Joining me on the show this week is Dr. Greg Potter, Co-Founder and Chief Science Officer of Resilient Nutrition, a nutrition and supplement company that uses nutrition to help people be more resilient. Since he did his PhD on sleep, circadian rhythms, nutrition, and metabolism, Greg spends much of his time helping individuals sleep, eat, feel, and perform better. Highlights of Greg’s career include coaching a sprinter to four gold medals at the European Championships; having his research featured in dozens of international news outlets, including the BBC, Reuters, and The Washington Post; working with the US Naval Special Warfare Command; helping to prepare two men to break the Atlantic rowing World Record; and being the sleep expert in a Channel 4 documentary on sleep and weight loss.
We dive into the episode discussing why sleep matters, particularly when it comes to your everyday housekeeping and brain functions and understanding how to navigate within both. Dr. Greg Potter unpacks the importance of sleep and its effect on athletic performance including its connection to injury risk factors, motor skill learning, immune function, testosterone levels, and recovery. When thinking about sleep health, you should always consider the amount of sleep, the quality of sleep, the time you sleep, and the regularity of sleep to find a good sleep rhythm that works for you.
Listen in as we share a list of action steps to balance sleep in a healthy way: setting an alarm clock for yourself as a reminder to go to bed to increase sleep regularity, having time to unwind before going to bed (e.g., reducing your exposure to light, taking a hot shower one hour before bed, and listening to music), keeping your room cool and dark, going to bed only when you feel tired, and finding a relaxation strategy to practice. With sleep probably being the most powerful performance cocktail around and has the ability to drastically improve your performance faster than any other intervention, we should all be prioritizing and understanding the why behind it.
What you’ll learn in this episode:
- [07:08] Why sleep matters
- [11:11] Aspects of sleep relevant to evolution
- [13:51] Understanding sleep maintenance
- [15:25] Sleep and its effect on athletic performance
- [25:34] Sleep and the 90% rule
- [27:59] The importance of sleep regularity
- [28:53] Action steps to regulate sleep
- [34:29] Relaxation strategies to consider
- [39:49] Caffeine intake recommendations
- [41:18] Alcohol intake and its effect on sleep
- [45:30] How much sleep you should be getting
- [51:45] Tools to track sleep quality
James Cerbie: Hey there team, what is going on? Welcome back to Rebel Performance Radio. On the show today, I have Dr. Greg Potter on board to discuss all things sleep, because sleep is one of those things that we all know we should be doing; we should be prioritizing it. But very few people actually understand what’s going on underneath the hood. Why? Why do you need to be prioritizing sleep? We dive in and unpack things like sleep and brain function, sleep and motor learning, sleep and recovery, sleep and immune function, sleep and tendon health, sleep in your athletic performance.
And then on the back end we jump in and talk about what are the action steps, what are the things you need to be doing so that you can better prioritize sleep and be getting better sleep. Because if you’re going to be putting in the effort in the gym to get stronger, put on muscle, become more powerful, build your conditioning and endurance, whatever it is, you’re going to be putting in all that effort in the gym, but you’re not going to prioritize your sleep, then what’s the point?
Right. Making these changes, getting these adaptations we’re changing and chasing are already a lot of hard work. And sleep is such a powerful performance cocktail like we’re going to talk about on the show today. And it’s funny because I think if I talked about all the things sleep does for you, but instead pitch it to you as, hey, here’s this really easy supplement. This is what it’s going to do for your performance, your health, your longevity.
Everybody would jump on this supplement. So, it’s the easiest, lowest hanging fruit. It’s the number one thing that you can do right off the bat to drastically see changes in and improve both your performance, your mental clarity, your mental sharpness, your happiness, all that jazz. So, really excited that Dr. Greg Potter came on board to unpack all this for us. There are so many good, actionable takeaways here.
We actually took the entire episode and got you a really nice, cleanly made transcript that you can go and download. I personally like having these things, so I can read through them and highlight the things that I like. So, the link to the transcript that you can download will be in the show notes. Otherwise, let’s jump into the episode today with Dr. Greg Potter.
There we go off and running with the one and only Greg Potter. Greg, thank you so much for taking sometime today from across the pond, from overseas to sit down and just chat a little bit.
Greg Potter: Pleasure to be here, James.
James Cerbie: Let’s do this. I’m sure you’re tired of doing this. You’ve got to do it all the time. But the elevator pitch, right. People are listening to this. They’re going to be like, who is this guy? Can we give him the quick rundown on who you are and what you do? And then just so people listening; we’re going to be diving in, talking about sleep today. I’ll leave that as the little nugget. But I’ll turn it over to you.
An Introduction to Greg Potter and Resilient Nutrition
Greg Potter: I’m very interested in how to help people feel and perform better. And initially, I was more interested in performance and sports performance, in particular. I did an undergrad and a master’s in exercise science focusing on exercise physiology at Loughborough University, did a lot of coaching while I was there, personal training, but primarily with strength and power athletes and between those degrees, also worked at the rugby union in the sports science and sports medicine department. But over time, I increasingly recognize the importance of sleep and biological rhythms to how we feel and function. I also did a PhD that focused on the intersection between sleep, biological rhythms and metabolic health.
And since then, I’ve been involved in various different projects, all centered on that theme. And nowadays, I am the Co-Founder and Chief Science Officer at Resilient Nutrition at resilientnutrition.com, which is a UK based nutrition startup that makes U.S. products. And unfortunately, they’re not available on your side of the pond just yet. But that’s how I spend most of my time nowadays. I still do some work as a consultant, helping groups and individuals.
James Cerbie: Beautiful. I love it. And apologies; the introduction should have been Dr. Greg Potter. You very much deserved that in that front end.
Greg Potter: Not a real doctor.
