WHOOP Podcast - Understanding sleep debt and the adverse health effects of sleep deprivation

Episode Date: March 16, 2022

This week's episode is a deep dive on sleep debt and how sleep deprivation affects your body. VP of Performance Kristen Holmes is joined by sleep expert Dr. Allison Brager, a neuroscientist and a Major with the United States Army. Dr. Brager's research has covered survival in extreme environments under sleep deprivation and stress, and serves on fatigue management and neuroenhancement working group for NATO, the Office of the Army Surgeon General, the Department of Defense, and NASA. She discusses what sleep debt is (3:38), why sleep need is highly individualistic (5:17), how mindset plays a role in sleep, recovery, and performance (13:00), what caffeine does to your body (16:48), sleep fragmentation (20:28), the toll sleeplessness takes on your body (23:06), sleep and wake timing (28:47), eating close to bedtime (35:05), and tips to manage insufficient sleep (37:54). Support the showFollow WHOOP: www.whoop.com Trial WHOOP for Free Instagram TikTok YouTube X Facebook LinkedIn Follow Will Ahmed: Instagram X LinkedIn Follow Kristen Holmes: Instagram LinkedIn Follow Emily Capodilupo: LinkedIn

What's up, folks? Welcome back to the WOOP podcast, where we sit down with the top athletes, scientists, experts, and more. Learn what the best in the world are doing and learn what you can do to perform your best. All right. Woop is on a mission to unlock human performance. I'm your host, Will Ahmed, founder and CEO of Woop. And this week, we got a great episode. We're going to go deep on sleep debt and how sleep deprivation affects your body.

But first, a reminder, you can use the code will, W-I-L, get 15% off a W-W-W-Mership, actually have a tool that really accurately measures sleep, among other things, recovery, exercise, the health monitor, bunch of great features. Check that out. Woop.com. Use the code Wilt. Our VP of Performance, Fearless Leader, Kristen Holmes, is back and joined by sleep expert Dr. Allison Brager. Dr. Brueger is a neurobiologist and a major with the United States Army. and her research has covered survival in extreme environments under sleep deprivation and stress. So those of you who think you work a little too much and have trouble sleeping, these are going to be some extreme environments that we're talking about.

She sits on fatigue management and neuroenhancement working groups for NATO, the Office of the Army Surgeon General and a variety of government agencies, including the Department of Defense and NASA. She's also a member of the Whoop Women's Performance Collective. Kristen and Dr. Brager discuss how to understand sleep debt and sleep need, groundbreaking whoop research about how sleep debt affects our next day cognitive functioning, what we know about banking sleep before anticipated periods of less sleep, why fragmented sleep can have such a negative effect on us, and everything you need to know about caffeine and how it impacts the chemicals in. your body. This is a fun one. It's a really good one if you're into sleep. And without further ado,

here are Kristen and Dr. Breger. Dr. Allison Brager is a neurobiologist with expertise in sleep and circadian rhythms for the United States Army. Her work examines the substrates and mechanism of resiliency to extreme environmental stress, including exercise, jet lag, and sleep deprivation. Dr. Breger has over 30 peer-reviewed publications in flagship journals and is the author of a very popular science book entitled Meathead Unraveling the Athletic Brain. And by the way, no big deal, a two-time CrossFit Games and regional competitor. Few, Allison, welcome. Oh, it's so great to be here. I'm just so stoked to talk about sleep, especially since it's a sleep awareness month. Exactly. Yeah,

it's very topical and just being able to leverage your expertise and kind of all things sleep is going to be really cool. And I'm excited to kind of tap in, particularly to sleep deprivation and really try to help folks understand exactly what that is, what it looks like. And I think most importantly, the strategies and tools to kind of break the cycle of sleep debt. You know, as we know, our world isn't really set up to kind of facilitate optimal sleep. So, you know, it's, I think, something that we have to really develop boundaries and skills around and can't wait to get your perspective on all of that. You know, obviously as a soldier and, you know, you've experienced firsthand, the conditions of sleep deprivation, and obviously as a scientist, you've been able to

research the effects of sleep debt. Maybe start by just kind of outlining, you know, what is this phenomenon of sleep debt? And maybe how it's different from poor sleep. Okay, so sleep debt is different than poor sleep, because sleep debt is basically poor sleep accrued over time. You've heard this analogy before. We think of sleep as a bank account. And so the more you take out, the more you have to repay. Now, you can actually bank on sleep, and we know that phenomenon works because we have done countless studies at Walter Reed to show that loading up on sleep prior to anticipated sleep deprivation improves cognitive, emotional, and even such things as pain tolerance. So that is like how we think of the relationship of sleep debt. Now, poor sleep is a component of sleep debt.

