can reduce it. If you look at the data, somewhere between 15% to 20% now. But for me to reduce your deep sleep by 15% to 20%, I would probably have to age you by about 20 to 22 years. Or you could just do it every night with a late night coffee, should you wish again. And maybe we'll speak about this in later episodes. I have changed my mind on caffeine. I think morning caffeine use, or coffee, I should say being more specific is fine, because I think there are health benefits and we can go into in subsequent episodes why coffee, and the coffee bean itself can provide those benefits. So I've become a little bit more bullish on morning caffeine, but evening caffeine, I just think the data is just not supportive, even if you are, and there are variations, and you are very astute in your question. Some people, I said, on average, caffeine has a half life of about five to 6 hours. For some people it's quicker, and for other people it's slower. Why is that? It's based on a gene, and we know the gene. It's a gene that is part of a set of liver enzymes. And the gene is called the Cyp one, a two gene. And there are variations in that gene, what we call polymorphisms. And you can do these genetic tests that you can buy these kits and they will probably tell you which you are. Are you sensitive? Are you not sensitive? You probably already know. And so some people will not be as sensitive. And therefore they can have a more compressed timeframe of a half life because it's moving out of their system in a quicker manner. So again, I'm not trying to be scurmongering. I think you can have coffee in the morning and you'll be just fine that late night coffee. I would like to see you obviate that if you are someone who's doing it.

Speaker A: And the afternoon coffee sounds like maybe only every once in a while and try and make it mostly decaf, or decaf for that matter. If it's really just for the taste.

Speaker B: Yeah, if it's just for the taste, go decaf. If it's not, I understand that in some ways what I'm talking about is the ideal world. And drum roll. It turns out that most of us don't live in that. We live in this thing called the real world. And so if you are facing a circumstance where if you're under pressure at work or if you're a high performing athlete, and this is it, this is the event, this is. It's all or nothing, understand that you are going to sacrifice some sleep at night, but maybe that sacrifice is well worth it. So again, I'm very open minded. I'm not trying to be simply, you know, too rigid with this.

Speaker A: I want to take a brief break and acknowledge our sponsor, Insidetracker. Insidetracker is a personalized nutrition platform that analyzes data from your blood and DNA to help you better understand your body and help you reach your health goals. Now, 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. The problem with a lot of blood tests out there, however, is that you get information back about metabolic factors, hormones, et cetera, but you don't know what to do with that information. With Insidetracker, they make it very easy to understand your results, and they also point you to specific directives that you can follow in the realm of nutrition, exercise, supplementation, even prescription drugs that can help bring the levels back into the ranges that are optimal for you. Insidetracker also offers Insidetracker Pro, which enables coaches and health professionals to provide premium and personalized services by leveraging Insidetracker's analysis and recommendations with their clients. If you'd like to try Insidetracker, you can go to insidetracker.com huberman to get 20% off any of Insidetracker's plans. Again, that's Insidetracker.com hubermandhenne so you've talked about alcohol and its effects on sleep. You've talked about caffeine and its effects on sleep. And we talked about food and its effects on sleep. What about THC and CBD, sometimes referred to more generally as cannabis. And it's interesting. Gosh, when I was growing up, cannabis was illegal. Nowadays it's either legal or tolerated or decriminalized in many places. Not all, but I would say there's been a tide shift in terms of cannabis, meaning that many people consume cannabis who are consuming it legally and consume it for a lot of reasons, that other people consume alcohol in a sedative effect, a slight hypnotic effect. The actual definition of what these drugs do goes by certain terms in the psychiatric literature, of course. But in order to, quote unquote, mellow out, to feel more relaxed, to reduce their anxiety, it's far and away different than when I was growing up where, I mean, you would get into a lot of trouble if you were caught smoking a joint or taking a bong rip in the middle of the day. And I realized most people aren't doing that at work. I guess it depends on where you work. But edibles, tinctures, I mean, the consumption of THC and CBD is quite robust in a lot of places. So with all the issues of legality and the fact that people who. Young people should not be consuming them, even people 18 and younger, not just for legal reasons, but the brain is still developing. What is the story with THC? CBD cannabis edible smoked tinctures on sleep.

Speaker B: Specifically, it's very interesting if you look firstly at the motivational reasons why people use cannabis, based on the published study, somewhere in the top two sleep.

Speaker A: To fall and stay asleep.