James Cerbie: I have some people over here where I was in grad school at. So, they’re the PhDs and they’re like, we’re the real doctors. We had it first and then these other people came along and the whole M.D. thing; they hijacked our doctor thing. And then now they call themselves doctors and blah, blah, blah. But yeah, I would love to jump right in today, start diving into this this whole sleep topic, which is huge.
It’s big. We’re obviously still learning a lot day by day, week by week, year by year, unpacking why sleep actually matters. It’s that thing that pretty much everyone knows they should be doing; it should be a priority. I should be doing it more probably. I think very few people understand 1. What are some of the whys behind why do I need to sleep? What’s actually going on physiologically underneath the hood that makes this so important?
And then towards the back end of the episode, we can dive in with some actual action steps to go and make sure that we’re getting better sleep because for our population, people that are right, we’re training. We’re getting to the gym; we’re getting after it. Performance is a huge priority for our people. If you’re not appropriately prioritizing and hitting that sleep lever, you’re just going to be leaving so much on the table.
And I’ll preface this with when people always ask me about sleep, I like going with if we just want to look at this from a very rudimentary standpoint, just purely evolutionary. If sleep wasn’t one hundred percent essential for some reason, it would have dropped off over the course of thousands of years of evolution, because if a small band of humans could have figured out how to operate without sleep, they would have an enormous evolutionary advantage.
So, the fact that it stuck around for as long as it has means that there is something incredibly important going on there. And so maybe we’ll start here, our ten-thousand-foot view of the forest. What’s that ten-thousand-foot view of why sleep matters? And then we can zoom in on some specific examples that I know that you’ve got as well.
Diving into Why Sleep Matters
Greg Potter: Sounds good. This is a question the scientists have wrestled with for some time, and while there’s no consensus as to what the right answer is, I think most people would agree on a few fundamental processes that sleep is integral to. So first, one way of thinking about this is in terms of housekeeping functions. Sleep is involved in all sorts of housekeeping processes and different bodily tissues. Take the brain, for example. In 2013, though, some preclinical research showing that during the deep stage of sleep in particular, spaces in the brain’s lymphatic system, which is a bit like the brain’s immune system opened up during this deep stage of sleep.
And at this time, cerebrospinal fluid washes metabolic debris that’s accumulated during wakefulness out of those spaces, removing the garbage, if you like. And a couple of years ago, some work was done showing that the same thing happens in humans. And it seems to be that electrical activity in the brain results in changes in blood flow, and it’s those changes in blood flow that result in changes in movement of that cerebrospinal fluid through those spaces. If you think about different bodily tissue, then we know that sleep is very important to other aspects of immune function, too.
And perhaps the most pertinent example of this right now is that if you restrict people sleep or deprive them of sleep around the time of vaccination, then that immune responses to that vaccination appear to be substantially diminished, at least for most of the vaccinations that are studied today. So if you look at some of these antibody titers weeks or even months after vaccination, if they’ve been deprived or restricted of sleep, then they’ll have a low antibody titers. If you look at different bodily tissues, such as the musculoskeletal system, we know during a deep stage of sleep, our bodies produce most of that growth hormone over the 24-hour cycle, and that growth hormone is very important to remodeling connective tissue.
A lot of people once thought the physiological amounts of growth hormone are important for muscle protein balance and growth hormone administered exultantly doesn’t seem to lead to a substantial increase in muscle mass, but certainly is important if you want strong tendons, ligaments and so on. So, there are those housekeeping functions. But I think a really important role of sleep is brain function and in particular our ability to better understand the world and how to navigate within it. And one model that I particularly like was put forward by Robert Stickgold and one of his colleagues, Anthony Zadra, which they call network exploration to understand possibilities, and I won’t go into all details of this model, but the idea is that during sleep, there are certain stage of sleep in which we consolidate memories.
Aspects of Sleep Relevant to Evolution
Then there are other stages of sleep, some particular rapid eye movement, which is the stage of sleep in which we have our longest and most vivid dreams that are important to taking existing memories and then creating weak associations between those memories and other previous experiences. So, during this stage of sleep in which we try and model the world around us in a safe environment so that during wakefulness we have a better chance of surviving and ultimately passing on our genes. And then there are also some other aspects of sleep that are probably relevant to evolution, so one is energy conservation. A lot of people used to focus on this during sleep; metabolic rate is on average lower than it is during wakefulness.
Core body temperature is lower, and that period of adaptive inactivity presumably serves some evolutionary functions. But like you said, of course, you can’t procreate while you’re asleep, so if we were always inactive, then we probably wouldn’t have fared so well. And there are some people that have speculated that sleep might be the default state for organisms. And I’m not sure what I make of that, to be honest. And then there are various other processes, too.
But a simple way to think about all of this is the sleep helps prepare our bodies for subsequent wakefulness. And when we deprive ourselves of sleep, all sorts of things go wrong.
James Cerbie: Yes, without question. So, a couple of really cool examples going on there because if we think about the example of what’s going on in the lymphatic system and the brain, the ability of when you’re in deep sleep, to actually clear out, let’s just call it, “the garbage” that accumulated throughout the day. An easy kind of segway tie into that analogy is similar to what our people could probably tap into a little bit easier, which is, what’s going on when you train?
So, I know that when we train, like if I was just doing a knee extension, for example, it’s not going to be a perfect one to one correlation. Right. But you have to be able to clear out the metabolic byproducts that are being created when you exercise or else, you’re going to start running into all sorts of problems. We get massive pH changes, protein function is going to go down, etc. So, we have these things are happening very acutely at the muscle.
And that’s why our capacity to deliver fresh blood flow, new oxygen, to take away the things that are actually accumulating so we can change potentially what’s going on, figuring out what’s getting fed back to the brain. Right. So, if we think about that happening at the local muscle level, the brain is is a tissue that’s going to need to have some type of mechanism in place to deal with similar byproducts and things that accumulate over the day from just using that tissue.
