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The Definitive Guide To Sleep | Dr Greg Potter

Dr Greg Potter is a PhD graduate at the University of Leeds & Content Director at HumanOS. His research focus is on sleep and chronobiology; looking at circadian rhythms, light-dark cycles and the potential for meals to entrain peripheral circadian clocks. The unsung hero of health is hiding under our pillow every night and today we learn just how important a good night's sleep is to our short & long term fitness, our mood, cognitive output, physical performance, injury risk, weight and pretty much everything else. Discover the best approach for dealing with sleep deprivation, how to optimise your sleeping environment, how meal content & timing can affect our circadian rhythms and a lot more. Further Reading: Follow Greg on Twitter: https://twitter.com/gdmpotter $1 for 1 month of Premium Membership at: https://www.humanos.me/ (Code: modernwisdom) - Listen to all episodes online. Search "Modern Wisdom" on any Podcast App or click here: iTunes: https://itunes.apple.com/gb/podcast/modern-wisdom/id1347973549 Spotify: https://open.spotify.com/show/0XrOqvxlqQI6bmdYHuIVnr?si=iUpczE97SJqe1kNdYBipnw Stitcher: https://www.stitcher.com/podcast/modern-wisdom - I want to hear from you!! Get in touch in the comments below or head to... Twitter: https://www.twitter.com/chriswillx Instagram: https://www.instagram.com/chriswillx Email: modernwisdompodcast@gmail.com

Chris WilliamsonhostDr Greg Potterguest
Aug 27, 20182h 3mWatch on YouTube ↗

EVERY SPOKEN WORD

  1. 0:00 – 15:00

    (wind blowing) Hi, friends. How…

    1. CW

      (wind blowing) Hi, friends. How was your night's sleep? Was it good? Hopefully after today's episode, it's going to be better. Today, we're going to speak to Dr. Greg Potter, who is a PhD graduate from the University of Leeds, and a specialist in sleep. His work has been featured absolutely everywhere, from Reuters to Time Magazine, Washington Post, USA Today, Daily Telegraph, BBC Radio. He's, um, he's pretty prolific. Uh, and he's also the content director at HumanOS.me. Now, the guys at Human OS haven't sponsored this, uh, episode at all. However, it is a fantastic service that you should check out, and later on in the episode, Greg explains what it's all about. But if you do want to go and have a look, it's free to sign up, and with the code "modernwisdom," you can actually get their premium version for a dollar for the first month, and there's no minimum term. So, check it out. Now, many people take a lot of time researching their diet or their exercise and making sure that they're trying to live a healthy life. But quite a lot of us overlook just how important sleep is in this equation. And having read Matthew Walker's book, Why We Sleep, I was struck by just how little care I was giving to my sleep habits. The implications on your health, mood, and performance, both in the short and long term are pretty drastic, and I don't think that there can be enough weight applied to just how important sleep is. Now, hopefully today, we're gonna convert you from a nonbeliever to a sleep paragon who is armed with some new tools to improve their sleep and a passion to actually make it better. Essentially, what I'm saying is that if you live a long and healthy life with all of your faculties still intact, at the ripe old age of 95, you can be on your deathbed incredibly mobile and full of zen and look back at this podcast and think, "Thanks, Chris and Dr. Greg." (upbeat music) Dr. Greg Potter, welcome to Modern Wisdom.

    2. GP

      Thanks very much. It's great to be here.

    3. CW

      How are you today?

    4. GP

      Yeah, I'm very well. How are you?

    5. CW

      Uh, fantastic, thank you. Did you get a good night's sleep?

    6. GP

      Not bad. I've been up for a while.

    7. CW

      By- by whose standards did you have a not bad night's sleep?

    8. GP

      By my own not particularly good standards right now.

    9. CW

      (laughs) Rigorous sleep standards, right?

    10. GP

      Well, I don't set the bar too high, but the last few weeks have been a bit ropy at times.

    11. CW

      Is it do as I say, not as I do?