Speaker B: To fall asleep and stay asleep. Obviously, usually the principal first reason is just to get high and have the experience and the pleasure of being high, if that's what sort of floats you, floats your train. But certainly it's sleep and what we call a hypnotic, to put you asleep from the greek derivative of the God for sleep that is high. Among the reasons that people will use, we currently don't recommend it, and here is why. Certainly THC helps you fall asleep faster, very clear in the data. The problem is that first you start to develop a tolerance and to get that same sleep onset benefit, you need to get use, I should say, a higher dose. So you start to develop dependency and your dose regimen starts to increase. The second issue with THC is that it's very good at blocking your dream sleep, your REM sleep. In fact, many people, when they come and they tell me, look, I was a heavy cannabis user, or even a light cannabis user for some time, and then I stopped using and one of the strangest things happened to me. I just started to have the most wild, vivid, crazy dreams and I didn't know what was going on. And it's a very simple explanation. As you've been using, your brain has been compromised in the amount of REM sleep it's been getting, and you've been building up chronically a REM sleep debt. And your brain is smart in the sense that it does try to clock, to some degree a counter of how much REm sleep you've lost. And many people will say, yeah, I don't really remember my dreams when I'm using, but when they stop the brain finally, because it's been cleansed of the thing, that's the roadblock to REM sleep. Not only do they go back to having the normal amount of REM sleep that people would have, they have that, plus they have what we call a REM sleep rebound, which is even more and more intense REM sleep, which leads to more intense dreaming. So it's a very. I suspect there's a lot of people who've had that experience listening, if they have been users and they've stopped. So that's the second reason we don't advocate it. The third reason is that when you stop using, you also go through a very vicious insomnia withdrawal syndrome. Often many people will do. Now, that depends on how much you've been using, for how long you've been using. If you look at the data, and by the way, part of the clinical diagnostic, the psychiatric diagnostic description of cannabis withdrawal is insomnia. That's how reliable this insomnia problem is when you come off cannabis. And if you look at the data, one of the main reasons that people relapse and start using cannabis again, even though they don't want to, is because they can't deal with the insomnia that withdrawal has given them. So you don't want to get into that vicious cycle. Should you wish again, it's your choice. So THC, I think, is not to be advised right now. CBD is interesting. I don't think there's enough data yet for us to have a very strong opinion, but I can at least offer mine. The data so far is a little bit mixed in what we call the effect size. In other words, how reliable and how powerful is the benefit of CBD on sleep? But it does seem to have some benefit. What's interesting is that it doesn't seem to have the detriments that I just described. For THC, you've got to be looking at the data a little bit careful with CBD. It has what's called a u shaped function to it, which is that if you're taking too little, and again, I really am so mindful of not trying to be. Okay, here are the numbers, but if you look at them, I would say cross your eyes, squint your eyes, maybe less than 25 milligrams, you run into the danger of CBD being wake promoting rather than sleep promoting. But once you get past, if you look ish, 50 milligrams and above, then you start to go in the opposite direction where it seems to be sleep promoting. And I mention that just because at least here in the United States and in many places in the world, that industry is not regulated. So it may say 50 milligrams on the bottle, you don't really know how. Some of those companies will have what's called third party laboratory testing, where they'll send it out and you can scan a QRI code and you can look at an independent laboratory that tested it and show you the purity of it. So that may be one way to go. So CBD, I think, has some favorable evidence right now. If that's the case, let's just assume that you and I speak in another five years time, and there's really good data now for this. What could be the mechanisms? I think there's at least. There's probably at least two, maybe three mechanisms. The first is an indirect mechanism. CBD has been demonstrated very nicely in some fantastic studies to be an anxiolytic, which is a fancy term for saying it reduces down your anxiety. And earlier you and I discussed that anxiety and stress is one of the things that will keep you awake. So indirectly, it removes this kind of gate that is preventing you from moving down the royal road of sleep, and it opens back up the gate because it's removed that gait mechanism, which is high anxiety, and by way of being an anxiolytic, it softens that anxiety and it's easier for you to fall asleep. I think that's probably the principal mechanistic bet I would have right now. Another indirect mechanism. If you look at some of the studies in rats, and we do human work at my sleep center, so we don't do animal studies, but if you look at the data in the rats, CBD can be hypothermic, which means that it drops your core body temperature. And just as we spoke about earlier in this episode, you need to drop your body temperature to get to sleep. So I think that's the second reason. I think the third reason is that it could have a direct sleep promoting mechanism. I think it's unclear right now exactly how it's interacting with the sleep machinery of the brain. We've got some hypotheses. The danger is, again, it's just not a well regulated substance. So I am actually just. Full disclosure. I'm working with a company in the United Kingdom in collaboration with King's College and the Institute of Psychiatry there to see if we can create an analog, a clean analog of CBD. But I think the potential upside of it, not just for sleep, but for a number of different psychiatric conditions like anxiety, could be beneficial. So I would say that that's right now the. The skinny on THC and CBD.

Speaker A: Okay, so just to make sure that I have the basic list of sleep hygiene factors. Correct. I have regularity. Is king.

Speaker B: Yep.

Speaker A: Light and dark, meaning that one should optimize, or at least seek to optimize their exposure to light in the morning and throughout the day and then in the evening to make things dim and darken.

Speaker B: Yes.

Speaker A: Temperature. And there you have a little. It's not a mantra, but what is it? It's warm up to cool down to fall asleep, and then it's stay cool. Like Fonzie, stay cool to stay asleep and then warm up to wake up. Yep.

Speaker B: And we will come onto that, I think, in a little while again.

Speaker A: Then there's walk it out, which is, if I understand correctly, if you're trying to fall asleep or fall back asleep and it's taking you longer than about 2025 minutes, you should just get out of bed and go elsewhere in the house, do something else, maybe even lie down on a different surface in the house to try and see if you can sleep there. But don't stay in bed. Don't create a paired association of wakefulness and your bed because that can lead to problems in subsequent nights.

Speaker B: Yeah, and I would only say that try to resist if you can. If you really want your bedroom to be the place where you now become consistently asleep, try not to start sleeping in some other location consistently because then all of a sudden, you bond that with good sleep and you unbuckle this notion that we're trying to relearn, which is no, your bedroom is the place of sleep, so it's fine to go elsewhere. Try to stay awake and force yourself to stay awake until you are absolutely sleepy, then go back to bed.

Speaker A: Okay. And then we discussed alcohol, food, caffeine and THC CBD, aka cannabis. And with respect to alcohol, it's clear that none is best if you're going to have some. You don't want to drink too early in the day, but you don't want to drink too much or too close to bedtime because it can disrupt rapid eye movement. Sleep. Food seems that creating some sort of buffer between your last bite of food and your to bed time by anyway, somewhere between maybe two, 3 hours. But for some people it'll be more like 90 minutes. And of course that's going to depend on the size of the meal, etcetera. Eating a big meal and then going straight to bed, probably not a good idea. Caffeine has this long half life, so if you're going to indulge, which I do do so early in the day, beware the afternoon caffeine.

Speaker B: Yeah, do the Huberman taper is what I'm going to call it right now, which is not an interpretive dance, it's.

Speaker A: Simply the caffeine taper and then THC. CBD does nothing good for your sleep architecture, although some people have the impression that it is good for their sleep because it makes it easier for them to fall asleep, but what they are unaware of is that it is disrupting the quality and architecture of the different stages of sleep in ways that are not serving people well.

Speaker B: That seems to be the case for THC, and I think CBD has promise and research must try harder, including my own.

Speaker A: And you very kindly emphasize that you're not telling people what to do. They just should know what they're doing so that they can make changes if they so choose.

Speaker B: That's right. I would always say that I'm not trained to be a medical doctor. Any advice that I give is simply scientifically descriptive advice. It's not medically prescriptive nor lifestyle prescriptive advice.

Speaker A: I'm smiling because what I always say is I'm a scientist, not a physician, so I don't prescribe anything, but I profess lots of things. Whereas my good friend who's a musician, Tim Armstrong, says, I'm not a cop.