Right. And so, I think a potentially interesting question here, and I’m not sure because I’m not very well read in the sleep literature at all. But why is it that when we’re waking, when we’re awake, we can’t get that same type of clearance and maintenance that we get then when we go to sleep?
Why We Don’t Get the Same Maintenance Awake as We Do Asleep
Greg Potter: It’s a good question. I think part of it probably has to do with energy conservation; if your body tries to do everything all at once, all the time. Then, that would be enormously, energetically costly, and that probably underlies part of the reason why biological rhythms evolved. We live in a cyclic environment. There are roughly twenty-four-hour change, the light, dark cycle temperature, food availability and so on. And to thrive in those changing environments, our bodies evolved these biological rhythms that temporarily compartmentalize these distinct processes, so we don’t end up spending too much energy.
We have that period of adaptive inactivity in which we can make sense of the world. And ultimately that seems to be a more successful strategy than other ones that have been explored, at least for most organisms. And if you look across different organisms, then it seems that all mammals studied, they probably sleep. It doesn’t necessarily seem that every organism sleep; there are possibly some rare exceptions. So, African bullfrog might be one of them, for instance. Certainly, the fact that sleep is independently evolved in so many different types of organisms suggests that it has some of those core functions that are needed for survival.
But one thing that might be helpful, James, is to just to lay out why sleep is important to athletic performance.
Why Sleep is Important to Athletic Performance
James Cerbie: Yeah, I think that would be beautiful.
Greg Potter: There are a few different ways of thinking about this. One is in terms of your ability to adapt to training and to train effectively from day to day. And there have been multiple prospective studies showing that people who get less sleep are more likely to go on to injure themselves in days to come and of the different injury risk factors that have been identified in those studies, sleep is among the strongest.
And if you’re injured, then you’re not going to be able to train hard enough to get the adaptations you’re looking for. So that would be one of them. Another is that sleep is probably very important to motor skill learning too, and early experiments done by Jouvet showed that rapid eye movement sleep might be particularly important. So, during the stage of sleep in which you should be dreaming, part of the brain or as much as 30 percent more metabolically active than they are doing today, but many of our muscles and our skeletal muscles in particular are paralyzed, and that creates a safe space in which to try new motor programs.
And it’s possible to disrupt the central nervous system in such a way that that inhibition of those muscles no longer takes place, and you’ll see animals acting out their dreams and various motor skills and trying to pick up during previous waking hours. So that might well be necessary to motor skills. But we also
know that some of the non-REM stage of sleep and particular deep sleep might be important to procedural memories, too. And there are different types of memories as declarative memory.
So, memory facts, for instance, procedural memories and memories, how to do things or how to ride a bike, for example. So, it’s probably important for motor skill learning in terms of training. Obviously, things like your immune function are very important. And if you get sufficient high-quality sleep, which is well timed and regular from day to day, then your immune system will simply function better. So, you’re less likely to skip workouts because you have an infection.
Then there are those bodily processes that take place during sleep that are important adaptations to train. I mentioned growth hormone; if you look at the circadian rhythm of testosterone synthesis, then it’s at its highest in the late sleep period. And if you restrict people sleep, then while the dates aren’t entirely clear, they generally show you the people who get less sleep experience reductions in testosterone levels subsequently. And that’s certainly true of older men. It’s probably true of younger men, to a slightly lesser extent.
Obviously, testosterone is important to various restorative processes, in particular to muscle protein balance. Then, there are the acute effects on performance. So, in the case of endurance training, I’m guessing that would be of less interest to many of your listeners. Then, it’s clear that if you deprive somebody of sleep, they’re raising a perceived exertion during subsequent submaximal, maximal endurance task will be higher at a given work rate, than if they had sufficient sleep the night before. It also seems that there are times exhaustion which isn’t so ecologically valid; it’s not so relevant to many sports, but it is still an interesting parameter to look at in this context might be impaired by sleep loss.
And intermittent sprint performance might be worth something about some of the biological basis underlying this, I think much of the reason for these changes. Probably is due to brain function, but there might also be changes in things like muscle supply chain stores and so on that could contribute too. With respect to resistance training, there was a systematic review published not long ago showing that if you look across different studies than multiple nights of insufficient sleep, might well reduce performance in multi joint resistance training, in particular multi joint modern repetition trainings.
The Effects of Sleep Extension on Sports Training
I think of doing something like a bench press for 8 to 10 reps. Your performance during that type of work, which comprises the bulk of those people training is likely to be impaired. And then there haven’t been many studies, to my knowledge, looking at adaptations to training when people either have enough sleep or don’t have enough sleep. But when you put all of that together, I have to think that somebody who doesn’t get enough sleep isn’t going to respond so well with training, and there have a couple of interesting studies that have looked at the effects of sleep extension on sports performance.
So, of all the different sleep enhancing interventions that have been studied, naps, sleep hygiene, education and so on, sleep extension seems to be the most performance enhancing to mention a couple of these, there’s a highly discussed study in 2011, I believe, looking at the Stanford University men’s varsity basketball team, and they went through about six weeks of sleep extension, which they tried to get as much time in bed per night as possible, aiming for 10 hours in bed during that period.
And they had dramatic improvements in everything from their speed and multidirectional sprint, to their free throw and three-point field goal percentages. And they also simply felt better. And subsequent studies have also looked at the effects of sleep extension on things like serving accuracy, showing improvements on time trial performance in triathletes, again showing improvements. So, hopefully some of that will make people realize that sleep might be quite important if they value their gains.
James Cerbie: And the way that I think about it and hearing you describe it is, sleep is this incredibly powerful, integrated cocktail, almost. When you’re getting good sleep, you’re getting this physiological cocktail that is stacking the deck in your favor, so that you can have better motor learning and skill acquisition. You can have better immune function, you can recover and adapt to training better, etc. If that cocktail of that environment isn’t there because we pull sleep away, it’s already hard, you’re just making it harder on yourself.