    12. GP

      Yeah, it's one of those. (laughs)

    13. CW

      (laughs) Um, so can you explain to the listeners what your speciality is, what your, um, what you focus on in your research area?

    14. GP

      Sure. So, I have just passed my PhD, which was-

    15. CW

      Congratulations.

    16. GP

      Thank you very much. Which was at the University of Leeds, and I'm in Leeds right now. And during my PhD, I focused on sleep, diet, and metabolic health in UK adults. So, I focused on studies of human beings, and in my PhD, there were several different parts. It began with the validation of a dietary recall method. So, if a nutritionist is interested in how diet affects health and risk of various diseases, then they need accurate ways of capturing what somebody eats. And to that end, you need to validate the tools that you use, and I was involved in the validation of one of those tools, which is called myFood24. And it's the first validated tool designed for use specifically with adults in the UK. It's very comprehensive, and that paper is just being published. And I then used that dataset to look at associations between when people eat relative to when they sleep and their metabolic health. I also did some work looking at how sleep duration is associated with risk markers that are associated with diabetes in the UK and also with how people eat. And then at the end of my PhD thesis, I did a randomized control trial of long-term melatonin supplementation among people who are at high risk for type two diabetes. So, let's say, for example, Chris, that your dad has type two diabetes. That would increase your susceptibility to that disease.

    17. CW

      Mm-hmm.

    18. GP

      Question was, can you use melatonin as a prophylactic agent against you developing type two diabetes? So, just wrapped all of that stuff up and now I work for Human OS as content director and have been working with those guys for about the last 18 months or so, and have more or less been working full time for the last four months.

    19. CW

      Mm-hmm.

    20. GP

      And the CEO also has a strong background in sleep research, so we share that in common, but we're very-

    21. CW

      You're in good, you're in good company then.

    22. GP

      Yeah, I would say so. For sure.

    23. CW

      That's fascinating. I mean, there's, there's an awful lot, (laughs) an awful lot to go through there, but I know that a lot of the people who are listening will have heard me mention a number of times Matthew Walker's book, Why We Sleep.

    24. GP

      Yeah.

    25. CW

      Um, I think that's probably up there with my most ever listened to podcasts between him and Joe Rogan. And it's gonna be, it's gonna be really, really interesting to be able to dig into what I've...... heard, um, and, and read about so much and, and try and actually, um, elicit some of the answers that I think are maybe missing from my body of knowledge, and then give the listeners a little bit more, uh, a little bit more of an understanding of why sleep's important and, and, and what it does to people. And then I'm super excited to talk about Human OS as well. I, earlier on today, had a, a pretty comprehensive browse of the, uh, of the site, so we'll be able to finish up with that at the end, so a lot to get through today.

    26. GP

      Smashing. Sounds good.

    27. CW

      Fantastic. Um, so to get started, do you know why we sleep?

    28. GP

      No, not really.

    29. CW

      (laughs) That's great.

    30. GP

      So it's a longstanding question in sleep research, and there are many different ways that you can try and address it. What I would say is that there's no real consensus right now, and I think it's worth thinking about why we sleep from an evolutionary perspective. And when you think about sleep, and this is something that Matt discusses at length and with great clarity in his book, sleep's very strange in that while you're asleep, you can't eat, you can't gather food, you can't have sex, and you're vulnerable. And for all of those reasons, there should have been very strong evolutionary pressure against the development of sleep-like behavior.

  2. 15:00 – 30:00

    Mm-hmm. …

    1. GP

      crisis in science recently, and it's received an awful lot of attention in the media. I think psychological research in particular has come under fire for the inability to reproduce the results of previously done studies. And what's nice now is that more and more journals are necessitating that people make their data open access after publishing so people can revisit what other scientists did-

    2. CW

      Mm-hmm.

    3. GP

      ... to make ... that they did in fact do what they said they did and to make sure that they haven't dredged through their data and tried to come up with a way of analyzing their data to support their hypothesis rather than going in there beforehand and saying, "Okay, this is how I'm gonna look at my research question, and regardless of what the results are, I'm sticking to my guns."