Speaker B: That's right.

Speaker A: So do what you want. Okay. What a wonderful list to leap off into the unconventional and more advanced tools for sleep enhancement. So let's go there.

Speaker B: So I think many people may have heard of some of the conventional, but what about the unconventional? I would probably offer five or six. The first one I would say is that if you are struggling with sleep and you have had a bad night of sleep, the first recommendation is do nothing. And what I mean by that is if you've had a bad night of sleep, you're awake for 3 hours. Do not sleep in any later into the morning, do not go to bed any earlier, do not increase your caffeine intake to try to offset it, and do not nap during the day. Why am I telling you those things? If you wake up later that following morning, your adenosine clock that we spoke about, this building up of sleepiness that happens when we wake up is going to start later in the day. So when it comes time for you to fall asleep at what would then be the next night at your normal time, you're not going to feel as sleepy. Why? Because you woke up that much later and you're setting yourself up for failure again. Equally, don't go to bed any earlier. If you have become accustomed and your brain has and your circadian clock has become accustomed to going to bed at a certain time, and hopefully you're doing it regularly, then getting into bed two or 3 hours early has the danger. It's not a certainty, but a danger of you then getting into bed and thinking, well, I know I had a bad night of sleep last night, but I still can't fall asleep straight away. So now you're spending another 90 minutes in bed at the beginning because you've gone to bed 90 minutes earlier thinking it's a good idea to compensate. Don't do that either. Hold out even if you do feel tired. My recommendation would be, after that bad night of sleep, hold out for as long as you can, as close to your natural bedtime as possible. Then go to sleep and you will give yourself highest chance of success. Don't over caffeinate. That's the obvious one. Follow the beautiful huberman taper and then obviously try not to compensate with a nap. Why? Because that nap, as happens when we sleep, is going to remove some of that sleepiness, that adenosine. And once again, you get into bed and you're not as sleepy as you would naturally be. So you again go through a bad night because you're struggling to sleep or you wake up and you can't get back because you've got less weight of sleepiness on your shoulders due to the nap that happened earlier. So I know it's hard, but I would say when the alarm goes off after a bad night, you just think, I do not want to get up. It's been such a rough night. I know it's a short term gain, but trust me, it's a long term loss because you're going to then just get into this vicious cycle. So that's the first unconventional tip.

Speaker A: Can I just pause you for a second? I'm a little wide eyed over here because I did not know any of that. Typically, if I get a poor night's sleep, I'll do whatever I can to recover that sleep. Take a nap. I'll adjust my to bedtime the next evening. So I hope everyone is paying careful attention to what Matt just said. That's an important list because I think one of the very common things is for people to just not get a great night's sleep. And I think most people think, okay, I'll drink a little more caffeine, I will go to bed a little earlier tonight, maybe catch a nap in the afternoon, this kind of thing.

Speaker B: And I would have thought that too, and maybe even suggested that. And if you listen to the first episode and where we I list in a doomsday manner the things that can happen by way of a short night, you would think that that's what I would then recommend. But it was really imprinted on me by a wonderful sleep clinician, Michael Perlis, who sort of described some of these features and exactly the reasons underlying them. And I think I've just tried to bake that out into a formula that makes sense. Again, it's not about the rule, it's about explaining it, because when you explain it, at first it sounds contradictory and paradoxical. When you understand it, it hopefully sounds logical and actionable. So that would be the first suggestion.

Speaker A: Could I just interrupt again? My audience hates when I interrupt, but I'm doing it on their behalf. I love it because I like to think that there's some value in at least what you say. In response, I saw a really terrific post from Doctor Rhonda Patrick, who we both know and admire for her public health education work. And she described a study whereby if people are, I think it was slightly sleep deprived, maybe by a few hours, that some of the disruption to morning blood glucose regulation that is known to accompany partial sleep deprivation and certainly complete sleep deprivation. But in this case, partial sleep deprivation could be offset by still exercising in the morning. That's right. Which frankly, I have to say if I haven't slept that well, then normally I'm. Maybe today's the day I don't exercise. But now having heard that information, I make it a point to still exercise, sometimes with a little bit less intensity, because I don't want to be completely exhausted in the afternoon and go to sleep at 04:00 p.m. or something really disrupt my schedule. But I thought that was really interesting because it's a sort of partial inoculation of the blood glucose disruption caused by sleep deprivation.

Speaker B: I'm so glad you brought it up. It's a fantastic study and Rhonda and I think even tried to discuss it some years ago on a show. But I like it because it does offer some degree of actionable hope and a strategy. Blood sugar, absolutely critical. It is very sensitive to sleep. When you don't get enough, it goes in bad directions. You used a very specific word, cleverly so. And that word was partially at first. You hear or read that study, and Rhonda was never suggesting this too. I'm not saying that you think, well, if it offsets blood sugar, and the study was saying exercise can nullify a lack of sleep. You conflate that single outcome benefit with the idea that, well, but maybe it doesnt actually compensate for the deficits in immune function or cardiovascular disease concerns or my hormonal health or my learning and memory or my emotional and brain health. Maybe it does, but maybe it doesnt. So I think I would always just caution people to saying when you hear a study like that, it's very natural to think, oh, that must mean that it translates to everything else in my body and everything else in my brain. It may, but it also may not be terrific.

Speaker A: So if you don't sleep that well, do your best to still get some exercise. But just be mindful of the fact that in the winter months, especially if you go too hard in the gym or on a run, you might be a little bit immune compromised. Just be mindful of the fact that you're a more vulnerable being when you're sleep deprived. But that exercise can help adjust things in the right direction. And if it's early in the day, presumably that's not going to disrupt the proper bedtime. And if it's later in the day, I suppose as long as you don't need caffeine in order to do that exercise and or if you're familiar with exercising later in the day, fine. I find if I exercise, I'm not one of these people thinking, go for a run at 07:00 at night and then just shower because you're a morning type. Because I'm a morning type, other people can, okay, we'll get into exercise a bit more in a later episode. We should do. We'll be sure to do that, but nonetheless, just raise that now. So what are some of the other unconventional protocols for sleep?