So poor sleep can be a single night of sleep deprivation, or of poor fragmented, unconsolidated sleep. So obviously a whoop score that is in the red. But then you can also have poor sleep where you consistently have scores in the red, even if you're doing all the right things, such as sleep coaching, hydration, nutrition, et cetera. But yeah, sleep dead is the biggest problem. So that's like the macroscopic problem. and poor sleep is an element of sleep debt. Got it. That makes sense.

It does. Yeah. Now that we kind of have an understanding of just, all right, what is sleep debt? Let's talk a little bit about set points and just how everyone has kind of a different sleep need. And then we can kind of back into some of the components of sleep deprivation. But I think that it's important for everyone just to understand that we don't all need to spend the same amount of time in bed and kind of what influences that.

And what do you know about it based on your research? Yeah, that is an excellent question. And that's one I get asked a lot. So obviously the recommendations of the American Academy of Sleep Medicine and the National Sleep Foundation is between seven and nine hours per night. And the reason that is is because the international average of sleep need is 8.4 hours. That is something that has been determined through years and years of anthropological and very large-scale epidemiological studies of sleep in different cultures.

So it's not just factoring in how Americans sleep. It's Europeans and even like tribal communities in sub-Sahara Africa. Like 8.4 is the human biological need for sleep. But there's a huge standard deviation and standard error with that. And we know that, especially when we look at high performers in systems, society. So historically, if you look at the U.S. presidents, most of them are short sleepers. Bill Clinton is probably the most famous president who only needed about three or four hours per sleep per night. President Obama was similar. Same with CEOs and executives.

You know, I used to think when I first heard about how little Elon Musk slept, at first I was like, well, that explains some of his other behaviors. But then I started to realize it's like, no, there actually are a handful of corporate executives who have essentially self-selected because of being short sleepers, which is a rare genetic mutation. That's what I like to emphasize. It is because of a rare genetic mutation of a gene called DEC2, DEC2, that they are able to do that. But most of the population falls within the bell curve and normal distribution of needing 8.4 hours per sleep. per night. And unfortunate people are in the far other tail of the distribution where they need

10 to 11 hours of sleep per night. It's called hypersomnia. And it sucks for them. But unfortunately, their genetic programming has wired them that way. Yeah, that's an incredible explanation. And I think it's, you know, because I think these leaders are obviously so visible and their sleep habits are talked about, people think that that's okay. I can adopt that. lifestyle as well. But I think to your point is a very important one that this is a very small percentage of the population have this gene. And in fact, you know, folks are being pre-selected into these fields. You know, that actually require less sleep at night, which is, I think, I've never actually heard that point made. So I think that's really interesting. Yeah. I mean,

quite honestly, and I've told soldiers this before, generals, they're the same way, where they pre-select as short sleepers and then also early morning people. I am a vampire. My parents are vampires. pires and I need eight hours. So I will never have any hopes and dreams of ever being anyone important at that level in the military because my genetic programming does not conform with that. And if I tried, I would probably get sick. So just as it relates to kind of the Woot Platform, we have what's called a sleep need algorithm that basically tells you based on a whole bunch of different factors how much time you actually need to be spending in bed. The algorithm looks at your baseline sleep need. It looks at sleep that you've accumulated. It looks at your day strain.

It looks at any naps you might have taken. And then basically we give you a sleep need recommendation. I remember we were talking about these recommendations and a lot of sleep scientists push back on this sleep need recommendation for, you know, it's a black box. It's an algorithm. It's proprietary. We don't share it. But one of the kind of my personal missions, you know, it just seems really on point in terms of, you know, when I listen to whoops, sleep need recommendations, like I fare much better. And that goes for, you know, like, I'm not good if I spend too much time in bed. So if I oversleep, I end up with a poorer recovery the next day. So, you know, it's just the end of one and all the data that I was, you know, I've been exposed to,

it just seemed to really prove to be, you know, valid these recommendations. So we did a study in collaboration with the University of Queensland, University of Melbourne, and we looked at basically the influence of sleep, stress, and HRV on cognitive control. And one of the kind of happy findings of the study is, is we saw that with individuals who accumulated 45 minutes of sleep debt, they had a 5 to 10% decrease on next day executive function and cognitive control. It was just like this really happy finding in that it kind of validated, you know, kind of in a backdoor way, validated these sleep need recommendations because we saw on these cognitive control tasks, we saw, you know, very clearly decrements in kind of these cognitive tasks. So it was kind of

