Ten Percent Happier with Dan Harris - The Science of Sleep: Why You're up at 3AM — And Why Worrying About It Makes It Worse | Sara Mednick

Episode Date: May 13, 2026

Sara Mednick is a cognitive neuroscientist at the University of California, Irvine, and the author of the book The Power of the Downstate. This episode is part of our month-long "Mental Health Reboot" series to mark Mental Health Awareness Month.  This episode is from our archives. In this episode we talk about: The nuances of napping Dr. Mednick's definition of the "downstate" Whether there are practices that can compensate for poor sleep Why heart rate variability is an important measurement of health Why sex is so helpful for sleep And when to take melatonin to best effect Join Dan and Emmy Award-winning journalist Allison Gilbert at 92NY on May 17th for a live conversation about how mindfulness can deepen connection and combat loneliness, available in person and via streaming. Register here. Join Dan, Sebene Selassie, and Jeff Warren for Meditation Party, a 3-day immersive retreat at the Omega Institute in Rhinebeck, NY, October 16–18. Grab your in-person spot here, or sign up to livestream here! Get the 10% with Dan Harris app here Sign up for Dan's free newsletter here Follow Dan on social: Instagram, TikTok Subscribe to our YouTube Channel This episode is sponsored by: Rosetta Stone — Language learning that's immersive and intuitive. Ten Percent Happier listeners get 20% off a Rosetta Stone Sapphire subscription at https://www.rosettastone.com/happier Quo — The business communication system built so you never miss a call. Try free and get 20% off your first six months at https://www.quo.com/happier To advertise on the show, contact [e-mail] or visit https://advertising.libsyn.com/10HappierwithDanHarris

This is the 10% Happier Podcast. I'm Dan Harris. Hello, my fellow suffering beings, how are we doing today? If you are interested in getting more and better sleep, there may be a temptation to think about it as strictly a nighttime endeavor. However, my guest today says you cannot think about improving your sleep just in the minutes before you go to bed. Her neuroscientific research has led her to conclude that we need to think about sleep more holistically. and as just one of the body's ways of resting and restoring. Dr. Sarah Mednick is a cognitive neuroscientist at the University of California, Irvine. She's also written a book called The Power of the Downstate. In this conversation, we talk about what the downstate is, the nuances of napping, what the science says about who should and should not take naps, whether there are practices that can compensate for a bad night's sleep,

why heart rate variability is an important measure of your health, why sex is so helpful for sleep, when and how and whether to take melatonin, and much more. Just to say, I first did this interview way back in 2022, but I'm pulling it out of the archives today because we are in the middle of what we in the 10% happier cinematic universe are calling sleep week. Specifically over on the 10% app, we've just added 10%. and new sleep meditations. Sleep really is the apex predator of healthy habits.

Nothing works without it. So if you want to get all of this new content, and by the way, get this podcast without any ads, you can head on over to Dan Harris.com to sign up. Also, if you know anybody who could use some meditation or a little sleep, you can now give the gift of a subscription to the 10% app. Just send an email to support at danharris.com with the subject line gift,

and we'll tell you how to do it. Oh, one more thing. One more thing while I'm plugging here. If you happen to be in New York City on May 17th, I'm going to do a live event at the 92nd Street Y. A guided meditation, take your questions. It's going to be really fun. Link in the show notes to get your tickets. All right. We'll get started with Dr. Sarah Mednick right after this. If your team's communication is messy, your customers feel it. Missed messages, drop threads, slow replies. It's one of the easiest ways to lose momentum and lose customers. That's why today's episode. is brought to you by Quo, spelled QUO, the business communication system built so you never miss a call. Your entire team can handle calls and texts from one shared number, so no more missed messages or drop conversations. Everybody sees the full thread, replies are faster, and customers actually feel taken care of. Quo works wherever you are right from your phone or computer. Keep your existing number, add teammates and minutes, sync your CRM, and let your call routing handle itself as you scale. On my team, we take the customer experience really seriously, and if you're a small business owner,

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visit rosettastone.com slash happier to redeem your 20% off. That's rosettastone.com slash happier and start learning a language for real. Dr. Sarah Mendek, welcome to the show. Thanks very much for having me. It's a pleasure. I'd be curious to start with a little bit of backstory

from you about how and why you got interested in sleep. Well, there's a long story and a short story, and I think I'll stick with the short story, which is that I got into the Harvard graduate PhD program to work with one person, and that person turned out to not be a good person for me to work with. And I had to leave her lab and go to a new lab that accepted me, but they were doing vision research, and I didn't really understand really what kind of vision research they were doing, but I knew I had to suddenly start doing vision research. But I had to suddenly start doing vision research. but I happened to sit through a lecture by a guy named Robert Stickgold, and he had just begun doing research in sleep and memory. He was the first person to truly put together the experimental

methods that we use today to understand how sleep affects memory. And he was showing all sorts of strong results about different sleep stages, affecting different memory processing, but he was doing it in a nighttime, a full night of sleep. And so I contacted him and said, hey, I do vision research, and you're kind of doing vision research, but with sleep, how about if we work together? So I was at the vision lab at Harvard, and they let me change the copy room into a little sleep lab.