Speaker B: So I think other suggestions I would have after do nothing would be try to think about limiting your time in bed if you are struggling with sleep. This is something that is used in probably the most well validated psychological intervention for insomnia and it's called cognitive behavioral therapy for insomnia, or CBTI for short. What happens is that you work with a clinician, they interview you, they assess all of the reasons that you may not be sleeping, and then they create from their toolbox of many different options a bespoke, tailored, sort of Savile row soup prescription for you for your treatment. If you look at the studies of that collection of different tools in the CBTI box for intervention of insomnia and you ask of all of those which seems to carry the greatest impact on insomnia, which has the greatest sort of gravitas, it seems to be this thing that we call bedtime rescheduling. It used to be known as sleep restriction therapy. But obviously if you come to me and you say, look, I'm not sleeping very well, I've got insomnia, I say, I understand and I've got a treatment for you, it's called sleep restriction therapy. And you say, no, no, no, you didn't understand, I'm not getting enough sleep. But it's not quite that. Here's how it works. If you are spending so much time in bed, too much time in bed, you are not forcing your brain to be efficient and by way of constraining your sleep window even to, let's say, 5 hours a night to begin with, I brute force ruthless efficiency from your sleeping brain after several days. So another analogy would be let's say you're trying to make a nice thin crust of, of pizza base and you put the dough on the table and you start rolling it out. If you roll it too thin, it starts to get gaps and holes in it. Why? Because you've spread it out too far and you've started to create these absences. That's the same thing that happens. And it's very natural. As an insomnia patient, you would say, I'm just not getting enough sleep, so I'm going to start spending more time in bed. It's the very worst idea. Another way would be to say, look, I go to the gym and I spend about an hour and a half working out, but if I were to videotape you, a lot of people are doing the, I think I've coined it as your phrase, but the 11th rep, where people do the ten reps and then all of a sudden there's the selfie or there's the social media.

Speaker A: Oh, yeah, the texting, they finished the last rep, put it down straight away.

Speaker B: And if you look, they're only working out for about, let's say 45 minutes and the other is wasted. So what if the next day you came to the gym and I said, look, I'm sorry, and there's some big bouncer guys at the door, you are only allowed to work out for 40 minutes, and then we're going to eject you. And the first day you go back and you do the same thing, and then you've only got through 30% of your workout. So you get booted the next day you come back and you do a little bit more and you get booted again. After about five or six days. You've built up such a strong desire and hunger to get your workout in. You walk in, you put your phone on silent, you put it over in the corner and you just get to it. And that's the same thing that we're trying to do with sleep restriction therapy. So you have to be a little bit careful. Do it under supervision, especially if you're driving or you're operating heavy machinery. We just want to keep an eye. It's not necessarily a big concern, but we would say, okay, andrew, you're currently spending almost total about eight ish or seven and a half hours in bed tonight. I'm going to restrict you down to 5 hours a night and we're going to do this for the next week. And the way that we normally do it is I don't change your wake up time, I change your to bed time. Why? It's easier to stay awake longer than it is to wake up earlier. So I put it on the front end to the compromise and at first things don't change. But after maybe about four or five days of going through this, I build up enough of a short term debt in your system that your system all of a sudden thinks, gosh, I just cannot be as lazy anymore. I can't do this thing of waking up in the middle of the night and spending an hour and a half awake. I don't have the choice anymore. There's so much physiological buildup and pressure to do this. And gradually what happens is that you sleep longer, you don't wake up as much, and after maybe about two weeks of doing this, all of a sudden you go to bed at this later time. So for you, let's say you normally go to bed at eight, I'm going to have you go to bed at maybe ten 3011. But we're still going to have you wake up at that sort of 04:30 a.m. mark that you would normally wake up and all of a sudden you go to bed at ten 3011, you're out like a light. And then again the next thing you remember is your alarm going off saying I'm sorry, you've got to wake up. And what happens by way of that reset is gradually we will then once you're stable we will start to back it off. We'll start to have you go to bed at ten and if it stays stable then 945, then 930 and titrate you back to where you were. And if there's any sign that you're starting to not sleep well, we zip it back up again. The goal here is in some ways almost like hitting the reset button on your wifi router. I'm trying to retrain your brain to better sleep because when you are not sleeping well, you've lost your confidence in your ability to sleep. And when I do this technique with you gradually your system and you cognitively relearn that you are a good sleeper and you can trust in sleep. And now your sleep does not control you. You control your sleep. The hard part, however, is that it's not easy to go through. And we have to usually ask two questions with individuals. Firstly, what is your motivation for better sleep? We need to know that you really are motivated. And then second, you just stay with a high touch, white glove frequency, checking in on individuals and motivating them to keep going because it's very easy to fall off the wagon. So that's the next suggestion. Sleep restriction therapy or bedtime rescheduling, as we would call it.

Speaker A: You said it's difficult for people to go through. It takes a little bit of rigor, a little bit of attention means in some cases getting less sleep than one would like. But as compared to something that sadly, I've experienced a lot in my life of having challenges with sleep and trying to get things back in order and looking at the bed and just going, oh yeah, battleground, battleground. I think it makes a lot of sense. And I love the analogy to the gym. Somehow if there's a restriction to 1 hour in and out the door or maybe 70 minutes in and out the door because you need to put your stuff in a locker or something like that, it always, at least for me, gets done best when you just have those constraints. I think there's something about the human brain that we don't do well in unrestrained systems that I really think guardrails are fantastic. I love deadlines, for instance.

Speaker B: Yeah.

Speaker A: Discipline is essentially the hard deadlines, or as they say in academia, because we write grants all the time, drop deadlines, which, who made up that term? But if you don't make it, that's it. There isn't a, hey, I'll send this in tomorrow, PM Pacific time. That website closes and you better get.

Speaker B: Things done all of a sudden. It's surprising how much distraction you can pull out the noise and focus on the signal. It's great. Signal to noise ratio. Yeah.

Speaker A: And I love the idea that one can control their sleep as opposed to sleep controlling them. I think that that's and this notion of sleep confidence, one's confidence in their ability to sleep. These are important terms and they're more than just terms because I think that a field and an area of health practice and gosh, what's more important than sleep? It's the foundation of mental health, physical health and performance. Period really thrives on a common nomenclature. And I really appreciate that you're peppering these episodes with new nomenclature that captures a lot of the essence of the protocols and the mechanisms. So there. That's my editorial. Please continue.