an interesting, yeah, so just love to get your thoughts on that. Well, I'm sure, let me ask you this first. Was it an exponential relationship and that the greater the delta between sleep need and actual sleep reported, there was greater cognitive? Yeah. So the more, so that was just, you know, at 45 minutes, we saw 5 to 10 and then at 90 minutes we saw greater, you know, it wasn't a perfect exponential relationship in the sense that it wasn't 5%, let's say at 45 minutes, and then at 90 minutes it was 10%. It wasn't like that, but we would see 11% decline in some individuals. But so it was, it was definitely, it would, there would be a dilettarious effect, an increasing

deleteries effect, the more time, the more sleep debt you accumulated. Nope, I'm not surprised at all. So that actually mirrors the findings that we found out in the operational environment when we're looking at sleep amounts in combat effectiveness. So the Army has actually been doing this since the Gulf War. I don't know if you know this. The Army developed the first act of watch back in the 90s. now retired Colonel Greg Belinky, wonderful, huge contributor in the sleep field. And he's really the

reason why I came to Walter Reed is because I wanted to carry on this legacy that Greg built. And he found, like, direct relationships between total sleep time, downrange, and next day military performance. And when I was deployed four years ago, and we did a similar study with the first armored division back down in Kuwait. We found very similar results where however much sleep they had 24 hours prior mirrored how they performed on marksmanship activities with Abrams tanks. So it's not a surprise. And I think it's very similar to what we see in the lab, like the classic lab studies where

they use the psychomotor vigilance test, which is a test of reaction time. Very valid. You see an exponential decline in performance based on hours of lost sleep. Yep. I think I feel like I read that. It starts at like 100 milliseconds, right? Like it's like something like and it just goes to shit after that like. Yep, exactly. Maybe we can kind of dig into just the physical and psychological symptoms of someone who's experiencing sleep debt. You know, I think obviously if you're wearing whoop, you can kind of start to see it accumulate. A lot of times folks actually can't perceive their own cognitive physical declines. So maybe start there with just maybe the literature on do we even know if we have sleep debt? You know, like I say we don't. We don't have access to a whoop, we're not looking at our sleep architecture. How do we know that we're not getting sufficient sleep? Sure, and I definitely think it's all related. So despite all these technologies we have now at our disposal to monitor and mitigate any amount of sleep debt and all the objective measures we have to look at sleep debt. I mean, we can even predict sleep debt now

through neuroimaging. But despite all of that, the single one question that is still the most predictive factor of if somebody will have decrements and next day performance is if you ask somebody when they wake up in the morning, how well did you sleep? And based on their answer, it almost mirrors how they perform. So even if they got crappy sleep, like say they're an athlete competing in the cross at games, they got crappy sleep the night before, but they kind of expect they're going to get crappy sleep. If they wake up and they're like, well, I slept okay given the circumstances, They are more likely to have their performance protected because the brain is a very adaptive organ and it will find a way to protect that individual because it is in the psychological state that

I am ready to perform. Now, that's under a certain circumstance though when you're otherwise sleep satiated. So people who are chronically sleep deprived, that question actually would not hold true but in a normal healthy sleeper whose sleep satiated, that question would hold true. So your mindset can move you around pretty significantly and protect you if you actually are functioning on lower sleep. And we definitely hear this anecdotally all the time, you know, that I had I PR'd and I got two hours of sleep, you know, or, you know, some people actually literally cannot

sleep at all prior to like a big competition. But I think to your point, if they have good sleep leading up to that event, that event, that night sleep in of itself is not going to impact next day performance. and they will be able to compensate with just, you know, their mindset and just getting themselves into a place where they can compete. That's interesting. Do we know when we no longer have the ability to kind of tap into our mindset, to kind of move that around?

Like, what does that point? Three days. And we know this from quite a few studies. We know this from an endocrine perspective. If you look at the classic studies, looking at drops in testosterone with sleeping only five hours a night across a week. Day three is the tipping point. And we also know this from studies we've done at Walter Reed with cognition, that cognition continues to decline until sleep needs are met again. And that caffeine actually has zero protection against that decline

by three days in. So we've studied this a lot of different ways, but three days of chronic sleep debt where you're basically losing about 60% of your total sleep amounts. So that's the thing. It's not going to be five hours for everyone. It's going to be 60% of your daily sleep meet by day three of only getting 60% you're you're on a, you know, cataclysmic decline. Wow. So people who are drinking caffeine and thinking they're, you know, they're basically just making bad decisions faster. Is that way? Yeah, pretty much. Actually, funny enough, so in this study, it was published in the flagship journal of sleep. One of my colleagues published it, Dr. Tracy Joe Doty, she found that the caffeine group actually performs worse. So the people who are supplementing with caffeine on, you know, the same amount of sleep debt as somebody who wasn't supplementing on caffeine, they actually perform worse by post-day-3 because they no longer have that protection of caffeine and they know it so their mindset changes and they don't perform well again until they get sleep again.