Right. And I think one of the things that’s funny to think about is, if you were to walk up to somebody and say, hey, I have this supplement, this new supplement, it’s awesome. Here are all the things it’s going to do for you. 99 percent of people would be like, oh, yeah, hook me up. This sounds awesome. Right. Then the minute like, oh yeah, that supplement is just sleep. People are like, oh, that’s boring.
I don’t want to do this. But at the end of the day, you’re so worried about supplements and this and that, or the other and it’s the lowest hanging fruit. The one thing staring you in the face that can probably give you the biggest ROI bang for your buck. It’s just getting better with your sleep. Across the board, it’s going to help, like you said, and one of the things we talk with our people a lot about in training, it’s not about any one day I’m not going to get better in one day.
You can get worse in one day because you can get injured. Right. But just one day of training, one day of lifting is not going to do anything in terms of making you better. It’s not going to create significant physiological change. We make adaptation improvement and change over time. It’s about stacking together as many good days as we can. It’s about having one good week, which is one good month, which is three good months. And now we’re seeing huge changes.
Right. But where people get themselves into trouble, it’s like, oh, three to four good days. And then I got to fall off and then I got three to four good days and then I fall off. You’re never going to get anywhere. Those are the people who are like, well, I’m just stuck in the mud. Right. And they’re always wondering, well, what should I be doing? And that’s one of the reasons I wanted to have this conversation, is because sleep is so big; it’s so important.
Like you just said, everything that you mentioned, it’s the cocktail. There’s no reason for you to not prioritize this. It’s like drinking a super cocktail every day for your performance, essentially. And it’s one of those things that everyone knows they need to be doing, but just aren’t prioritizing. And so, maybe this will be a good opportunity to transition slightly. And we can start talking about action steps, things that people can be putting in place in their lives to better prioritize sleep to make this happen.
Because I know there are plenty of people out there who are probably pounding like a 16 ounce black coffee at three o’clock in the afternoon. And they’re like, yeah, you know, I just don’t sleep that well. I can speak for myself. Right. I’ve always loved sleeping, but it just continues to become more of a priority for me because everything in my life gets better when my sleep is good. Everything. I’m more creative, I’m more thoughtful, I’m more productive, my training is better, I adapt faster, I recover better, I’m happier. I guard my sleep window really tightly.
I don’t go out much. If I do, we’re home by eight thirty, nine o’clock because I want to be in bed. So maybe let’s approach here and think about a list of action steps for people here that they could walk away with and start implementing in their lives to get better sleep. Maybe we can chunk these just one by one and see what we can come up with.
Greg Potter: Perfect. One thing I want to make clear is that the occasional night of poor sleep isn’t something that you should be concerned about. You should strive for regularity. But if you want to go out with your friends from time to time, and that makes you anxious because you’re concerned about the negative effects on sleep, don’t worry about it. Enjoy yourself and everything will be OK.
Sleep and the 90% Rule
James Cerbie: Yes. Thank you for that. I will just piggyback on that super quick because I do see this also sometimes. 90 percent rule, right? A similar thing in the nutrition realm. If you’re good 90 percent of the time and then go have fun and give yourself some leeway to play. But you don’t adopt this fragility mindset because I do see this, too. And this is the opposite of the spectrum, that’s not good. Where someone’s like, I didn’t get my eight and a half, nine hours of perfect sleep.
I’m just ruined today. There’s no chance I can function as a human. It’s like, OK, well, that’s also not true. Right. So, let’s make sure we stay somewhere in the realm, live in the middle. I like the bell curve. Stay more in the middle of the bell curve here.
Greg Potter: So, one thing to add to that is that if you do generally sleep well, then you better buffer yourself against the negative consequences of occasional poor sleep.
Factors That Go into Sleep Health
Now, with that said, when we think about sleep health, there are few things to consider. There’s how much sleep you’re getting. There is the quality of your sleep. And there are different dimensions within that. One is how long it takes you to fall asleep. What is your sleep efficiency? So, the proportion of time you’re in bed, you’re actually asleep. You can also look at some finer grained details, such as the patterns of electrical activity in your brain, how you breathe during sleep and so on.
But let’s put sleep quality into one category and just bear in mind that it has both those objective metrics, but also your simple, subjective perception of how well you feel when you sleep. That’s the timing of sleep. Anybody who works shifts will know that if you try and sleep at a suboptimal time, you’re probably going to sleep very well off, very long on average, shift work and sleep about an hour less than the non-working counterparts. And then there is the regularity of sleep.
And the reason I mention all of these different dimensions is that they all independently predict various chronic health conditions such as coronary heart disease. Now, with that said, based on that, how would we like sleep to be in a perfect world? You would wake up in the morning feeling like you had high quality sleep at roughly the same time each day. You’d have good, safe daytime function. Your memory would work effectively, your athletic performance would be high and so on.
The Importance of Sleep Regularity
You’d feel drowsy roughly the same time each evening. You’d then fall asleep quickly and get sufficient sleep, and that person would repeat itself day on day. And that brings up one key point, which is the importance of regularity. So from day to day, you would ideally have quite similar bedtimes. With that said, you should only ever go to bed when you’re actually sleepy just because you’ve designated 10:30 pm is your target bedtime. If you’re not sleepy at 10:30 pm, you should not go to bed and then lie in bed awake because that will actually negatively affect your subsequent sleep.
If you’re struggle with regularity, then you could set an alarm clock about an hour before you plan to go to bed to remind yourself that that is your target bedtime. There are also instances in which I think waking to the alarm makes sense, the most common of which is insomnia. But I won’t go into details about that. But regularity is key. Having time to unwind in anticipation of going to bed each night is really important.