Speaker B: I would say that in terms of other things, maybe just to go through them a little more quickly, we've spoken some about a wind down routine. Most people underappreciate the importance of a wind down routine. We often think that sleep is like a light bulb, that we dive into bed, we switch off the light bulb, and sleep should appear just as quickly. It's untrue. Sleep, in terms of a process, is much more physiologically like trying to land a plane. It just takes time to come down onto the terra firma of good sleep at night. Whatever it is you enjoy as a relaxation method, engage in it. Could be listening to a podcast, could be reading a book. Maybe it's a meditation, it's light stretching. Maybe whatever it is that you do, just build it into your regimen. You would never be driving down the road and then pull into your garage at the same 40 miles an hour speed. You gradually decelerate and you come to a stop. It's the same thing with sleep. So you need to find some way to decelerate. And we've spoken about methods already as to how to do that. The next tip is a little quirky and funny. Do not count sheep. There's a great study from my colleague, doctor Alison Harvey at UC Berkeley, and she put this to the test. Didn't make people fall asleep faster, it made them take longer to fall asleep. However, she did find an alternative. If you are not into meditation or podcasts or sleep stories or whatever it is that you wish for, try taking yourself on a mental walk. And it has to be a walk that you know very well. So let's say that you walk your dog every day, and you know, there's a couple of walks that you take with your dog. Do it in hyper detail. So close your eyes. You go to the front door, you clip in the dog to the leash, you walk out, you go down the steps, out to the driveway. Then you take a right, but you always cross over, and you look to the left and the right, because that's the place where traffic always comes. You cross over, and now you're walking up, and there's that strange sort of set of garbage that's been outside of that house for a long time, and you don't know why it hasn't been cleared. And then you move. That type of high fidelity detail allows you to do what we said earlier, which is get your mind off itself. And when you do that again, typically you fall asleep faster. And that's what she found. It was a great, great study. I really enjoyed that.

Speaker A: I'm curious as to why it works so well, and I'm not challenging that it works. I can imagine having just closed my eyes and kind of imagine what that would be like. It's very pleasant. There might be, and here I'm just speculating something about engaging one's procedural memory, because that's procedural memory. You're trying to remember how you do something as opposed to declarative memory, which is about facts. I remember this, and this is going to happen tomorrow. I wonder whether or not there's something about using a procedural memory as opposed to a declarative memory visualization. Somebody should do that study.

Speaker B: They should. And I think it's certainly possible that when you're incorporating some aspect, some aspects of the scene, and the information is more veridical and maybe sort of episodic declarative memory. But when you're taking yourself from a mental walk, what is the fundamental premise of that? It's a walk, it's motion, it's procedural memory. And so maybe it's something to do about with being more attentive to becoming embodied, because when you're out walking and you're moving, it is a more embodied experience than just sitting there at your desk, which is mostly your head and very little your body. So I think it's an intriguing idea. And I think another tip that I now think of, which also comes from the work of Doctor Alison Harvey. When individuals come up to me after sort of public events or they see me at the airport, they'll say, look, every night for some strange reason, at 02:45 a.m. i wake up and it happens three or four nights a week. My first question to them is, how do you know it's 245? And they say, well, I look at the clock or I look at my phone. Best piece of advice next, remove all clock faces from the bedroom. No matter how bad your sleep is going to be that night, knowing what time it is is only going to make matters worse. It is not going to make matters any better. And that can create an anxiety trigger that you think it's 245 and then you're tossing and turning, you look back at the clock and now it's 03:14 a.m. and you think, ive got to be awake at six, ive got that big meeting and now its 525. Dont do that to yourself. And I, even though I dont typically struggle with sleep, I have no clock faces in my bedroom. The phone that I use to help do the guided meditation is an old phone and it has only wifi connectivity and nothing else on it. And I will only hit play and then I will never turn it around. I will not look at the clock face. Just doesn't help me.

Speaker A: Another incentive for keeping the phone out of the room, if one can. I understand there are reasons when one would want the phone in the room if it's potentially signaling an emergency.

Speaker B: Well, I think it's a very important point and we've done some work in this area, too. What that phone does is create a low level of anxiety. It's what we call anticipatory anxiety. One of the mechanisms separate from that, well, it's related to that. If you look at teen phone use, one of the reasons that they don't sleep very well at night is that they're constantly checking their phones because of fomo, a fear of missing out what has gone on as I've been asleep and it's stunning the data, but for most adults, the other reason I don't like advocating for phone use. When your alarm goes off in the morning, what is the first thing that you do as you're in bed? You swipe right or you unlock your phone and you instantly start checking social media, emails, text messages. And this tsunami of stress and anxiety just floods over you. It hits you like this wall of anxiety. And I bring this up because it again trains your brain for expectation of that. Anticipatory anxiety has a consequence on your sleep. And everyone knows this. Let's say that you've booked an early morning flight and you've got to wake up at 05:00 a.m. when normally you wake up at 07:00 a.m. two things will usually happen. First, you know that you're just not going to sleep as deeply that night because you're on edge. And this is for an interview or it's for critical. This is a non negotiable trip that has to happen. You've got to wake up. The second thing is that when you are expecting that wave of sort of a need to wake up and maybe it's just I'm expecting the phone again. You will wake up just a few minutes before your alarm. It's stunning how many people will say, I had this big flight the next day and you almost know I'm going to wake up two minutes before my alarm goes off. Why? Because your brain has stayed in this shallow state of anticipatory anxiety, and you don't get as much deep sleep. And we've now demonstrated that we and others, when you have that low level anxiety, the depth of your deep sleep is not as deep. You don't get the good. So again, not to be trying to dictate what people do, just be aware that when you do create that behavior and that regiment, it becomes almost like a knee jerk sort of trained habitual response.

Speaker A: Terrific. Let's talk about some of the advanced tools for sleep enhancement. What sorts of methods could one incorporate? What are some of the data? Is there any way that we can lump these into some framework or categories? Because I know there are a lot of different tools.