To the points you're just you're just making, we use caffeine to make up for lost sleep or, you know, it help us perform. Like, what is actually happening there? Because I think people think that that's a substitute for sleep in a lot of ways. So maybe take it from that angle and kind of talk about how that's not the case and how we need to reframe or rethink our relationship with caffeine. That is the best question you have asked so far because that's exactly what people think is that you can replace sleep with caffeine. And as I said from that one study, that is not the case at all. So the reason why caffeine is effective is because it prevents the release of the neurochemical adenosine. So adenosine is a neurochemical that is released by glia cells that

increases as you become more sleepy. And so throughout the day, from the moment you wake up, the moment you go to bed at night, you see a precipitous increase in adenosine. But what caffeine can do is it can block the rate at which adenosine is increasing, and so thereby it can minimize overall sleepiness if you adhere to a very specific caffeine dosing schedule, which we can get into later. But the problem is, even if caffeine is decreasing the slope of, of adenosine release, you still need to make sure that you replenish the system. And so caffeine cannot do that.

The system has to be replenished through sleep. And the reason for that is because sleep is then when adenosine triphosphate, which is one of the main sources of adenosine, needs to be replenished. So all the basic cellular energy substrates of creatine, adenosine triphosphate, adenosine diphosphate, all that stuff that we need in order to stay alive and function only gets replenished with sleep, not with a supplement like caffeine. I think we can say that, you know, stimulants when group recovery is low, is not going to help you recover faster.

That's one of the things that we really have worked really hard at Walter Reed to sort of nail down, is this precise dosing of caffeine administration. We know that 200 milligrams is the maximum amount of caffeine you can handle at any given time. Anything else is more or less a sealing effect. Beyond just 200 milligrams, you can only take 200 milligrams every three to four hours. So that's another thing you have to consider. It's not just the amount, it's the timing. And as long as you stop six to eight hours before bed, you're fine because the metabolism

of caffeine, it does extremely vary by individual. And that's also genetically determined. But six to eight hours is a good time frame where you could still get, you know, sleep, even if you're supplementing with caffeine three or four different times throughout the day. I mean, I routinely do that, but, and it, you know, I have no issue sleeping at night. We all metabolize caffeine a bit differently. that, you know, range is going to change slightly from person to person or very from person to persons. You kind of have to play around it and figure out, all right, look at your sleep on set

latency. You know, look at your, you know, that kind of early bit of sleep, I think, to know to know whether or not it's actually impacting you. But I think, too, like with folks with chronic sleep deprivation, caffeine is probably not going to, when they go to put their head on the bed, even though they may have had caffeine at like seven o'clock at night. Like, they're so exhausted. They're going to fall asleep quickly. But maybe talk about the fragmentation that occurs, you know, which just kind of further contributes to kind of this poor sleep cycle. Yes, that's a great point because I think that's one thing we don't talk about enough. And I was having a conversation yesterday with somebody about this is like we care so much

about sleep amount that we forget that actually one of the biggest culprits of poor sleep and the biggest contributors to all the health factors that result from poor sleep is sleep fragmentation. That is the key. Like all those people who have sleep disorders, it's not so much their lack of sleep, it's their inability to cycle effectively through sleep cycles because they're constantly being woken up and can't complete a sleep cycle. And so caffeine can have a very similar impact is like, sure, you might be exhausted enough

where you fall asleep, but you're still going to pretty much stay because of the adenosine blockage in the lighter stages of sleep and not reach the most deep. restorative stages of what we call non-REM slow-wave sleep. Because actually the expression of slow-wave sleep is dependent on adenosine circulation. And so when adenosine circulation is low, because it's inhibited by caffeine, you're not going to get slow-wave sleep. But if adenicine circulation can be high, then you're going to get the restorative sleep, where you get the testosterone boost, the growth hormone boosts, and all the physical restoration. you need in order to function the next day.