Action Steps to Take to Regulate Sleep
And there are lots of different things that you could do at this time, but some cool ones would be beginning maybe 90 minutes or so before your planned bedtime, it makes sense to systematically reduce your exposure to light and in particular to light, that contains lots of short wavelength light, which would appear to us as blue or green, but full spectrum, white light also has a lot of lights in it. So simply, if you turn some lights off in your home or if you dim the lights, if you have dimmers, then that’s a useful strategy.
And if you’re going to keep some lights on, then the best lights to keep on are probably lamps, because perhaps unsurprisingly, in the context of evolution, it’s overhead light that may strongly affect our bodies’ clocks. And if you expose yourself to lots of light at this time, then you’re going to shift your clock later; shift when you feel sleepy later. And lights also have some independent lasting effect. So you find it harder to nod off when you do go to bed.
Now, in terms of other things you can do at this period, one really helpful strategy is having a hot shower, hot bath. Something like a 10-minute shower at about 40 degrees Celsius, that isn’t Fahrenheit, James, I’m sorry.
About one hour before your planned bedtime will raise the temperature of your skin by a couple of degrees Celsius. And the reason that’s a good thing is that when you then get out of the shower, you’ll actually lose heat from your core faster than you otherwise would. And a drop in brain temperature specifically by one degree or so around the time you go to bed. Help speed entry into sleep. So, when people have a hot shower, hot bath at that time, they tend to fall asleep faster.
And the quality of that subsequent sleep tends to improve as well. Other activities that are ideal at this time include things such as reading a book and listening to relaxing music. And obviously what’s relaxing to you might be quite different from your spouse. So, there might be a happy middle ground, but it’s very clear that simply listening to music can be really helpful for people who are struggling with sleep, such as individuals who have insomnia.
And then in terms of the sleep environment itself, you want your bedroom to be cool, dark and comfortable. The ideal air temperature, if you have air conditioning, is probably around 19 degrees Celsius for most people, although it’s personal variability and thermal preferences. And in terms of the lights in your bedroom, you should try and remove any non-essential lights emitting devices. Perhaps the most relevant of these right now is phones. If you look at what’s happened during the Covid-19 pandemic, many of us are spending more time in front of screens than we used to.
And it’s clear that that can negatively affect sleep, which probably happens through several mechanisms. One of these is the light exposure from the devices, which, to be honest, probably isn’t that substantial in terms of its effects on sleep if you’re spending enough time outdoors during the day. Another is the content of the media you’re consuming. If you do scrolling, then you might find that quite arousing in the wrong way and that might negatively affect your sleep. And then another is probably your loss of sense of time passing.
And anybody who has Netflix, they will be intimately familiar with this phenomenon
James Cerbie: That auto play bar goes so fast.
Greg Potter: So, turning off your phone about half an hour before bed and keeping it out of your bedroom and then only turning on when you’re up the next day is a really good place to start. And there’s been work looking at young adults recently showing that when they do this, they fall asleep faster; their sleep efficiency is higher. They get more time to sleep. And as a result of the change in their sleep the next day, their working memory improves. So, you will improve some aspects of your performance in the days to come if you follow that simple tip, if that’s something you currently struggle with.
And then there are probably a few different things people should consider. I mentioned earlier that you should only go to bed if you actually feel sleepy. Related to this, if you’re lying in bed at the start of the night, or if you wake up during the night and you haven’t fallen asleep within 20 minutes or so, you should get out of bed, go to a different room, do something relaxing, dim the lighting, and then only go to bed when you actually feel sleepy.
This is most relevant to people who have insomnia. The reason is that a lot of these people will forever try and catch up on their sleep or spend more time in bed during the day. They’ll try and nap during the day and then at night they’ll lie in bed awake. And the problem is that because our brains are so good at creating associations between things, they learn to associate their beds with somewhere that they’re awake, and they need to recondition their brains to associate that beds with somewhere they sleep.
Relaxation Strategies to Consider When Falling Asleep
And that’s how they do that. The other aspect to this is saving the bed for sex and sleep only. And then there are some simple relaxation exercises that people can do if they’re struggling to fall asleep, and it’s probably worth playing around with some different ones. Because while some are better on paper than others going by the research done so far, there are quite big differences between people in terms of how they respond. One of these is progressive muscle relaxation, which is helpful for some athletes struggling with bodily discomfort.
And this entails sequentially scanning through the body, contracting certain muscles, holding the contractions for six seconds or so and then relaxing. And as you relax, you exhale. So, you might begin with the muscles of the feet. So, you clench your toes to start, and then work your way upwards through your body. So, you move from your feet to your calves to your thighs and so on until you’re up at your face. And a lot of people find that if they do that for a short period, they’ll soon nod off. Another strategy that can be helpful is counterintuitive to most of us.
It’s called paradoxical intention. And the idea is that what you resist persists. So, if you’re lying in bed and you’re telling yourself to sleep, then you’re probably going to stay awake. If, however, you’re lying in bed and it’s a dark room, the sleeping environment is a good one, the better strategy is to gently hold your eyes open. And then as time passes, congratulate yourself for staying awake but relaxed. And if you do that, you’ll probably fall asleep quite quickly.
I know that you’ve had some podcasts, some breathing previously, James, and or at least it’s come up in previous podcasts, and simple breathing exercises can be helpful, unsurprisingly, because of their effects on the parasympathetic branch of the autonomic nervous system in particular. And while the optimal parameters probably vary by person, simply breathing slowly and deeply through the abdomen and through the nose, promotes relaxation and will help a lot of people fall asleep faster. And if you wake up during the night and you feel quite worked up for whatever reason, that strategy can be handy as well.
And then finally, I’ll just mention the things that you do during the daytime will also strongly affect your sleep. One of these is physical activity, and I suspect that most people listening to this are doing enough activity as it is, and probably more relevant that when people enter overreaching or even overtraining, sleep tends to suffer. And some people have actually looked that poor sleep as a potential biomarker, if you like, of overtraining. So, getting enough physical activity is definitely a good thing for sleep, because energy expenditure in particular seems to be important to promoting sleep, but doing too much can be stressful.