Speaker B: There are, and I suppose this would be, I know our friend Petra Tir has spoken about medicine 3.0. I think this would probably be sleep optimization 3.0. What is coming down the pike, what is in the research, and I think, you know, could make it to market, or has made it to market, but yet we're still right on the cusp. We've seen, we again in the royal, we have been able to augment human sleep in at least four different ways. There are methods for electrical brain stimulation, there are methods for acoustic stimulation of sleep. So electrical stimulation of sleep, acoustic stimulation of sleep, thermal manipulation of sleep, and then finally kinesthetic manipulation of sleep, meaning movement based stimulation. And maybe I can just go into each one of those. The electrical stimulation is probably the most well rendered of all of those four, in part because we started there and here. It's not the royal we. We have done a lot of work on this, and I can tell you a little bit about a company emerging from that. But when you're trying to manipulate the human brain, the principal currency in which the brain communicates is electricity. Now, there are lots of things that help it do that, such as chemicals. But the principal language and verbiage of the brain is electricity. So if you're going to manipulate the brain, why don't you speak in its currency of electricity? So we and others have developed a method based on something called direct current brain stimulation, and specifically something called transcranial direct current stimulation. And I'll unpack that. Trans meaning movement. So if you've heard of transport, it's about moving things from one port to another, transatlantic, moving across the Atlantic. So here the start of it is moving. You're moving something from one place to the next. Transcranial means through your skull, so we're moving something through your skull. Transcranial direct current is the type of voltage or the type of electrical impulse that we're putting in, it could be alternating current or it could be direct current. And early methods and those we use have been direct current. So transcranial direct current and then stimulation. We're trying to stimulate the brain, specifically the cortex. And the way that we do this is that we apply electrode pads to your head and we insert a small amount of voltage into your brain. Now, it's so small that you typically don't feel it, but it has a measurable impact on that electrical brain activity. So very early on, scientists, and we weren't the first to do this by any means, there was a great paper, now famous paper in my field by wonderful scientist Jan, born in Germany, and they took a group of subjects and they applied these electrode pads and specifically to the front of the brain, and I'll explain why. We target the front of the brain with sleep electrical enhancement, or the electroceutical, as it were. They applied these electrode pads to two groups of participants and then they let them go into sleep. And as you'll remember, we described that in the first two or 3 hours of sleep is when you get most of your deep sleep. And they were targeting those deep, slow brain waves that we spoke about, those big, slow, powerful waves that define deep sleep. And what they did in one of those groups, the other group was the placebo group. They still had the electrodes applied, they still went to sleep. In the stimulation group, they waited until those individuals went into deep sleep. And I told you in the first episode that those deep sleep brainwaves were going up and down very, very slowly, maybe just once or twice a second. So they started to stimulate the brain, inputting these stimulation pulses at a very slow rhythm, trying to match the rhythm of the brain. In fact, they were less than 1 hz, less than one cycle per second in terms of a pulse. It's almost as though we're trying to act like a choir to a flagging lead vocalist. And as these brainwaves are going up and down, you're trying to sing in time with those deep sleep brainwaves, and in doing so, you're trying to boost and amplify the size of those deep sleep brainwaves. Now, to begin with, they just waited until they went into deep sleep and they started to stimulate at that frequency. And I'll come back to why that's important in a second. But sure enough, what they demonstrated, they were able to boost the electrical quality of that deep sleep by about 60%. And they were also able to almost double the amount of memory benefit that sleep provided, which is very impressive.

Speaker A: That is impressive.

Speaker B: Now, I should note that there was more recently a replication attempt of that paper, and they did a very good job. They really did it to the letter, and they weren't able to replicate the effects as powerfully. However, subsequent studies have now taken a more nuanced approach. And it's the one that we've taken, too. And it's called closed loop stimulation. Closed loop here simply means that I'm not going to just wait until you go into deep sleep and then just take a chance and start stimulating your brain, not knowing of the synchrony of my pulses into your brain relative to the brainwaves that you're experiencing. Closed loop does do that. So what I'm doing is I'm measuring the electrical brain waves that are occurring. And because they're nice and slow, they're very predictable. And I can program my algorithm and my brain stimulation machine to say I'm going to wait and wait. And as soon as you are on this peak of your slow wave, it turns out to be the negative trough. But I'll forego that. We then try to strike at that point of midnight when you're going through the biggest sort of powerful dip in the brain wave. And we're trying to sort of enhance it. And same with the peak. So this is where we get a stimulus from the brain, your electrical brain activity, and then we create a timed response. So it's a stimulus response, it's a call and response loop. And by way of doing that, it's a much smarter specific method of than a more generalized Im just going to stimulate and hope I catch those waves at the peaks. The reason is important because different people have different speeds of their slow brainwaves. Theyre all slow, but your speed of brainwave may be a little bit different to mine. And if Im off with my stimulation by, lets say, just half a second or a quarter of a second time and time again, I may be leaving some benefit on the table. But closed loops stimulation creates this personalized electrical prescription of stimulation. And when you do that, you get very reliable benefits. You can boost those deep slow brainwaves, you get the memory benefits. But also what we found is you not only boost those deep sleep brainwaves, you boost another electrical signature that I spoke about in the first episode called sleep spindles. And it seems to be the combination of those two things by way of electrical stimulation that provides the benefits. Now, I should note, I haven't mentioned this before. You can buy these devices on the Internet, DIY style. Do not do that. If you go onto the Internet too, you can also find some horror stories. People have misappropriated the voltage. They've got skin burns, they've lost their eyesight for several weeks. Do not do this at home. I promise you. Wait until these products come out. And that's one of the reasons why we've scaled it into a company and we're trying to do this. We've got a long way to go yet. Huge number of trials that we have to do before I feel ready to really lay it on the table and say, you should absolutely buy this. It's well worth it. But we're getting very, very close. I would say great.

Speaker A: Thermal manipulations, temperature. I mean, there's such a tight relationship between temperature and sleep and wakefulness, for that matter. What sort of technologies, tools, protocols exist that use thermal manipulation as a way to augment sleep.