Maybe I'm overstating this, but I know that some sleep researchers have almost, I think, claim a causal effect between kind of sleep deprivation and Alzheimer's, cognitive Klein and eventually Alzheimer's. Can you talk a little bit about maybe some of the research that exists around that and what's happening in the brain, you know, when we're not activating kind of this sewage system? Exactly. So the sewage system you're referring to, this process of waste clearance and regeneration of neuronal connections is called the glymphatic system. And that's basically what it is. It's a sewage system for your

brain. And during sleep, what happens is the glymphatic system, it's fluid-based. So during sleep, the vessels or the pipes of the sewage system are bigger than they are during wake. And if they don't have the opportunity to be bigger during sleep, then it decreases the flow and the flushing out of these wastes and toxins from your brain and your body. And so that's one of the key findings related to Alzheimer's is because we find that Alzheimer's is a direct relationship with neurotoxic buildup of these plaques. And then also when you talk about,

they're called neurofibrillary tangles, they result because of not having the ability of sleep to go through the repair processes. there's almost irreversible brain damage that results from this sleep deprivation and this inability to clear these beta amyloid plaques because of reduced sleep. Well, you know, I don't want to terrify folks without giving them kind of tools and strategies. So we will get to tools and strategies. Oh, I know.

I know. But, you know, I think that this is part of the public health education, right, is understanding the impact, you know, of short sleep and insufficient sleep, low quality sleep. and you know how that impacts our longevity and and maybe if we can just talk in addition you know we just talked about what's happening in the brain but you know maybe just the linkages of sleep deprivation to things like cancer and you know cardiovascular disease and obesity and you know some of these other you know kind of significant health problems and knowing that root cause is is insufficient sleep sure well we do know now that shift work is considered to be a level two carcinogen

by the World Health Organization. We know on average now that shift work, which always results in insufficient sleep, takes about 10 to 15 years off your life and significantly increases your risk for cancer, especially if you're already at risk because of your family. And then same increased risk for metabolic and cardiometabolic disorders. With the reason being is because you miss out on these opportunities to repair the body. I mean, that's essentially what happens during sleep. you have whole body and whole brain repair.

The whole brain repair, a lot of that happens during REM sleep, but the whole body repair is like what the deep restorative sleep is for. And if you already have a sleep disorder such as sleep apnea, well, you're never going to fully activate those repair processes because unless you're treated for sleep apnea, you're missing out on the ability to even enter those deep restorative stages of sleep because your body is waking you up well before that because you can't breathe. You said before that it, you know, it's kind of your sleep is going to start, you know, the kind of the moment you wake up in the morning. And, you know, shift workers obviously aren't having the benefit of natural sunlight. And, you know, they're working during the night and sleeping during the day. You know, talk a little bit about what other cues can those folks anchor to to help regulate the system and maybe mitigate the effects of not getting the light exposure that they need during the right times. Just that signaling isn't activating. So I would love to hear you talk about.

We can maybe start to get into some tools now and start there. Yeah. No, that is an excellent question. So I think the biggest thing with shift workers is knowing this information now, and a lot of companies I think are going down this road, they need to be disciplined. Just like an athlete needs to be disciplined in their nutrition, a shift worker needs to be disciplined and their exposure to light.

So that means when you're on shift, like try to minimize that crappy white light. A lot of companies now are investing in blue-enriched light to just optimize and mimic natural sunlight exposure as much as possible. Do not wear blue light blocker glasses when you need to be getting light. So when you want to be alert. Exactly. I don't know what happened to our world with the blue light blocking. I'm like, don't block the blue light. When you want to be alert, when you want to be alert.

That is exactly it. You use those blue light blocking glasses when actually you're driving home from your shift in the morning. And it is sun out and you have to wear shades. And like, yes, that's, you have to maybe supplement with caffeine too because that is somewhat dangerous, like, because they're already sleepy. But that's going to at least set them up for they can take like their first long nap and then do things in their day and then take an additional nap or get an additional sleep period with, again, blocking out the light. So they're basically on a reverse. schedule of humanity where they have to pretend that when they're working, they're out like where I am now in South Florida, like exposed to sunlight all day. And then when the rest of the

world is experiencing sunlight, they have to be vampires and block out the light as much as possible. So the message to folks is when you want to be alert, you want to get as much blue light as possible. When you need to be sleepy, you want to try to block that light as much as possible. And that applies if you're up during the day, that applies if you're, you know, sleeping during the day. Like, you use that as a principle. And then maybe just talk as it relates to this as we think about strategies to reduce chronic sleep dead and get folks kind of on a better path. You know, obviously the light behavior is massive and that's a strategy and a tool. Maybe talk about, you know, the other three core anchors.

So obviously, sleep wake time being one of those really important anchors, how to think about that in the context of night shift. and we can just reverse that and apply that to other folks who are sleeping nocturnally and then exercise and maybe in meals too because I think those are you know those these are the levers that people can pull to kind of mitigate the effects and really get themselves in a position where their body is is primed to actually sleep and get the quality sleep that you're talking about yes I love the set the last one about exercise and meals because I have some differences of opinion based on what the current literature oh gosh I can't wait to But I will talk about that after I talk about sleep and wake time.