And if you do too much, then both the quality and quantity of your sleep can suffer. And then obviously there is the timing of your activity. So, while the data on this aren’t entirely clear, and that was a meta-analysis published not long ago showing that exercise might not strongly affect sleep, I think in the real world it probably does, especially for somebody who is hard charging. If you think about working out, a lot of people go to the gym, they’ll be listening to loud music, they’ll be under bright lights and they’ll be lifting heavy weights for high volumes.
In a research setting, somebody might be doing moderate exercise on a treadmill in a relatively dimly lit room for half an hour. Yeah, those are quite different stimuli in terms of their potential effects on sleep. So, for that reason, if you’re doing any type of high intensity exercise, then I typically recommend that the exercise should finish at least four hours before sleep, if possible. And if it’s not possible, then I think the relative importance of some of these strategies I mentioned probably increases, if anything.
And then finally, obviously, there are the different things that you ingest, and certain medications will strongly affect sleep. And there’s a huge gamut of these. But the most relevant pharmaceuticals to sleep for most people are, unsurprisingly, nicotine, caffeine and alcohol. Nicotine affects sleep and some quite complex ways, depending on things such as whether somebody is a regular user and habituates nicotine or not. But obviously trying to limit smoking and nicotine consumption over time is a good goal for various reasons.
Caffeine Intake Recommendations
In respect to caffeine, people respond very differently to it. And while on average the half-life of caffeine, so the time that it takes for the maximum concentration of caffeine in your blood to come down by 50 percent is about five and a half, six hours for most people. If you take somebody who has some sort of liver disorder. It might take more than 24 hours for that number to come down by 50 percent. So, you have to bear in mind your own individual response to caffeine. With that said, I think for most people, beginning by stopping consuming any caffeine containing items, at least eight hours for bed each day is reasonable and doable.
The higher the dose of caffeine you consume, the idea that you should finish. And with respect to athletic performance, I think there are rare circumstances, for example, ultra-endurance activities, where you might go above this number. But if you are strength athlete, then I can’t think of any circumstance in which it makes sense to consume more than six milligrams of caffeine per kilogram of body weight per day. And for most people, three milligrams per kilogram of body weight per day is probably a better goal on a regular basis.
There’s a website, caffeineinformer.com, you can go to to find out more information about the caffeine contents of commonly consumed items. I actually just wrote a blog about caffeine at resilientnutrition.com. I think the title was, “In Defense of Caffeine,” just because I hear a lot of sleep researcher types and also nutrition companies nowadays eschewing caffeine, saying it’s evil, it will destroy your sleep. And the reality is that if you’re somebody who sleeps quite well, you’re a habitual caffeine consumer and you feel like you’re not that sensitive to caffeine, it most likely has a negligible effect on your sleep provided you don’t consume too much too late in the day.
Alcohol Intake and Its Effect on Sleep
And then finally, with regards to alcohol intake. If people consume booze late in the day, then they will fall asleep faster on average and they’ll spend the greatest portion of the early sleep period in the deep stage of sleep, which to some people sounds attractive. But the problem is that alcohol will subsequently disrupt sleep in a few different ways. So, one of these is just the alcohol is a diuretic, and if you consume it, then you’re more likely to wake up needing to pee, and that will fragment your sleep.
Another is that it’s a muscle relaxant. And I suspect a lot of people listening to this are quite big individuals. And the girth of the neck strongly influences your risk of experiencing obstructive sleep apnea, and I suspect a lot of people listening to this are also male. Being male, unfortunately, poses a high risk of sleep apnea than being female. So, if you experience intermittent collapse of the upper airway during sleep, for example, your partner has noticed that you occasionally stop breathing during sleep, then you should probably minimize your alcohol intake because it’s likely to exacerbate that collapse of the airway.
Likewise, if you’re a snorer, then alcohol will tend to make that worse too. Snoring is not benign, even though a lot of people think that it is. It’s worth seeking some additional guidance on it. That’s the case. Those were a lot of tips. I’ll just mention a couple more things. One is that if you feel that you sleep very poorly, you should seek additional help. And that might entail going to a medical doctor, but there are lots of resources out there that are great first ports of call people, one of which is the AASM website, the American Academy of Sleep Medicine website.
And then if you’re struggling with insomnia. The front-line therapy for insomnia is typically cognitive behavioral therapy for insomnia, which is a combination of different psychological and behavioral interventions designed to address maladaptive thoughts and actions that he might have developed over time as your sleep is deteriorated. So, with that in mind, there are various online CBT programs, some of which are free that you might want to check out in the UK, for example, this one called Sleepout, which I really like.
I don’t know if it’s available for free in the US, but I think it probably is available. And then I also just mentioned sleep apnea because it’s probably the second most common sleep disorder after insomnia. And it is a big problem. Not only does it make people feel very sleepy during the day and therefore increased risk of things like traffic accidents, it also strongly, negatively affects metabolic health in various ways. So, if your partner has witnessed you stop breathing during the night and you think that there’s a chance you might have sleep apnea, check out, stopbang.ca, and you’ll find a free questionnaire that you can answer to estimate the likelihood that you have it,
And then if your score isn’t as good as you would like it to be on that questionnaire, you could seek additional help. So sorry, James. That was quite a lot.
James Cerbie: No, perfect. Yeah, no, it’s beautiful. We could talk about sleep for so long. So, a couple of things here. One, I know that there will be people listening to this. And the question in their mind, I think can be floating around is, “How much time should I be sleeping?” And there’s going to be a range and it’s going to depend on you, because I know that there can be some people who do fine with a little bit less sleep.
Some people are going to need a little bit more sleep. But is that recommendation of, let’s shoot for ballpark 8 hours a night? Is that still a pretty spot on recommendation for people? Maybe we bump an hour up, if we can, to 9.