Speaker B: I love this topic because there are hi fi, lo fi and no fi technologies that you can use. The story of sleep and temperature, as you mentioned before and reiterated in terms of the three part stanza, that terset that I would describe is, again, you need to warm up to cool down to fall asleep. You need to stay cool to stay asleep. You need to warm up to wake up. What that refers to technically, in sleep science are what we call the thermal trigger zones. So warming up to cool down to fall asleep is what we call the sleep onset thermal trigger zone. Cooling down or staying cool to stay asleep is about the deep sleep trigger zone. And then warming up to wake up is the activating alertness trigger zone. Studies, if you looked at them to begin with before they manipulated that, found something fascinating. If I take you, Andrew Huberman, and I bring you into my lab, and I remove your phone, your laptop, and you say goodbye to your friends and family, and I bring you into the center, and there are no cues as to what time of day, no windows, no nothing. And I'm just going to say, look, I'll keep asking you, but at the moment that you feel most sleepy, just let me know. It turns out that before that, we'd done the delightful intervention of inserting a rectal probe into you because that's the best way that we can measure your core body temperature. So we're measuring your core body temperature. And sure enough, despite you knowing nothing about what time it is, the moment that you will tell me I am ready to go to bed and I am sleepy is the moment when you are on the greatest decelerating trajectory of your core body temperature. It is highly predictive of how sleepy you will feel. The way that your body does this is by pushing blood out to the surface regions of your skin, notably your hands and your feet, because these are these highly vascular regions. And you had a great podcast from one of my heroes and good friend, Craig Heller, who's done some amazing work on this at Stanford. So, naturally, as we lie down, blood races to our hands and our feet and also our head, and we start to release that heat trapped in the core of our body. And by releasing that heat at the surface, our core body temperature drops. Hence the outer surfaces of you hands, feet, and face have to warm up for your core to cool down, for you to fall asleep. And in fact, there was a great nature paper some years ago. They just measured the temperature of someone's feet, and they looked at how quickly they fell asleep. And when they fell asleep, sure enough, the warmer your feet, the faster you fell asleep. Why? Because the warmness reflects the blood dilation and the pumping out of the blood to the periphery. And then they did it in rats, where they started to warm the pores of the rats, and the rats fell asleep more quickly. And I love this notion of, again, we don't do animals, but I love the notion of wrapping a beautiful little wrath up in cotton wool, and I'm warming its feet with this pad, and it's just blissed out, and then, poof, he's gone. After all. She I respect their privacy. So that was the early evidence that then led to a series of manipulation studies. The most notable is brilliant. It comes from a colleague in the Netherlands, us van Sumeren, and his group. They created essentially what was a wet. Think about a wetsuit. But that wetsuit is covered with all of these thin tubes, almost like veins, that go all over the suit to all territories of your body. And then what they would be able to do is perfuse water, warm water, or hot water, exquisitely to different parts of the brain or the body. Cool. Amazing. Yeah, no pun intended. So what they did was then they started to manipulate these peripheral regions, sort of. And sure enough, when they did this, they were able to have individuals fall asleep 25% faster. And these were healthy individuals who are normally sleeping within a very natural, quick period of time. But they were able to lop off 25% of that time simply by warming these certain parts of the brain to lift the blood away from the core of the body. And by doing that, they accelerated the temperature, core deceleration, and therefore increased or accelerated the speed with which sleep arrived. To those individuals, sleep appeared with much greater alacrity than it would have done otherwise, even though it was quick anyway. So then, not being satisfied with that, they moved on to the deep sleep trigger zone. And this isn't. You need to stay cool to stay asleep. And here now they started to just continue to cool the core, the central aspects of the body. What they were able to do is increase the amount of deep sleep by somewhere between 25. To look at some of the data, almost 40 minutes. They were able to boost the amount of deep sleep with the thermal manipulation. And when they were measuring the electrical brainwaves and they decompose those brainwaves, even the power and the electrical quality of those slow waves was increased. Very impressive, too. Next, not being satisfied with that, they turned to older adults for the reasons that we've just described. What they found was that in those older adults, when they were not manipulated with this thermal temperature in the second half of the night, there was a 50% probability that they were going to be awake for some part of the second half of the night. When they did the thermal manipulation, they dropped that number down to 5%. So they reduced a 50% probability of waking up down to 5% in older adults. And again, they improved the quality of their deep sleep. Think about, by the way, why that was so effective for older adults. I guarantee you, you've probably seen, you've been in a warm climate, or you've been down on the beach here, sort of in Los Angeles, and people are out in shorts and t shirts or crop tops. And then occasionally there will be someone, and I love seeing these sites where a child is sort of wheeling along their elderly parents, a beautiful sort of scene occurring. But the older adult, they're not dressed in the same way that everyone else is dressed on the beach. They are wrapped up. Some of them have a woolen hat on. Why older adults cannot thermoregulate anywhere near as well as young adults.

Speaker A: Is that right?

Speaker B: And it's the reason that older adults will always be saying, I'm just so cold. And my hands and my feet, especially, are always cold. Now, that's a problem for sleep, because if you cannot vasodilate at the level of your hands and your feet, you can't get the blood out from the core. You can't drop your core body temperature as much. And we started to understand from those types of data that part of the aging sleep related problem equation is not just that the brain deteriorates in sleep related regions, which we've been doing most of our work on. It's also part of a body equation and a thermoregulatory equation. There was also a great study, unrelated from Australia. They looked at insomnia patients and they put their hands or their feet in warm water. And by doing that, it's a manipulation. You can see how quickly their hands and their feet, what we call vasodilate, filled with blood. Healthy people vasodilated very quickly in response to that warm water, meaning that their hands and their feet had this reduced, or at least for my feet, they would be this red tone to them. However, in the insomnia patients, they did not vasodilate anywhere near as well. So, once again, it suggests that when you have problems with sleep, part of the equation may be that you have impaired thermoregulatory ability. And we do see this in insomnia patients. So that was, I think, a brilliant causal manipulation. The problem is that most of us don't have access to a sort of come to bed eyes thermal suit. So what can we do? As a consul, please don't cut that. I get myself into terrible trouble, rightly so. I should be punished.

Speaker A: You'll be all right.