Beautiful. So the biggest thing to just getting restorative sleep is consistent sleep and wake time. So whether you're a shift worker or a day worker, sleep and wake time, the time you go to bed and the time you wake up needs to be consistent. And the reason for that is that is optimizing the circadian rhythms. So we have the biological blocks of the body. There's one in every single organ. I was fortunate enough to be a part of the team who discovered the one in the skeletal muscle. So even our skeletal muscle has a circadian clock that directly manipulates how quickly we get

into restorative sleep. Sleep and wake time has to be consistent if you want restorative sleep. We know that from tons of literature in humans and mice and using genetic manipulation, like everything. We've seen that too just in the research that we're doing kind of internally. and the one that we did with the Army Alaska, very evident. You know, we had 1,000 paratroopers, and we're, you know, I'm still working on analyzing all this data. But, but it was, yeah, I mean, it was incredible to see the relationship between individuals who had stable sleep wake time

and their perception of control over their lives, their perception of just their own resilience, sleepway time was just something that folks need to, it's just a behavior that, you know, it can, obviously, as you're saying, affects every, every cell in the body, every clock in the body yeah and we have the opportunities now like whoop with the sleep coaching platform it will tell you like oh you should start going to bed you know like it's you know there's really no excuse now because we all mostly have our phones even even operators in austere environments they still have their phones um and so the other thing is exercise and meals okay so i've been fortunate enough to be review a reviewer for a lot of the studies that have come out recently. I feel like this is going to be epic right now. I'm like, I cannot wait to hear what you're going to say. Well, it just goes to show like what happens when you stay in your

foxhole and you don't cross-collaborate with exercise physiologists. Oh my. Thank you for saying that. Yes. Yeah. So, and I'm not an exercise physiologist, but I'm an athlete and I've been an athlete my entire life. And I know if I work out too soon before I go to bed, like there's one time the Brose came to Fort Knox to film one of the open workouts. And like, we did the open workout at like nine at night. I did not sleep at all that night because I was just wired. Yeah. I'm the same. I cannot work out at night. I really struggle. I'll just, I'll lay in bed for hours. And we know this from elite athletes like hockey players. Hockey players have a tremendously difficult time falling asleep. I've done a little bit of work with the Washington Capitals and all of them.

that is the biggest complaint as hockey players is I cannot fall asleep after a game. My son plays ice hockey and they, you know, he's in high school. He's a freshman playing varsity. And like literally their ice hockey times are just, they make me so angry. Like he doesn't get home until like 10.30. But what I did in his bathroom where he takes a shower is I put a super dim light in a shower. So like once he gets home, like lights are super dim. He goes in his bathroom.

It's super dim. So that actually has helped him. I saw a big difference for him. Yeah, yeah. But just when you're working with people, like that, people don't realize the impact of light when they get into their home environment and how that just either keeps you on that path to be alert or not any light into the retina is going to, you know, tell your body to be awake. So yeah, that's had a huge impact. And he's been able to fall asleep much faster as a result. That is so awesome. I might actually, I'm going to give you credit, but like when I continue to work with the capitals, I'm going to take it. Tell them to get their luck. They're going to win another Stanley Cup because of that. No. Love it.

But, okay, so the issue is, is I read these studies, and they never, not a single study that says, oh, you know, exercise an hour before sleep doesn't actually impede sleep. It's because not a single study gets the rate of perceived exertion above 50%. Yep. And I'm like, there is your problem right there. It's because even if they are untrained athletes, 50% is just like taking your dog for a walk. before you go to bed. Yep. Like, you're never going to disrupt sleep because you never exceed 50%.

And so, like, I have yet to see the dose response curve because I guarantee, I don't have the money or the, like, bandwidth to do it. But as soon as that one research does the dose response curve, you will see sleep disruption. If they're looking to kind of have their system anchor to exercise, what would be your recommendation for individuals just generally? So three to four hours before your bedtime. So the people who are doing like the late night CrossFit classes, like the 7 p.m. That finishes at 8, they're cutting it close, especially if their bedtime is around 10 or 1030.