How Much Sleep You Should Be Getting
Greg Potter: Every once in a while, a bunch of sleep scientists get together to come up with consensus statements about things such as how much sleep people need, and the National Sleep Foundation consensus guidelines are recommending seven to nine hours of sleep per night for 18-64 year old adults. For adults that are 65 or older, that number is seven to eight hours per night. But with that said, those are averages and there’s quite a large variation between people and how much sleep they actually need.
So, at one end of the spectrum, there is a tiny, tiny, tiny minority of truly genetically short sleepers. And we understand something about the genetics of some of these people. And the shorter sleepers identified still need about 5.7 hours per night on average, and then at the other end of the spectrum, there are people who genetically need substantially more sleep for nine hours. So you need to work out what you need to feel good each day.
And it makes sense to try and work out that need at certain times. So, for example, if you’re going through a period in which you work stress is low and you can extend your time in bed at night, then you can probably start to approximate what that number is for you right now. Or if you’re going on holiday, then if you choose to sleep when you feel like sleeping, within a few days, provided that you don’t consume huge quantities of stimulants and what have you, you probably work out roughly what your sleep need is.
With that said, the amount of sleep that each of us needs on an ongoing basis depends on various factors. So, one of these is exercise. People with higher training loads will probably need slightly more sleep than people without such high training loads. And if you look at the sleep extension studies that, and a lot of them have people aim for about 10 hours in bed per 24 hours, and that could comprise a nap in the middle of the day. If you add in that, then you probably want a nap of either about 20 minutes or about 90 minutes at roughly the hottest time of day.
So maybe 2pm also. It’s probably slightly less than that, but the best time to have is probably around 2:00 pm, and I won’t go into details as to why, but it’s worth bearing in mind. Or you could just have that as one consolidated block at night and aim to get all of your sleep in that period. Likewise, if you have an infection, then you might need a bit more sleep than you would otherwise. Interestingly, infections affect sleep in quite complex ways.
And while a modest dose of some sort of virus, for example, will, if anything, enhance sleep, temporarily, prolong sleep and perhaps increase the proportion of sleep that you spend in the deep stage of sleep. High viral loads will tend to worsen sleep if they surpass some threshold. So finally, it’s also the time of year. If you live at the high latitude, then the photoperiod will vary dramatically between the longest days of summers and the shortest days of winters.
And there have been some really nice camping experiments done by Kenwright at the University of Colorado in Boulder showing that if you take adults and you have them go camping in the Rocky Mountains for a few days and you compare how much sleep they get during winter time, to what they actually get during summer, there’s a dramatic difference between those two. And while initially there’s substantial variation from one person to the next in terms of time investing, within a few days of exposure to natural light only.
So, daylight during the day and then at night, moonlight, starlight and fire. Those individual differences in sleep timing disappear within a few days, such that all of them, quite tightly synchronized with the natural light, dark cycle. And typically going to bed soon after sunset and then wake up right around sunrise, and they’ve also looked at the concentration of melatonin in the blood of most people, melatonin is a neuro hormone produced by the pineal gland that basically signals the biological nighttime to sound throughout your body, telling them to engage in appropriate nighttime activities.
So, it’s clear that the body’s clock is tracking changes across seasons too.
James Cerbie: Excellent. I think the theme there has come up multiple times on the podcast of, we have what the literature says. We have to remember that those are going to be averages based off of population. And when we have the ability to, sometimes it makes sense to treat yourself as an end of one and figure out what you need as an end of one, because the literature is giving us a great starting point that’s going to help mathematically, the largest number of people, but spend time figuring out what you need as an individual because it’s probably going to be a little bit different.
Only other question I have here is, do you have any tech or tools that you like for tracking sleep quality at home that people can use at home? I know the oura ring is really popular. I have one. I haven’t loved it. I haven’t felt that it’s very accurate for me, at least. It’ll be like, hey, you had terrible sleep. And I’m like, not true. I slept fantastic and feel really good.
In my experience. I found it has a harder time when people have low resting heart rates. Their algorithms are probably based off of like swings and heart rate change. And if you have a really low resting heart rate, then the percentage changes will potentially be bigger. But didn’t know if you have any things like that that can help people track their sleep quality. I still personally like the subjective because, you’re going to know. If you wake up, you should know, hey, I slept well or hey, I slept like poop.
Greg Potter: This is a massive subject.
James Cerbie: We do not need to go down this rabbit hole if it’s going to be a huge thing.
Tools to Track Sleep Quality
Greg Potter: I will happily. I just won’t go too far down the rabbit hole, OK? And be somewhat concise for the first time in my life. You have to have a mature relationship with these devices, and what I mean by that is that in recent years there’s been a rise in the number of people turning up to sleep medicine centers, self-diagnosing insomnia on the basis of faith that they’re getting from the wearable devices.
The FitBit says that they spent three percent of sleep period in deep sleep the previous evening. That must be terrible, and on further objective evaluation, using the gold standard ways of assessing sleep, these people are often absolutely fine. The problem is that if people perceive the sleep to be poor on the basis of the feedback they’re getting from the devices, then that’s likely to subsequently affect their performance with respect to outcomes such as cognition and presumably possibly athletic performance, too.
Now, with that said, do these devices have their place? Absolutely. Are they getting better over time? Absolutely. You touched on heart rate there. The way that most of them work is to look at certain measurements. So, one would be looking at heart rate by various means. And heart rate will tell you something about sleep, because as you progressed from stage one on REM sleep to stage two to slow wave sleep, deep stage of sleep, your heart rate will drop.
And then during rapid eye movement sleep, your heart rate will fluctuate quite wildly and be higher than it would be during those deep stage of sleep. So, using that information alone, you can sometimes tell something about sleep. They’ll all say. In some instances, like body temperature, which again varies over
the course of the sleep period. So, if somebody is allowed sleep compared to not being allowed to see, their body temperature will drop more when they sleep.