    4. CW

      Well, that's the, that's the scientific principle, right? You shouldn't be trying to make the research fit a, a previously held hypothesis. That's not the way that it's supposed to be, but I can imagine that a lot of people, once they've got their teeth ... once they're certain about something conceptually, they want the research to then reflect that.

    5. GP

      Yeah, and an issue is that it's difficult to publish negative findings in scientific journals. By negative findings, I don't mean that they're disheartening or anything like that.

    6. CW

      Mm-hmm.

    7. GP

      I mean there's no effect of A on B.

    8. CW

      Yeah.

    9. GP

      And, if-

    10. CW

      It's less, it's less glitzy, right? It's not as much of a ... Melatonin doesn't, doesn't affect, um, sleep quality isn't as much of an exciting title. Oh, that might actually be, but (laughs) something else that A doesn't affect B, it's not as attention grabbing, right?

    11. GP

      Yeah, it's not gonna get on the front page of The Washington Post anytime soon.

    12. CW

      I got you. So we understa- or we have a beginning of an understanding of what we think sleep is required for from an evolutionary perspective. Do we know how much is optimal? Is there a, an agreed upon time? It's kind of this wives' tale anecdote that eight hours is how much we need a night. Is that, is that correct?

    13. GP

      There are guidelines, but you can't take the guidelines and assume that you're correct, th- th- that they are correct for you as an individual. The guidelines vary according to how old somebody is. So if you look at young people, they need more sleep than adults, and for adults, according to the National Sleep Foundation, on average, we need seven to nine hours per night. But there is relatively substantial variability between people in sleep need. And one other thing that I'll add is that the amount of sleep that you need is a moving target. So I don't know what your experience is, but for me, for example, I generally find that I sleep more in the winter than I do in the summer, and I think that's probably somewhat related to the photoperiod.

    14. CW

      Mm-hmm.

    15. GP

      Also, if I'm going through a period in which I'm exercising particularly intensively, then I'll need more sleep. If I have a cold, then I'll need more sleep. If I'm stressed about something and I have a deadline on the horizon, then it's just as if the alarm clock in my brain just comes online a little bit earlier.

    16. CW

      Yeah.

    17. GP

      And for that reason, invariably I, I sleep less. So even though we have these generic targets, I think that actually fundamentally-... you give yourself the opportunity to get the sleep that you need by getting in bed on time. You focus on preparing for sleep as well as possible by getting in the right frame of mind, and also supplying with- your body with what it needs, ensuring that your environment around you is conducive to good sleep. And then you don't wake up to an alarm and you see how long you sleep. And it- it sounds facile to-

    18. CW

      (laughs)

    19. GP

      ... explain that way, but I- I do think that that is how it is. With all of that said, seven to nine hours is a good baseline for most people, and we understand more and more about some of the things that do influence why some people need more or less sleep. But some people, I think historically, have thought that there are those lucky few out there, the Margaret Thatches of the world, who need three hours of sleep and they function just fine, and that just doesn't seem to be the case.

    20. CW

      Mm-hmm.

    21. GP

      So of all of the genetic variants that have been identified so far, the particular variant that's associated with the shorter sleep phenotype is on average a variant that has adults sleep about 6.2 hours per night, which I think is probably far more than most people would expect the shorter sleepers to sleep.

    22. CW

      Is that the phenotype which is present in the same percentage of people that get hit by lightning? Is it the incredibly rare one?

    23. GP

      Yeah, that sounds about right, yeah.

    24. CW

      (laughs) Is it like, I think it's one in a hundred and twenty thousand or something like that.

    25. GP

      It's very rare, yes.

    26. CW

      (coughs) Right. So I think it's safe to assume that you don't have that (laughs) phenotype for the vast majority of people that are listening. So what that means is you need to be aiming for between seven and nine hours.

    27. GP

      Mm-hmm.

    28. CW

      And just how important is sleep to our short-term and long-term health?