Because after they go to class, they're not going to bed. They're going to go home and eat, which can further disrupt their sleep because if they're eating things high in the glycemic index, that can delay. their amount of time in restorative sleep. Yeah, so those blood sugar spikes, yeah, we'll end up fragmenting. So, and again, it might not impact sleep onset time, but they will show up in disturbances and your point time in deeper, these deeper stages. Yeah. So meal timing, you know, and I know you think about intermittent fasting or time restricted

feeding and how that relates to your circadian clock, how do folks who are working at night, you know, or sleeping at night, you know, how do we think about time restricted feeding, kind of what are the best practices there in terms of really helping us fall asleep when we want to fall asleep and stay in deeper stages of sleep. So I will say I'm not as much of an expert in like time restricted feeding and circadian rhythms. I do know there is a very close relationship and intermittent fasting is one of those things that further makes the circadian clock be best to optimize. But I think the biggest takeaway is to make sure that if you are an athlete and you need to eat something before you go to bed because you don't want to wake up

in the middle of the night starving is the worst feeling in the world like during crossfit training season worst feeling ever is to wake up hungry but make sure you're sticking to a low glycemic food so that you don't have the sleep disruption or sleep fragmentation because of spikes in blood sugar so food that's bioavable high fat you know yogurt cottage cheese which has a dual benefit of being high in case in protein, which kind of you've seen in the research kind of helps with the recovery process. But we just don't want it. We don't want your body having to work hard to digest when you're trying to sleep. Both are parasynthetic activities. Your system is going to bias toward digestion, obviously, as opposed to sleep. So I think that we see this very, very

clearly in the data, and we're just hypothesizing that that's kind of the dynamic or the phenomenon going on. And we actually have a big study with five different schools, seven 100 female athletes, and we're looking at pre-sleep feeding and how it impacts all sorts of factors that we, you know, the metrics that we track. So it's been interesting to kind of see some of those dynamics play out in that population. Oh, that's awesome here, because that's exactly what we need is like, I mean, that's what I love about what you're doing, Kirsten, and then, like, the whole WOOP team is like you're taking the, like, the big data approach and working with tapping into some of the hardest-to-reach demographics.

Yeah, yeah, with huge amounts of logitula data. It's been great. These are questions, you know, that are related to human performance that, you know, if we can get some answers to, just we can just further drive these, you know, optimal behaviors that are going to help us do the foundational things that, you know, set us on a path that lead the richest, healthiest life, you know, possible. And I think some of these things sound kind of trivial like, oh, well, stopping eating, you know, three to four hours before bed, like, what really I need to do that?

but it is the difference between potentially living five to 10 years longer. Like it's like it's actually not trivial when you think about your lifespan. And I don't want to be an alarmist or, you know, kind of overreach here. But I think that these behaviors actually add up in a profound way and impact our system. And I think, you know, back to our original point here on this theme is that if we can do some of these very simple things related to light, you know, fueling, exercise timing and sleep wake timing, we set our system up. up to be just a more effective efficient system or machine, and, you know, which then, you know, protects us potentially from a lot of these disease states. So maybe let's like just talk briefly about, you know, maybe the top three, you know, strategies and tools folks can do during the day

to either kind of make up for insufficient sleep or sleep debt. You know, what are the things that they do today that kind of mimic that? So, you know, maybe naps, yoga, need your breathing. You know, we can kind of hit on your point of view on the top of the top few yeah so number one napping we have tons of data for that now in athletes military you name it mapping is a wonderful thing um two if you can't nap something like yoga medra this guided meditation practice to try to get some level of asleep like you might not hit the deeper stages like you do at napping but you might hit the later stages, and so that is a means too. And then the last one, it seems counterintuitive. So it's more of like short-term acute sympathetic activation for long-term parasympathetic activation is heat exposure

or cold exposure. I personally, so we did a small case study, a small longitudinal case study with elite CrossFit athletes when I was at Emory doing my fellowship. And we actually found that cryotherapy, so that like two-minute bolus of cold exposure actually has prolonged parasympathetic effects. And it actually increases self-reported sleep quality and also a total sleep time, independently of days of training, time of training. And it, again, it was a small sample size, but it was longitudinal. So I think that's also a good thing, too, is heat or cold exposure. Yeah, I love that you said that. Like, I think there's seems to be more and more studies coming out to support that. And in fact, I think there seems to be

a protocol that validated in some recent research that came out in cell in 2021, but basically says that about 11, 12 minutes of cold exposure per week in, you know, two to three minute increments, you know, four times a week is kind of the protocol. And they say, you know, just be in the, you know, the temperature is basically whatever you feel is like uncomfortable and you want to get out, just stay in there for a couple minutes, do that a few times a week, and, you know, you'll see improvements in sleep, and then there has a downstream effect to, you know, improving immunity. And, you know, I think given, well, it's, you know, short-term sympathetic, it's, to your point, it's got this parasympathetic kind of longer-term effect that is super powerful in reducing,

or just making you more resilient and more robust. Let's see, we've got, we tapped naps, yoga nidra, maybe just breathwork as kind of a final strategy or tool folks can engage in. Yeah, so I have used the box method, and I've also used the Wimhoff technique. I really like the Wimhoff technique because, you know, there's a lot more evidence-based for breathwork now, but his work was kind of the first to, like, make it big time. I mean, his study ended up in the proceedings of the National Academy of Sciences. So you can't do much better than that.