And I got a cot from the Harvard dorms, and I got a bunch of sheets from the Salvation Army and a little portable EEG system, and I started doing nap research for multiple reasons. One was that I didn't want to sit through watching people sleep, a full night of sleep while I had to just sit there and watch them sleep. That seemed really like a bad idea. But also because all of obstacle work was about nighttime sleep and showing that you needed around eight hours of sleep to really get any benefits of sleep. And I thought, well, that's weird because I know a lot of people, my dad included, that were really avid nappers, and they got a lot out of sleep,

and they woke up feeling great. So why don't we try to do the same exact studies that he was doing, but then put them in a nap design? And surprisingly, we showed these really strong effects where the same magnitude of benefit that Bob was showing with a full night of sleep for memory results, memory performance, we found the same magnitude with nap results. And The second paper we published was a nap is as good as a night for perceptual learning. And that sort of started my career, really, looking at sleep, but specifically using naps as a tool. It's interesting we got to naps pretty quickly because I've heard that napping can be problematic because it could mean that you have more trouble falling asleep that night because you've

reduced, I believe the technical term is your sleep drive. And so I have a lot of trouble sleeping and have tried to stay away from naps, even though I love them, because I don't want to mess up the coming evening. Yeah, I think that you sound like you've been talking to all the reviewers I've ever had in my scientific journals. A lot of sleep scientists who are clinicians really don't believe that naps are good because usually these people are talking to people who have real insomnia problems. And so one of the main treatments is to restrict sleeping to a very short period of time in the middle of the night and definitely not allow sleeping in the middle of the day. And then hopefully that will train your system to just sleep at night. And I think that for people with severe insomnia, that really is a helpful practice because it just trains your body that you're so exhausted that you just sleep at night. Now, about 50% of the population sound like they're actually like you, that they enjoy naps and they get a lot out of napping.

And when they nap, they don't actually have sleep problems at night. I've done a bunch of research looking at nappers and non-nappers. And it turns out that people who are nappers and non-nappers don't really have a big difference in their nighttime sleep. And that people who are nappers have the ability to get into sleep, stay there, and enjoy their sleep. but wake up feeling really refreshed and stay in kind of lighter sleep. So when they wake up, they're not feeling that heavy sleep inertia that people who hate naps often feel because they wake up and they feel like crap. So I think that there's a lot of nuance to the question of are naps good for you? Should you nap? Depends on a lot of questions about what is your intention to nap.

I don't know if you saw this recent study that came out, I think, last week, where they were showing that napping habits can predict increased risk for dimensioned Alzheimer's. And so, of course, I was asked to comment on this finding. And the truth is that a lot of these studies don't really separate why people are napping. And when we get older, we have muted circadian rhythm signals, our arousal signals are actually dampened. And so people start to accidentally fall asleep in the middle of the day. And then there's people who are nappers who just like, I take a nap every day, I take a nap three times a week, this is the time, I take a 20 minute nap, I'm in, I'm out, I feel great, no problem sleeping at night.

So when you're doing these sort of epidemiology studies, a lot of the time people don't separate the different reasons why people nap. And what you find is that the people who are napping because it feels good, they feel smarter, they have better emotion regulation, they get lumped in with the people who are actually having some comorbidities and sort of pathologies that are just starting to show by this accidental napping during the day. So I think it's a complicated question about whether it's a good idea to nap because I think for some people it isn't and you should not nap, but for other people it's great and it can save your life. Complicated, but you distilled it, I think, quite nicely.

The answer depends on what's going on with you and how your body is and how your system is, and that makes a lot of sense. You use a term that I want to get into the downstate, and I'm curious what you mean by the downstate and where does sleep fit into that? Yeah, that's a great question. So when I started doing the nap research,

We were in the very primitive stages of this field of sleep and memory. People have been setting sleep for a long time, but this particular field of sleep and memory, and sleep in general had been pretty primitive in terms of just looking at minutes of sleep, minutes of slow-wave sleep, minutes of REM sleep. And what we found in the next 15 years was this massive technological advancement in all of neuroscience. And the way that that got passed down to sleep is that we started using more engineering type of tool. like signal processing tools to start doing more sophisticated analysis of the EEG. And what we found were these things called slow waves.