Speaker B: What they did then was to say, well, okay, let's look at this. Is there something that we could do that's cheaper and more accessible to the general public? And if you look, there's a literature that preceded that manipulation, and it's so reliable that we now have a term for it in sleep science. It's called the warm bath effect. And many people will say, look, I love to have a warm bath or a hot shower before bed. And I think when I get out, I'm nice and toasty. And it's because I'm nice and warm that I fall asleep and I stay asleep. It's the exact opposite. When you get out of the warm bath or the shower, you have once again vasodilated at the surface of your skin. You get out of the bath, you get this huge thermal dump of heat away from the core. What happens? You fall asleep and you stay asleep more soundly. Now, there are other reasons that that has a benefit. It's relaxing, you decompress, you're staying away from technology, et cetera. But that is one of the thermal benefits. And in fact, there were studies by a legend in my field who passed away just a few years ago, Jim Horn at Loughborough University in the UK. And they did some of these pioneering studies. They were able to improve the amount of deep sleep by almost 40 minutes in some individuals. What was the protocol there? As I recall, I think they were in the bath for somewhere around or the bath duration time was somewhere around 30 minutes, but they were doing sort of segments where it was maybe it was 40 minutes, ten minutes in and then you could sort of get out. I think the temperature, because it was UK, was around about 40 degrees celsius, somewhere in that region. I may be getting those numbers wrong because I know we like to protocolize some of this, but they were able to show some really pleasant benefits to deep sleep. It also helped people fall asleep, helped them fall asleep by about 25 minutes faster in those people who were really having a hard time with sleep.

Speaker A: I'm going to take a hot bath tonight. I sometimes do the sauna in the evening before sleep. I'm a big fan of cold in the morning, cold shower, cold plunge in the morning.

Speaker B: Reverse engineering the equation. You're trapping the heat into the core of your body. You're waking yourself up, right.

Speaker A: And in the evening I've used sauna. The one issue with sauna is I really crank the heat of the sauna. And then sometimes if you do that right before bed, you take a warmish shower right afterwards, you get into bed. Oftentimes I'll wake up thirsty and then. Cause it dehydrates you. And then if I drink a lot of water to hydrate after I'm in the sauna, then I'm waking up too much in the middle of the night. So I think sauna is great. But right before bed, I would love to.

Speaker B: I don't have a sauna at home or nor an access to. I mean, there are saunas in and around where I live, but what I want to do is have it proximal to my bedtime and my bedtime. Cause I'm a neutral type, you know, sort of around eleven ish. Nowhere is open and willing to allow me to sit in the. So how long do you sit in there?

Speaker A: Usually I'm a little bonkers about this. Well, if it's in the evening and I just want to relax, I would say maybe 2030 minutes. And I tend to go really warm, warmer than I want to hear.

Speaker B: What is Peter do, Petri? T our friend?

Speaker A: I've done sonic cold plunge with Peter. He usually does it in the evening. Goes sonic, old sonic. Old sonic cold. Okay, warm shower. And I don't know how many nights a week he's doing that. But in terms of the temperature of the sauna, generally somewhere between 175 and 210 degrees, depending on how heat adapted you are. But I think a hot bath is great. Or a nice hot shower.

Speaker B: Yep, I've certainly done that. And when I'm traveling with jet lag, I will. Absolutely. That's part of my sort of jet lag protocol. I'll make sure I do, because I don't really struggle too much with sleep, at least at present. But when I go through jetlag and I go back home to London, of.

Speaker A: Course it's tough, the worst.

Speaker B: Criticalize the living daylights out of that and do as much as I can. So I think that's probably the end of the thermal story. Although we are now trying to see if we can take lo fi approach as well. We're going to do some footwarming. We're trying to develop some footwarming technology that can be built into maybe a mattress and some mattress companies. There are some great ones. I know obviously Matteo at eight sleep and they are doing amazing things. I think his company, again, I have no affiliation, but we connect very well and he's brilliant. So they're doing something like that.

Speaker A: I do use and love my eight sleep. Here's what I'd love somebody to engineer, and we've got a lot of people who listen to the podcast who think about product development. It would be wonderful to have a portable pair of socks so that you can use them when you travel or when you go sleep anywhere at home or elsewhere. That would warm your feet up at the beginning of the night. So this is a place for us to recap. Warm up, to cool down, to fall asleep. Right. Stay cool. Stay cool. To stay asleep and then warm up in the morning to wake up. And so that is pretty straightforward to build into a pair of socks. Somebody can do this. Somebody do this.

Speaker B: Okay, so we've done electrical, we've done thermal.

Speaker A: What about auditory?

Speaker B: Auditory. So acoustic stimulation in a very similar way to electrical stimulation where you're trying to target that deep sleep and see if you, a better analogy is probably a metronome and you're trying to see if you can force the metronome further over and back and forth with these types of technologies. So auditory stimulation came on the map again. I think probably Jan Born's group in Germany was some of the first to do this. They initially started with this same generalized approach where they would take acoustic tones and they would first assess what is your level of awakening threshold. So you'd be asleep and they would just have these tones, very light tones, like a sort of ping ping. And they would gradually increase the volume up and they would look to see what is the point where that volume of the tone wakes you up. And then they understood your specific threshold, what's called an awakening threshold. And they would set the volume to a subawakening threshold. Great. So you've got that locked in place. And now you start. And they did this within the first 90 minutes of people falling asleep. They started to play these sub awakening level, volume levels of tones, but they were playing them at this very slow frequency, as if, again, they're trying to sync and match the slow dancing rhythm of the slow brain waves. And sure enough, in that first study, and it was indiscriminate, meaning they just set the tones playing like a metronome. Set the tone, set the. And then, sorry, set the volume, and then set the cadence of the volume, the speed, the frequency of those tones to just a little bit less than 1 little bit less than one cycle per second. And then off you drifted to sleep. And they played it for the first 90 minutes because that's the rich phase of deep sleep. And they were able to increase the amount of deep sleep significantly. The problem in that first study was that they also did a memory test, because in all of these studies, including my own, even if I boost your sleep tonight. Andrew Huberman, my next if that's the result that you show me, I have four words for you as a scientist. Yes. And so what? Is it functional? Because if I boost your sleep but it doesn't change anything to you, the organism, the next day I'm going to suggest that that enhancement is epiphenomenal, not functional.