But, you know, similar to cryotherapy, like the Wimhoff method, it's acute sympathetic activation for long-term. and parasympathetic responsiveness. The box method, as you know, like parasympathetic activation. But that's really what it comes down to is whether or not something's going to keep you or prevent you from getting quality sleep

or not getting quality sleep. It's the amount of sympathetic versus parasympathetic activation in the day. And if you could pair the two, then that's awesome. And breathwork is a great way to, like, voluntarily induce parasympathetic activation. Yeah, and I think, you know, I say this over and over, you know, to whoop, ice script for the rooftops every single day with my colleagues as we try to, like, develop features and give folks access to some of these tools inside our app.

But, you know, I think that they're understanding that we have way more control over our autonomic health than we think we do, you know, and I think at the end of the day, you know, I think our mission at whoop is to help people understand their physiology, help them take control of their body in a way that gives them, you know, agency over their health. And I think one of the things that, you know, people can use the whoop out for is just literally understanding, okay, I might not have the sleep that I need that night. That means I'm going to be inherently more activated today. Like my cortisol levels are going to be higher. I'm going to be, my system is not going to be working as effectively. but I can mitigate the effect of that with my breathwork, with yoga nidra, with potentially taking a nap.

Like I can offset the deleterious effects of maybe not getting the sleep that I need and actually build a healthier lifestyle that will actually help me get the sleep that I need in the future. You know, start to unwind maybe some of these vicious, you know, negative cycles that occur when we're not getting enough sleep. And taking control of the behaviors when you're awake is to me the shortest path to kind of helping, improve your your sleep at night. 100%. All right. Let's talk a little bit about culture, despite, I think, a lot of education around sleep. And I think people are intellectually, rationally understand, wow, okay, I need to spend

more time in bed. But maybe just talk about the rise of sleep debt. You know, we see this in the data. And it's broader implications on society and culture. And, you know, what are some strategies or ways that leaders can think about their organization to really try to shift this mind. mindset mentality. So I think the biggest thing about leaders is presenting them with the objective data to show otherwise that like prioritizing people's time for sleep, not just at home,

but napping at work is the way to go. We actually have that, I love telling the story in the Army. We have that big success because I obviously work for the most anti-sleep promoting organization of them all. Like it's better now, but it's still bad. And so a few years ago, we wanted to get sleeping pods at Walter Reed for the residents and the night shift workers. And at first, it was like met with the ultimate amount of criticism. So much so that I'm actually surprised I still have a job because of this is we took anonymous quotes from senior leaders that said they didn't want soldiers napping on the job. If they did, it meant they were lazy. you know, only lazy people have time for naps.

And so we took those quotes and we put evidence refuting those quotes and published it in the flagship journal of sleep as a letter to the editor. That's bold. And sure enough now, Walter Reed has napping pots. Oh, that is such a success story. Unfortunately, you have to be, I mean, I know that's actually my job in the Army is I'm the person. that I think senior leaders hate because I tell them, no, like, sleep is important and I, you know, prevent them from doing more. But that's exactly what society needs is we need this cultural shift towards sleep. Allison, thank you so much for all your time today. I think this has been,

you know, an incredible discussion. And I just, it's just been an honor to kind of be able to ask you questions and tap into all of your expertise across these domains. And Justin, thank you for your being a part of our women's performance collective as well. I think there's going to be an opportunity to do some really cool research with that group just around women's health and reproductive health and kind of that spectrum. So excited to kind of tap you for some of that work as well. Oh yeah. I mean, you are doing an incredible work personally. I appreciate that so much. Yeah, we're excited about it. And yeah, but it's only possible with, you know, collaborators like yourself. And honestly, the foundational work that you've done in this space, frankly, you know,

as it relates to sleep, you know, is really inspired a lot of the ways we think about, you know, our data sets and what we can, you know, kind of look into, like, more deeply. And, yeah, just so appreciative. So, thank you. Thank you to Dr. Breger and Kristen for coming on the WOOP podcast. If you enjoyed it, please don't forget to subscribe, leave us a rating. Don't forget you can use the code will, W-I-L-L, get 15% off a W-W-M membership. check us out on social at Woot, at Will Ahmed, wishing you a very green week.

We'll be back next week. Stay healthy. Stay in the green.