And slow waves turn out to be the strongest indicator for the most restorative part of your sleep. They are the time where you're in your deepest sleep, and they basically have an upstate and a downstate. They're one second long, and you go through a period where all of the neurons start firing in the upstate, and then bam, everything silences in the downstate. state. And you see the entire brain go through these waves of all the neurons firing together, and then all the neurons basically go brain did. And these slow waves turned out to be very important for all of those things that we know our sleep are important for. Memory, restorative

processes, growth hormone increases, decreases in cortisol, but also then the glymphatic system, right, this whole new research showing that during deep slow waves sleep, you have these waves of liquid that are washing your brain, all of the toxins that build up across the day with increased neural transmission, you get these proteins that need to get washed out of your brain every night because if they don't, they build these plaques. And those plaques later become, especially with dimensioned Alzheimer's. So these slow waves obviously became sort of a sense of central feature of sleep research. And that made me, you know, think about this idea of upstates and downstates. And then I started doing research in my lab on not just the brain, but also the

autonomic nervous system. And I started looking at the relationship between the parasympathetic nervous system, which is that rest and digest, and the sympathetic nervous system, which is the fighter flight. And I know that when we're awake, we have very high sympathetic arousal, which in my book I call rev, that you rev really high during the day. And when you go to sleep, you have very strong parasympathetic response to that high rev. And I call that restore. So you have you're revving during the day and you have this strong restorative system during the night. And that's when the light bulb started to go on that it seemed like this idea of having rhythms where nature creates this time for energetic output,

and then a very concerted effort to have a time for a restorative downstate where you can restore all of the energy and nutrients that the previous upstate used up and get yourself ready for the next upstate, that that turned out to be a central principle of all of our biological systems. And that's when the book idea, came to me is to really say, well, why don't I tie all these ideas together? Because you can see upstates and downstates in exercise, in nutrition, in sleep, and circadian rhythms, in our autonomic nervous system, and in fact, conceiving of yourself as being rhythmic and having these ideal times

for output and ideal times for prioritizing restorative processes actually is the most natural way to live and the healthiest way to live. And that's where the downstate really came to be. It started with sleep and then it kind of mushroomed. So the downstate, if I understand you correctly, is a broad term that encompasses all of the ways in which our body naturally relaxes, inclusive of sleep. That's right. Yeah. I mean, I think that one of the things to think about is that we are not a bunch of separate systems that are disconnected from each other, that all of our little subsystems, you know, the cardiovascular system, the metabolic system, the sleep system, our muscular system, everything needs a downstate. And you can think about them

as individual downstates that all day long your heart is pumping blood against gravity to make sure you have enough nutrient-rich blood in your system, and then you need to give it some breaks. And the most natural break that you can give it is during sleep, because this is when nature has forced you to go into this deep sleep relaxation state that is a huge break for your heart. It's called a cardiovascular holiday, actually, slow-wave sleep is. But there's also downstates that occur outside of sleep that you can actually decide to engage with, right? You know, slow, deep breathing is a down state that you can create for your heart to get it into a deep, relaxed state and to cool down rev and turn up, restore processes. And doing inversion poses

just like lying on your back with the legs up the wall or just having your heart lower than your hips and your legs for just 10 minutes a day can have very similar effects because that turns down Rev and turns on restore. Definitely sleep is the way in which most animals use to flip that balance between your upstates and downstates. But as you know, with your own sleep problems, there's many of us that don't sleep as well as we would like. And so the question is, how can we also bring these downstates into our daytime and really intentionally make time for restorative processes. We're going to talk about the downstate generally in this conversation. But now that we're talking about people with sleep problems, I think one psychology that I find myself slipping into,

and I suspect I'm not alone in this, is I get freaked out because I see all the data that show that if you don't sleep, well, you're susceptible to all kinds of terrible diseases. So I guess when I hear you talking about the downstate generally and sleep as a part of it and the notion that we can have other practices that would help us get into this rhythm that allows us to perform at our best. I'm just wondering, do these other practices inversion, deep breathing truly compensate for poor sleep? Obviously, there's a lot of different places that poor sleep can be coming from, right? There can be levels of over-arousal. You know, one of the strong, strongest ways to prevent yourself from getting into sleep is being worried that you can't get to

sleep, right? So the common problem is that people start obsessing over the thought of, I won't be able to get to sleep tonight, and lo and behold, the worry prevents them from getting to sleep at night. So there's psychological and anatomical, physiological problems that can contribute to poor sleep. I think that one of the things that's important also to think about is that sleep doesn't work on its own, right? So sleep isn't just its own. So sleep isn't just its own thing that if you just think about your sleep, that's going to solve all your problems. What you do during the day and all of the ways in which you're leading yourself up to the point of getting to bed and going to sleep is directly contributing to how well you're going to get

to sleep. So it's not just that one hour before bed that matters. It's what time did you exercise that day, right? Did you exercise? And what time of day did you exercise? Because exercise is a huge increase in rev sympathetic arousal. And if you are somebody who exercises later in the evening, you're going to have a very hard time getting your rev system to calm down and allow the restore system to take over and bring on that deep sleep. If you are someone who is eating later and later in the evening, eating later in the evening is going to delay your melatonin onset.