    29. GP

      That's a very big question. (laughs)

    30. CW

      (laughs)

  3. 30:00 – 45:00

    Okay, so that's what…

    1. GP

      It also uses things like changes in body temperature each day. Another very important hormone in the circadian system is cortisol. And if you look at the daily rhythm of cortisol, then in anticipation of waking each day, you see this big spike in cortisol in healthy people, maybe an hour or so before waking up. And what that does is mobilizes stored energy reserves in things like your muscles, it increases your blood pressure, your heart rate, and it readies your body for the day ahead. So that's one other key agent. And then the master clock itself also sends out or secretes its own...... substances that then reach other areas of the brain and help coordinate the timing of all these different body systems. So, the circadian system as a whole optimizes your body for the needs of the present moment and in this way, for example, you will be at your strongest during the daytime. Your digestive system is best set to digest food during the active period and, at nighttime, your appetite will naturally wane. You'll have a drop in core temperature and brain temperature, and that improves your ability to fall asleep. You will see a spike in growth hormone, which will help you preserve your lean body mass overnight. And overall, the net effects of this symphony, if you like, is to make sure that if everything is working properly, then your whole body is optimized for the needs of the present moment.

    2. CW

      Okay, so that's what circadian rhythm is. I'm gonna guess that that, um, that requirement for light and dark to regulate our sleep is why seasons, specifically in places like the UK where we do have quite a big disparity between summer day lengths and winter day lengths, I'm gonna guess that that's one of the reasons that people may struggle to wake up in the morning or may find sleep different, uh, between seasons. Is that right?

    3. GP

      Yeah, it is. And there's not actually very strong evidence of seasonal differences in people's sleep patterns in art- in artificially lit environments because everywhere you go in the UK, you can't escape a streetlamp-

    4. CW

      Yeah.

    5. GP

      ... or light from buildings or whatever. But if you take people and you have them go camping during the winter and you have them go camping during the summer, then you will, you will see quite rapid changes in people's sleep patterns that track changes in the light-dark cycle. And one thing that you mentioned there, which is relevant to mood disorders, to circle back to that, is how that changes over time and how some people may find it hard to wake up at certain times of year or just feel worse. So seasonal effective disorder, for instance, is quite commonplace, and it's more commonplace the further from the equator that you move, so at higher latitudes. And what you find is that around the time that we transition and the clocks switch back each autumn, you tend to see a spike in people who report experiencing depression at those times. And actually, the circadian system is a point at which you can intervene in order to try to help those people. So-

    6. CW

      Do you think that that's, do you think that the reports of depression are to do with the single night of l- lack of sleep or that that is a marker that the days are getting to a, a length where that would occur?

    7. GP

      Yeah, I, I think it's probably a bit of both because-

    8. CW

      That's crazy that a single, a single change in time would elicit a, a response from, you know, a general population.

    9. GP

      Yeah, I, I, I think the strongest evidence of the change in time producing that kind of response is daylight savings time. So, during the springtime when we lose an hour of sleep each year, you tend to see a spike in traffic accidents at that time of year, for example. There's also some relatively weak evidence that you might see an increase in cardiovascular incidents at that time. So an increase in things like heart attacks.

    10. CW

      Off the back of one night?

    11. GP

      Well, it's, it's one night acutely, but of course, people have to keep waking up early.

    12. CW

      Mm-hmm.

    13. GP

      So let's say that the first night you lose an hour of sleep, and then you start to adjust to being a little bit earlier, but you never fully adjust. So maybe the second week you're losing 45 hours of sleep.

    14. CW

      Mm-hmm.

    15. GP

      And the third week, you're losing 30 minutes of sleep and, and so on.

    16. CW

      Yeah.

    17. GP

      I think that there's, there's a cumulative effect there over time. So I think that's, that's probably the best evidence of that type of acute disruption to sleep having long-term consequences for lots of people. But also, there, there is this change in photoperiod that seems to independently affect risk of people experiencing certain things. And-

    18. CW

      Okay.