So based on these different data streams, they try and estimate. Whether somebody is in non-REM sleep, REM sleep or awake. And they’re definitely getting better over time. But for the most part, the models that they use have been trained on healthy people with relatively normal sleep. So, if your sleep deviates from archetypical sleep, then chances are the devices won’t be as accurate for you. Take somebody who has insomnia. They’re lying in bed perfectly still wide awake, but probably scored being asleep.
Take somebody who has restless leg syndrome; they’re fast asleep, but they periodically kick their legs violently during the night, and for some people, they will do this several times each minute for most of the night, but probably be scored as being wide awake when they might be getting eight hours of sleep per night. So, you have to bear that in mind, too. But with that said, if you have relatively typical sleep. And you’re a person who hasn’t necessarily always prioritized, and you can use these devices in a grown-up way and look at the long-term trend in the data, that will tell you something about how your sleep is changing in time, even if the data aren’t perfectly accurate.
So, if you’re going through this period, you’re trying to extend your sleep and your Oura ring is telling you that you’re getting 30 minutes more sleep at night than you were two weeks ago, fantastic. That’s probably meaningful. Other things to consider are the different types of data devices give you. So, while these devices might not be perfect for any one thing, if you are an athlete and you’re interested in your resting heart rate, then your oura will probably give you half decent data about your resting pulse rate.
I say pulse rate because to the heart rate you actually have to measure over the heart itself. And the thing is only a proxy of that. But they will tell you something about your resting pulse rate and your pulse rate variability as well. And those data can be meaningful for athletes in terms of how well rested they are. In particular, if you for some reason are looking to increase your physical activity, take more steps each day, say, wearing some sort of wrist wearables that accurately track steps can be really helpful.
if you are hard charging endurance athlete or explorer and you want to use your common device to work out where you are in the world and how many meters you’ve just ascended, then the devices have utility beyond their applications in sleep alone. And then finally, I’ll just add that there are lots of these devices that the hardware that they use is generally quite similar from device to device quality. The data are probably largely dependent on the algorithms that run in the hardware.
And you should look for something that works well for you. So, if, for example, you’re trying to accurately measure your sleep at home using a wearable device, there probably are a couple of devices that will actually do that now and to look at sleep stages, it’s best to look at certain types of data and the most telling of these data are the patterns of electrical activity in your brain. To look at that, you need electrophysiology.
There are actually a couple of wearable devices now that have electrodes and you wear them over your forehead, and they seem to be quite good at sleep staging. So, one of them is the Dreem 2 Headband. And for somebody who is fascinated by their sleep and has lots of disposable income, I think it’s a great device. It also has an accompanying app which basically uses a modified form of cognitive behavioral therapy for insomnia to help people sleep better.
And it’s got some cool technology, too. So, it uses bone conduction to transmit sounds to people. So, instead of wearing earphones like I am now during sleep, if you want to listen to some relaxing sounds, it will play music or play relaxing tones through your bones using that technology, which is neat. So you have some of those devices which genuinely do seem to be in some instances, comparable. So, again, long answer, yes, they do sometimes have their place, yes, change your subjective experience of your sleep matters.
And truth be told, as a practitioner, I very rarely recommend somebody who’s coming to me with some sort of sleep issue to start using a device or continue using a device because they they generally already are hyper focused on their sleep. And I’m much more partial to using simple questionnaires to help people want to see. And the one I typically use is called the Consensus Sleep Diary. And I think that there’s a website that you can find online that you can use to track your sleep.
I just simply turn it into an Excel spreadsheet and then modify it based on the person. So, if somebody is struggling to sleep because they’re urinating frequently during the night, then maybe they track their urination to see how that’s changing over time in response to whatever interventions we’re using. But something like the Consensus Sleep Diary will give you useful information about your sleep duration, timing and efficiency and so on. That will also let you track your subjective sleep quality, too.
So, yet another long answer, but that is a very deep rabbit hole and I actually only started exploring the surface of it.
James Cerbie: Yeah. Excellent. That was fantastic. Thank you so much. We need to be wrapping up here. I’m just going to throw in one thing super quick for people. So, I think two tools I have used and really like, one is super cheap. You can go on Amazon and buy; it’s around ten bucks. Blue blockers, I think are an incredibly easy no brainer. If you are going to be getting light exposure as the sun’s going down, it gets dark.
Blue blockers are just such an easy thing to throw on at like eight o’clock at night. I usually put mine on like an hour before I want to be in bed. And then my sleep is almost one hundred percent dependent upon temperature. If it’s cold enough, I sleep like a baby, guaranteed. So, I have a thing called a chili pad, which I absolutely am in love with. It’s like one of my favorite things I’ve ever bought. A little more expensive than the Blue Blockers, but it runs cold water basically.
You put this mat on your bed. It goes underneath your sheet, and it runs cold water underneath it so that it keeps you cool within your bed, and you don’t get super hot there under the covers, but I’ll throw links to both of those in the show notes. And then this was amazing. Thank you so much. I hope everyone listening enjoyed this as much as I did. Where can people go to find you if you would like to be found?
Where to Find Greg Potter
Greg Potter: I do want to be found. But check out resilientnutrition.com because we’re not just a company that sells food products. There is also what I hope is a lot of helpful content there. For example, there is an e-book that’s freely available in the principles of resilient nutrition I wrote, that you can download. And we haven’t spoken about nutrition much today, but a lot of people have found that really handy. There are also guides on nutrition for certain types of events, blogs and so on.
And then we are @resilientnuts on the social media. And then personally, my social media handle is @gregpotterphd because I’m not a real doctor. And you can reach out to me there if you just want to send me a message about something, no worries.
James Cerbie: Thank you again, man. Everybody listening. Hope you guys enjoyed this. Have a beautiful week and we’ll be back next Monday.
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