melatonin is a circadian hormone that helps you tell when it's time to decrease your arousal and go into sleep mode. What you're doing during the day and these kind of rhythms of how deep you're breathing, how much you're relaxing, how much you're spending time away from the desk, taking a walk, having an intimate conversation with somebody or a hug, something that calms you down during the day. If you don't do those things during the day, you just have an increased system. that is just sort of increasing potentiation, right? Increasing its stress. So by the end of the day, it's quite difficult to really get to the place where you can calm down enough. So if you think about your day as part of the whole picture, if the main goal is to get good sleep, then think about how you're

eating. Think about how you're breathing during the day. Think about how stressed you are. think about what time and what kind of exercise you're getting. And that has a huge contribution that I think we don't often think about because we think of these things as kind of siloed. It's a really good point that we need to take a holistic approach to sleep that is more than the 15 minutes leading up to bedtime. It's how are you living? The rest of your life can really have a direct bearing on whether you're able to fall asleep and the quality of that sleep. But I didn't hear you address whether some of these other downstate practices can make up for poor sleep. It sounds, I'm just going to guess that maybe not. I mean, that's a good question,

right? So if you had really crappy sleep but you were doing everything else, would there be some sort of a balance there? Would you be able to stay in the right ratio of upstates and downstates if you did everything during the day but still had crappy sleep at night? I don't know if we really know the answer to that. I mean, I think it's really hard to say that that would still be true, right, that if you really were taking care of yourself during the day, that your sleep would still be really bad. And taking care of yourself also means treating all the medical issues around that are preventing you from sleeping well. Sleep is golden. Sleep is a very important part of the system cleaning itself and the system making connections and memorizing and regulating our emotions, all those things.

But there is also evidence to say that it's not necessarily the slow wave itself. The slow wave is really the most optimal time for all this restorative stuff to happen. But there's a recent study was looking at the lymphatic clearance question and saying it actually looks like it's the autonomic nervous system that is running the shorthy. in terms of the glymphatic clearance, and that just happens to usually occur during deep sleep. But you can find ways to dissociate these things and see actually deep parasympathetic activity, vagal activity, is really very important for this kind of, you know, cleaning out the toxins. And so is it possible? We don't really know, but is it possible that we could shift some of the burden

off of sleep to do things that most animals just need to regulate getting to sleep, right? Because then they just go to sleep and they stay asleep. But for us, because we have these ways of which we really have problems sleeping, maybe there's ways that we could shift the burden to daytime. You used a few scientific terms of art there. So let me see if I can restate it in a way that clarifies it for people. There's this brainwashing in a positive sense that happens. when we're a deep sleep where the toxins get washed out,

and you're musing aloud about whether perhaps other downstate practices or practices that activate the parasympathetic nervous system, or I think you use the term Vegas nerve, we've talked about that before on the show, whether activating the parasympathetic nervous system and the vagus nerve can actually put us in a state where we're doing the brain washing when we're not, sleeping. Do I have that roughly correct? That's really exactly right. And the thing is there is a lot of

research that's conducted during wake on people who are improving, say, their heart rate variability. Right. So heart rate variability is a really key concept when you're talking about the parasympathetic restore system. So the restore system is basically doing everything to make sure that your body is ready for whatever comes. So both the REV and the Restore, the sympathetic and parasympathetic, I call them REV and Restore. They're reacting to the environment and then they're calming you down. So it's the proverbial tiger in the jungle that if you, is that a tiger? Suddenly your heart races, sending nutrient-rich blood to all of your muscles and away from digestive systems and all different other non-necessary systems to make sure you can bolt out of there if they're

actually is a tiger. And when you suddenly realized, oh, no, that's just a bird or a domesticated cat, you need something that's going to calm you right down. And that's the restore system, right? So you want to rev up and immediately calm down. You don't want to stay at that hyper aroused level with your heart pumping needlessly because it takes a lot of energy. So when we talk about heart rate variability, what we're talking about is the variability between your heartbeats. And when you have a high variability, that means that your system is very good at speeding up your heart rate when you need to and slowing it down right when you don't, right, when you need to calm down. So high variability means that you have a very strong restore parasympathetic system that can calm you down very quickly. You stop running and suddenly you're back to normal, right?

People with low heart rate variability are people that have their heart rate set either very low. and so when they need to activate, they can't get their heart rates pumping very fast. Or once their heart rate starts pumping, they just stay super fast, and they stay in that overly stressed state for too long. So that system can be trained. You can increase your heart rate variability. You can do that through many different parasympathetic practices, such as slow, deep breathing, meditation, yoga.