    19. GP

      ... and I think particularly up at, up at the poles, people are at very high risk for that.

    20. CW

      Yeah, definitely. I mean, there's periods, entire months where the sun doesn't set.

    21. GP

      Yeah.

    22. CW

      If, if you were ever (laughs) , if you were ever gonna be somewhere and suffer with seasonal affective disorder, it's gonna be, it's gonna be either of the poles. So, um, going back to moods, um, have we... Uh, is there any research which shows a link between someone with sleep l- uh, uh, sleep deprivation and depression?

    23. GP

      That's an interesting question because actually, historically, sleep deprivation has been used as an antidepressant.

    24. CW

      Really?

    25. GP

      Yeah, a single night of sleep deprivation. So quite often it's the case that people with depression will experience poor sleep, and if you deprive somebody of sleep over one night, then they have this really strong increase in the pressure to sleep, and then in subsequent nights, they sometimes find it easier to get back onto some sort of consistent sleep schedule, so-

    26. CW

      Like wiping the Etch A Sketch board clean, so to speak.

    27. GP

      Kind of, yeah. But, but also during that night of sleep loss, people's mood does tend to improve acutely, and we don't really understand fully why that's so. I haven't looked closely at that research. I know that somebody who I've collaborated with at University of Surrey has published some work on that, and they looked at the metabolome, which is where you basically take a biological sample, so let's say you take somebody's blood...... and you look at all of the metabolites that are in that blood sample at that particular time of day, and you can take them at various points during the day and look at how the metabolites respond to various interventions, so for example, diet or sleep loss. And if you look at the effects of sleep loss, and I think that there's evidence that you see changes in serotonin signaling, serotonin metabolites, and serotonin's a neuromodulator, neurotransmitter, which is important to things like mood and sexual function, motivation, all sorts of things. But I think that the strongest evidence, of course, that serotonin is critical to that is the fact that what's the most common antidepressant medication people use? It's-

    28. CW

      SSRIs, yeah.

    29. GP

      ... reuptake inhibitors, which basically prolong the a- the amount of time that serotonin is in the synapse between neurons in the brain, a bit- reduce the clearance of the serotonin from those. So sleep deprivation does have these short-term antidepressant effects, but those effects aren't sustained over time, and actually, uh, as I alluded to before, what you tend to see is that over the long term, of course, worse sleep is associated with poor mood. Uh, the tricky thing, as I, as I briefly touched on, is just that often somebody sleeps poorly, but how do you causally tie that to some specific outcome in an observational study when people who sleep poorly might be smoking more, they might experience more stress at home, perhaps they drink, they have all of these other lifestyle behaviors that negatively affect the e- the health outcome in question?

    30. CW

      Yeah, it's very difficult to isolate, right?

  4. 45:00 – 1:00:00

    Somnogens? …

    1. GP

      But almost everything does seem to be affected. The question is that, the question is what i- what is it about shift work that predisposes people to that? Because it's a complex exposure scenario in which it's not just sleep that's disrupted or circadian rhythms that are disrupted. You also have people doing all of these things and of- often working stressful jobs, for example, that will also affect their risk of various diseases. So that's all, that's all-important to understand. One thing just to circle back to why when you sleep affects the quality of your sleep is that if we look at how sleep is regulated, then there are two processes. And one of those processes influences how awake you feel at any given time. That's regulated by your circadian system. And what happens is that each day you wake up in the morning and then over the course of the day you see this increase in the drive to stay awake, and then around the time that you normally fall asleep, there's a sudden drop in this wakefulness drive. The other process is the sleep process, and that's the process that builds with prolonged wakefulness. So the longer that you've been awake, the more sleepy that you are. And that's not a perfectly linear effect, but that's true to some degree. And there are various physiological correlates of that, and these are called somnogens. You can think of them as chemical barometers of how long you've been awake. So as I'm having this conversation with you, these are accumulating in our brains right now and they're increasing our pressure to fall asleep.

    2. CW

      Somnogens?

    3. GP

      Yeah.