These are all practices that include deep, slow breathing, with every movement. You can also do it with heart rate variability biofeedback, where you actually use a system that is basically helping you figure out how to slow your breathing down, how to calm yourself down. And the more you do that, the more you see the same benefits as you see with sleep, which is better executive functioning, right? Better attention, working memory, inhibitory, processing all these kind of strong frontal lobe functions. And it's bidirectional, right? So you can increase your heart rate variability and see these benefits that you usually see with sleep. And you could also do all these working memory training tasks that people are constantly doing now as

they get older brain training games. And that also increases your heart rate variability because your brain and your body are connected. And yes, this natural process does happen during sleep as well, but there's online waking experiences that do create similar effects. I apologize if there's obtuseness woven deeply into this question. Can you draw the connection between heart rate variability and sleep? Yes. So the heart rate variability is your ability to calm yourself down.

It's your ability to calm down your heart rate. That system is controlled by your parasympathetic restore system. So when you go to sleep, because you've been spending your whole day in this high arousal, high sympathetic rev state, the natural upstate, downstate pattern is that sleep is the domain of parasympathetic activity. So right when you go to sleep, you see this massive increase in heart rate variability. You see this very strong, basically the brain is doing a lot of restorative work. And you see this effect of increasing heart rate variability from waking to sleep. That's because the sleep system is very restorative.

So it helps activate the restore system. So people who sleep well have high heart rate variability. Got it. And it seems like given the important. of heart rate variability, even if you're not sleeping well, which obviously that should be treated, there are other ways to improve it. Absolutely. Absolutely. Coming up, Dr. Mednick talks about when to exercise for optimal sleep and the benefits of getting outside in the morning. Let me go back to a few nuggets you dropped along the way. One of them is this freak out that happens nightly

for people like me who have trouble sleeping. I believe the term is orthorexia, which is is you start worrying about the quality of your sleep just when you're trying to fall asleep, which prevents you from falling asleep. Asking for a friend here, what do you recommend in moments like that? I mean, there's so many things that people can do. I want to just kind of take a macro look at it before I get into sort of, here's this trick. I think the macro view is that our brains, they're habitual machines, right? They're looking for consistent schedules. They're looking for ways to create habits. I have a friend who I talk about in the book, Carlos, who is a big guy in some energy corporation, and he had a horrible problem with sleep.

And he was in this situation where he was doing international flying, and he would have to take these middle of the night flights and wake up really early and then take this flight. And basically his brain learned that, oh, at 3 a.m., I need to wake up because I need to catch a flight, right? That's what you keep doing. so now I'm going to set it up for you. Great. It's 3 a.m. Let's wake up. And he went to many sleep doctors, and they had him doing the sleep restriction that we talked about before, and all sorts of kind of sleep hygiene changes.

And for him, there was something that was beyond just, you know, making small changes. He had created a whole sort of conditioning around his bedroom, his family, his son that would wake up in the middle of the night when he was a baby and everything suddenly became this reminder for him to wake up at 3 a.m. Because that's what our brains are looking for. They're looking for consistent patterns. And it actually took something much larger to change his sort of conditioning. And it took the pandemic, which is that he basically didn't have to travel anymore. He moved to a different house and he started exercising every morning, 30 minutes in the pool. And his sleep, problems completely went away. It was like night and day. So I use that example to say that we think about

these kind of sleep problems as being things that are, what's the quick fix? What's the biohack? This kind of quick and dirty way to change a pattern. And sometimes those quick and dirty things do work. I think sleep hygiene is very powerful. I think that listening to what sleep doctors say is very important. But I think sometimes there are patterns. that we've learned that we need to actually take a look at and say, what can I do to really reverse something that has been sort of set like a groove in a record that has been set and jump that groove. So the macro answer is let's look at the reminders and the patterns that have developed that make it such that when you get into that bed, you start worrying, right? What can be changed there? And then let's get into also all of

the details, right? Get into sort of what can we do? If you're lying there, you know, get out of bed and there's a practice of writing. Write down everything that you are concerned about, write down everything that you are thinking about and worrying about, and right until you're tired. And eventually something will shift and you'll get to a place where there's nothing else I can say, I'm really tired, I'm going to go to bed. There's all sorts of gratitude practices that bring your mind away from this impending drama with your nighttime, like write down 10 things that happen today that you feel really grateful for. Shift the whole focus of your mental state into a state of happiness, gratitude, and open-heartedness. That's a very powerful trick of the mind. And I also

find that finding a book that is very dense and that you can find yourself really trying to read and it's a little beyond your capacity at the moment, like a good history novel, maybe something with a little bit of math in it or something that is a little engineering or something of that kind, something that will make your mind just kind of poop out. You have to listen to your patterns, right? You have to feel that the second you start to get tired, and that probably happens way before you get into bed, right? The second you start to really feel that drowsy feeling, it could be at 9 p.m. and you think, what's wrong with me? I feel so lame for falling asleep at 9 p.m. But the second you feel that sleepiness, stop whatever you're doing and go to sleep. And the second

you're reading, you know, Wolf Hall or whatever it is that is driving you to drows, close the book, turn off a light, and let it take you. There are many things we're advising people to do often on this show. One of them is, you know, you should get a good night's sleep. We also talk a lot about meditation. But a third of many is the relationships in your life are really important and you should be deliberate about making and maintaining friendships. I'm going out with my wife tonight to go see a concert with some friends.

we're probably not going to get home until 12 or 1. We usually go to bed at 11 or 1030. So is that on wise or is that like an okay tradeoff? Or what's your take on this? Well, I think, you know, it really depends on the person. So I think that any time that you get super regimented about anything, fanaticism is liable to lead to some problems. So anytime that you freak out about But if you're doing time-restricted eating and you suddenly have to go out to dinner and it doesn't fit in your schedule, let it go. You know, just eat and enjoy yourself and be part of the world. And the same thing goes for sleep, right?