    4. CW

      That's som-

    5. GP

      Exactly. And if you look at shift work, and let's say that somebody does a slam shift, so they're used to being up during the week and then they have a single night shift. They get in at 5:00 AM and for the last five days, they've been waking up at 6:00 AM. What that means is that whereas at 10:00 PM the previous evening they had the sudden drop in wakefulness drive and they were desperately trying to stay awake at the start of their night shift-

    6. CW

      Mm-hmm.

    7. GP

      ... now at this time of day at which they're trying to fall asleep, they're just starting to enter a period where the wakefulness drive is increasing.

    8. CW

      So is there a, there's sort of a lag but with the, this sl- sleepiness, the somnogens and the, the wakefulness drive, there's a lag behind what's actually going on. It's got, like, a, a delay on it for it to catch up.

    9. GP

      So there's this, there's now this big pressure to sleep because of the accumulation of these somnogens in the brain-

    10. CW

      Mm-hmm.

    11. GP

      ... but they've missed that opportunity to sleep the time in which the wakefulness drive was very low. So they've got this combination of an increasing drive to be awake, but also very high sleep pressure. And for that reason, it's not, it's not quite as easy to fall asleep as it would have been otherwise. But let's say that they do fall asleep. What will happen is that as they enter sleep, the wakefulness drive is still increasing and they're starting to pay off all of that sleep debt that they've accumulated. So as somebody falls asleep, all of those somnogens that are accumulating in the brain are then paid off back to normal levels. So over the course of a good night of sleep, what should happen is that the brain is restored, you wake up next day and you've got this big increase in alertness because you now have an increasing wakefulness drive and you've paid off all of the sleep debt. The problem is that now these people, they're going to sleep at 6:00 in the morning and they're starting to pay off all of that sleepiness from the previous day, but they've got this wakefulness drive which is kicking back in, so now they're experiencing an increasingly strong wake drive and less and less sleep pressure. What happens? They can't stay asleep. So maybe they get a couple of hours into their sleep episode and they just can't consolidate it and for-

    12. CW

      Yeah, I've, I've certainly, I can certainly attest to that.

    13. GP

      ... you know, there's, there's sleep fragments. And if you pull an all-nighter and don't even try to go to sleep, let's say that you just, you go out and you're promoting your event. You get in and you just think, "I'm not sleeping tonight," what you'll experience over the next day is that how sleepy you are doesn't just build predictably over the course of that day. It waxes and wanes.

    14. CW

      Yeah, it comes in waves.

    15. GP

      Yeah, and, and around lunchtime we have this so-called post-lunch slump, and I think a lot of people historically have thought that that's the result of eating a big, heavy lunch, and that's not really the case. What-

    16. CW

      Is that's- it's- there's a, there's an argument that this is due to an evolutionary, um, biphasic sleep, um, tradition. Is that right? Or there's some people who've claimed that?

    17. GP

      Yeah, there are some people that have claimed that, and you do see that in certain groups of people who haven't been affected by the effects of industrialization yet. So, if you look at the hunter, hunter-gatherers, for example, then what you see with them is that during the winter, they have monophasic sleep.

    18. CW

      Mm-hmm.

    19. GP

      So, all of their sleep is consolidated in one nocturnal bout each night. But during the summer, they have a siesta.

    20. CW

      So the Spanish, the Spanish have got it right?

    21. GP

      Well, it's qu- it's quite interesting in that Spain is a lot warmer than somewhere like the UK, and the Spanish have their siestas at lunchtime when it's hot. They get out of the sun and they take advantage of that post-lunch slump, and meanwhile, it's not quite so hot here and we carry on about our working days. So anyway, some people do seem to naturally have that pattern. I think if you're consistently in the habit of, of sleeping in that way, then it's a perfectly healthy way to go. But also, what I would say is that if you're not used to that particular pattern, then during that lunchtime nap, you'll see a reduction in the pressure to sleep as you fall asleep. And what that means is that when you then try to fall asleep that evening, you might have a harder time nodding off.