So I would say we need to be really mindful of the fact that we are habitual animals and our brains have little clocks in them. Every cell has a little clock and it's looking for you to do the same thing twice in a row, three times in a row, four times in a row, and say like, oh, good, a pattern. Okay, I will set up everything to abide by that. And that's why sticking with upstates and downstates that are natural rhythms are really important, because then you set yourself up to have your metabolic system be at its prime for all the food that you're going to give it, right? And then when you stick with having a window of time where you're eating and then a long window of time where you're not eating,

then your body can do all this deeply restorative stuff and not suddenly get this burst of sympathetic activity when you start eating and just destroy all the restorative stuff that you were doing. The same thing goes for sleep. This is why people who take naps every day, they get tired every day before they're supposed to take a nap because their bodies tell them, you know, for the past 10 years, you've been taking a nap at this time. And if you suddenly move into a situation where you can't take a nap, it's really hard on your system because it learns that this is when you should be sleeping. So in general, stick with a pattern. but also have fun, right?

No one single experience is going to prevent you from following your pattern, right? Even if you go on a trip and you're changing your circadian rhythm completely, you can still adjust back to your old rhythm. We're very adaptive, but we have to really also be consistent. I'm going to dilute back to a few other little breadcrumbs

you dropped along the way. You talked earlier about the timing of your exercise. So you're saying we should never work out late in the day if we can avoid it, or is there a difference between cardio and weights? And like maybe weights is okay in the afternoon, but cardio probably not great, given that it revs you up too much. Yeah, you know, once you start really getting into sophisticated kind of thinking around this, there are times in which it's best for you to do things like cardio, where your cardio workout is going to be at its peak, and that is in the midday morning time. And,

If you're doing strength training, there's a circadian rhythm that means that you're going to be strongest with weight training and with anything to do with strength in the afternoon. And this is why you see all these differences in medals, you know, one, whether the competitions in the morning or the evening. And then there's also, you know, your own circadian rhythm chronotype. Like, are you a morning person or an evening person? All these things actually, once you really get into them and you're dealing with amateur professional sports, these things really come into play because they can cut seconds, milliseconds off of your time. But just as a regular person, definitely the cardio stuff that revs you up should be done as early as possible. And the strength training

is great to have it in the afternoon. But definitely, nothing should be within, say, four hours of bedtime. Another thing to restrict as you get closer to bedtime is liquids. Can you say a little bit about that? Yeah, I mean, this is particularly true as we get older. So one of the systems that controls our urine production is our circadian rhythm. And it allows us to pee all day long and suddenly not have to pee at night. And this is very strong when we're young. But as we get older, this circadian rhythm just becomes dampen.

And that means that people who are older start to fall asleep incidentally during the day, right? and they start to have a little bit of hard time staying asleep at night. One of the things that contributes to people waking up at night is having to pee more as you get older. So there's a lot of things you can do to sort of strengthen your circadian rhythm and make sure that you're getting a lot of bright light in the morning and really pump up the arousal systems in the morning and then really monitor your nighttime systems at night in terms of light

and in terms of eating and in terms of exercise and all those things we talked about. But another way is to refrain from having liquids. Can you say a little bit more about how we can use light to support our sleep? I mean, this is something that I think is such a simple thing, and I think that we don't hear enough about it. The arousal system, which is the circadian rhythm that tells us to be aroused during the day and to be sleeping at night is the circadian rhythm. and we have sensors in our retina that detect visual information,

but they're also sensors that just detect what time of day it is by the color of light coming into the retina. And it's specifically only interested in whether there's blue light coming into your retina. And in the morning, the light that the sun is shining the morning and all day long, it's an all-spectrum light with a lot of blue light. So from dawn till before dusk, you have this very strong sun that gives you a lot of blue light, and that's basically, you know, the rooster in the morning for your brain to say, it's the morning, it's the daytime, get up, this is the time where we're going to be aroused all day long.

As the sun starts to set, the blue light decreases, and the majority of the light that you're getting in natural lighting is more orangey and red. And that absence of blue light tells your brain it's time to turn down the arousal system. And it's time to turn on melatonin. It's time to turn on all of that sleep-related systems. And so this is why exposing yourself to light early in the morning, not just light indoors, because that doesn't suffice at all unless you have like a real all-spectrum lamp that's made to really jumpstart your circadian rhythm. but just going outside early in the morning and getting real sunlight. What about standing next to a window?

Windows actually block a lot of wavelengths. So if that's what you got, great. But I would say the best thing is to just get outside. Or use an all-spectrum light because modern windows specifically are made to block a lot of wavelengths. So you definitely want to be really purposeful about this. And 15 minutes of an all-spectrum light has been shown, particularly there's a whole bunch of studies in women who have just gotten over cancer, and they have this very strong chemo effects where their sleep is super fragmented. And what they found is that 15

minutes was an all-spectrum light in the morning, improve their sleep, decrease their fragmentation, decrease the amount of sort of random arousals that they would have and increase their sleep time. So literally first thing when you wake up after you go to the bathroom, go outside? You don't want to be too freaky about it. Just be in the daytime. Don't stay indoors. You don't necessarily have to eat outside if it's the middle of winter. But definitely have that light be the important source of some time that you're spending while you're having your morning coffee or reading the paper, whatever it is. It's not enough to stay indoors in front of just regular lights. You need to have a really powerful light or just the sun. How do you control your light on the other side of the day as it becomes night without being to, I think you use the word freaky or regimented about it? There's a lot of ways that we can control the light. It's really just the blue light. There's anything from, you know, just filtering the computer screen and the evening and your phone to make sure that you have the night shift on so that it goes to completely yellow. You want to really make the shift all the way to the yellow part of the screen. and use more candlelight. Candlelight is exactly the type of light that you should be using.

That's the type that our ancestors used, right? You can buy circadian light bulbs now that change with the hours of the day. There's some really great glasses that you can buy that are yellow filter glasses, and they have been shown experimentally to help people with their sleep and with well-being during work. So I think that there's more and more understanding of the importance of regulating light, and particularly at night. Coming up, Dr. Mednick talks about sex as a way to get better sleep, the concept of skin hunger,

and why we should all be training ourselves in nose breathing. You're, from what I can tell, a big advocate of sex as a way to help you sleep. I'd love to hear more about that. You know, there's so many aspects of sex that are important. There's the aspect of sex as exercise. sex is a huge stimulator of the sympathetic rev system that you really get extremely pumped while you're having sex. And the burst of all of the rev system when you're reaching the climax is met with a massive restore response. Suddenly you become kind of incapable of speaking.

And that system is the one that is shutting the whole system down saying, oh my God, what just happened? let's go into restore mode. So this is why many people actually just fall right to sleep after they've had their climax. So just naturally, timing sex to occur right when you want to really go into sleep is actually a great way to have sex be sort of a helper for sleep onset. But also there's the whole emotional intimacy aspect of sex because just like any kind of, you know, really consensual physical touch, what that is doing, you know, just a hug, holding hands, sitting next to each other, watching a movie all the way up to sex, what that's doing is turning on your restore system. It's basically telling your Rev system, I'm okay. Look, I have somebody right next to me who I'm so close

with that they're touching me, that they're hugging me. That means that that kind of guard dog Rev, who's constantly kind of watching out for you and ready for the fight or flight response, can calm down. And even just a conversation with a friend on the phone can do that. This is not something that happens with texting or liking something on social media. It really happens with a deep connection where you feel like somebody's got my back. Somebody loves me. That is a whole system that turns on restore and increases heart rate variability and increase. And increases that downstate stuff. It's interesting that you brought that up because I was going to ask, when you were exuling

the virtues of sex in terms of helping with sleep onset, I was thinking about single people. But it sounds like one way that single people can benefit, at least in part, is to have a conversation with somebody. Absolutely. I mean, there's also just masturbation. Like, you can still have the orgasm when you're by yourself, particularly it's still exercise and it still gives you that restore response. I think the emotional connection, the feeling of safety, the feeling of not being alone, we're pack

animals. So any kind of sense of being on our own, which is why the pandemic was so hard for so many people, not only did we not see people, we didn't touch people. And there's this concept of skin hunger that after a while you actually just need to touch, you need to have some intimacy so that your brain doesn't think that you're actually all by yourself on the planet. It's not healthy. Anytime we can organically get to the subject of masturbation, that's a clear win for this show. You're handling this with a lot of patience and good humor, but I'm kind of peppering you with questions here. Well, I love this topic,

obviously. Melatonin, you've brought that up a couple times as something that our body releases as a way to let us know it's time to sleep. Of course, we can take melatonin. What do you recommend there? So I actually take melatonin regularly and I recommend people try it in the book because I can't find a downside. I looked at all the safety studies and different dosages. There's a major issue around dosing of melatonin because people are taking way more than they need. But even in children, older adults, the studies show that supplementing sleep with melatonin, it doesn't. It doesn't. doesn't seem to hurt. And our rates of melatonin decrease as we get older. So if sleep onset is a problem or sleep maintenance, maintaining your sleep is a problem, giving melatonin a try, I would say start

at one milligram, do it for a couple weeks. And because it's not a sleeping pill. It's not something that is like an ambient that you put in your system and just stay in bed or your all sorts of crazy stuff is going to happen, right? It's just a gentle kind of push of your circadian rhythm. to a more sleepish state. Also thinking about melatonin in terms of as the sun sets, that decrease in blue light is the signal to start releasing melatonin. So melatonin actually gets released quite early before your bedtime. So taking it, say, two hours or one hour before bed is what I would recommend because it's not something that you want to take when you're already in bed, then that release is going to take a while to turn on, right? You want to as much as possible mimic

the natural times in which melatonin would be released. Another thing you've mentioned is breathing through your nose all night long, and I read that and I was thinking, well, how can I control that? So one of my favorite books recently is Breath by James Nestor. That guy really mined some powerful information there showing that we've become a society of mouth breathers. And it's changed our anatomy, it's changed our physiology, and it's changed our disease risk. And so I really took it to heart, understanding that there's a natural system that is the nose. And it gives you filtered, moist, slow breaths. That is the natural way to synchronize your breathing and, and you're

and your heart rate so that your ability to get as much out of your inhale is that it's most efficient if you're breathing through your nose. I've started breathing through my nose for everything I do and including having my kids breathe through their nose. Hiking, running, it's really hard to learn to breathe through your nose for everything, but you become a more efficient athlete. You become a more efficient breather because it takes a lot less energy and mouth breathing is very shallow so you don't get enough oxygen. And it's too quick. You know, this is all talking about how to breathe through your nose during the day and really make that intentional, but there's a really important aspect of nose breathing for sleep because the mouth breathing,

you have all sorts of sleep apnea that occurs through mouth breathing and you get very sore throat, dry throat through mouth breathing, and you can have more collapse in the airways through mouth breathing. So training yourself to really engage in nose breathing either by, I haven't actually advanced to this level yet, but either by just making sure that you're always sleeping in a position that accentuates nose breathing over mouth breathing. I think lying on your back is a very hard way to nose breathe because your mouth just naturally relaxes and opens. So sleeping on your side is preferable to kind of inducing nose breathing. But also, you can just take a little piece of tape. And it's just, it's not going to seal your mouth shut, but it's going to be just a gentle reminder

throughout the night to keep your mouth shut. And if you feel like your mouth breathing, you'll know it, right? Because it'll sort of be pushing the tape and maybe even let go of the tape and that might wake you up or something. But that is one of the things that he recommends. Also getting the sleep apnea treated. There's many ways in which sleep apnea is causing a lot of mouth breathing. So highly recommend nose breathing. This has been a great conversation. Is there anything I should have asked but didn't? I mean, I can tell you so many more things. There's the idea. idea of resonance. But I also really like to talk about this is that we talk about individual rhythms of our sleep system or our exercise system. Each metabolic system has its own rhythm. But there's this idea in physics, which is that if you have these two rhythms that have their upstates and downstays synchronized, that they become more powerful. They resonate. And I think that's a key way of thinking about these rhythms of your own body, that when you set up.

up these rhythms to actually become in sync with each other, both systems resonate. When you're eating within your daytime circadian upstate, you get way more out of your nutrition, and then your downstate is much more powerful in terms of giving yourself a break and replenishing. When you exercise in the morning during the upstate of the day, your downstate from the exercise corresponds with the downstate of sleep, allow for that restore response to be even more powerful. Once you start to get into the idea of thinking yourself as a rhythmic animal, that you can start to really get sophisticated and start aligning your daytime, nighttime processes

to get the most out of yourself and your day. And you can learn more about how to do that in your book. Speaking of which, can you just plug everything you've got or that you feel like plugging? Yes. My website is Sarah, S-A-M-E-D-N-I-C-K. All my talks are there and different types of podcasts, but there you can read about my book, The Power of the Downstate. And you can see my other book, Take a Nap, Change Your Life, which is all about how naps can be used as not just restorative system, but also to make you smarter and happier and all sorts of stuff. And I'm on Twitter, Sarah underscore Mednick.

You're a star. Thank you so much for doing this. Really appreciate it. Thank you so much. It was such a pleasure talking to you. Thanks again to Dr. Sarah Mednick. Don't forget, it's Sleep Week. Over on the 10% app, we've got a bunch of new sleep meditations we've just dropped. It's really great stuff. Sleep is so important and meditation is so helpful. Also, just to say there's a free 14-day trial if you want to try before you by,

you can join the party at Dan Harris.com. Finally, thank you to everybody who works so hard to make this show. Our producers are Tara Anderson and Eleanor Vassili, Our recording and engineering is handled by the great folks over at Pod People. Lauren Smith is our managing producer. Marissa Schneiderman is our senior producer. DJ Kashmir is our executive producer. And Nick Thorburn of the band Islands wrote our theme.