    22. CW

      Yeah, I could, uh, I can definitely attest to that as well. So, to give you some, um, th- this is, this is probably like patient zero for bad sleep for you, but I'll, uh, I'll give you the, the example anyway. Very typically for me, if I've got a long day in the office followed by a trip to Manchester from Newcastle to run one of our events, I'll wake up at maybe, I'll try and push my waking time a little bit further back, so I'll wake up at 9:00. I'll work, and then I have to drive back from Manchester to Newcastle. I'll go to bed at 6:00 AM, and then looking at my clock, I'll think to myself, "24 hours from now, I'm gonna want to be getting up because it'll be a Monday and I'll want to start my week on a good note." But that means that at 6:00 AM on Sunday morning, I need to fall asleep, wake up, fall asleep, and wake up in the space of 24 hours. And, you know, as much as, like, getting up and getting after it can be viewed as an admirable quality in a 21st-century, um, corporate society where, you know, everyone's trying to be successful, it doesn't sound like that's the best thing for, for my health.

    23. GP

      No, it probably isn't.

    24. CW

      (laughs)

    25. GP

      But it's unavoidable in that particular scenario. So, the question is, what do you do to cope with that sleep loss? And I think that what you try to focus on is getting some sleep and coping with the sleep loss during the way, but doing so in such a way that you don't interfere with your ability to fall asleep the following evening. And another thing to consider is that you can try and preemptively prepare for those episodes by banking sleep beforehand. So, banking is an apt analogy here, in that, let's say that you're trying to accumulate a certain amount of wealth in the coming week and each minute of sleep that you get represents one, one pound, okay?

    26. CW

      Mm-hmm.

    27. GP

      This week, you try to, to bank as many pounds as possible by getting as many minutes of sleep as possible, knowing that next week you're not gonna get that much sleep, and subsequently, next week you're gonna be in debt. So, that- that's how you try to prepare for it. So, with you, Chris, let's say that you've got a really good week this week, and you can, you can try to be consistent in your patterns knowing that next week you've got several events.

    28. CW

      Mm-hmm.

    29. GP

      That will help protect you in certain ways against the negative effects of the sleep loss that you will experience the next week. It's h-

    30. CW

      That's crazy. So it, it is, it is literally like a savings account.

  5. 1:00:00 – 1:15:00

    (laughs) …

    1. GP

      that would get on the front page of The Washington Post because it was novel, but it wasn't replicated. And what they did is they shone light on the back of somebody's knee, I think-

    2. CW

      (laughs)

    3. GP

      ... during the day, and, and supposedly it was able to shift the timing of the circadian system.

    4. CW

      Okay.

    5. GP

      And it... it hasn't been shown since. So as far as I'm aware, that's not the case. I know that there are these devices now that do things like shine bright lights in your ears and-

    6. CW

      Yeah, there's all, all kind of weird and wonderful, uh, sleep aids now, isn't there?

    7. GP

      Yeah, and, and not just for sleep, because light actually has a variety of other effects, they're non-image-forming effects, but effects that are... either relates to the circadian system or they have effects on things like cognition. So bright light exposure during the daytime routinely will acutely boost someone's mental performance if they haven't been exposed to bright light before that. And that's why actually one of the ways to cope with sleep loss that we'll come to is making sure that you spend some time outside. So that is part of the picture, but these devices anyway...... that shine-

    8. CW

      The shining lights in your ears.

    9. GP

      Yeah, I'm, I'm, I'm not sure about them. I haven't looked close at the research.

    10. CW

      You don't have a pair?

    11. GP

      I don't have a pair.

    12. CW

      (laughs)

    13. GP

      No. And I, I'm not aware of any sleep researchers that seem particularly persuaded by their utility. I'll put it that way.

    14. CW

      Okay. So I mean, there's, there's definitely a, um, going back to a couple of Ben Greenfield podcasts that I've heard and a, a few other anecdotal bits of evidence, people that go into hotel rooms and will put tape over, uh, microwave and air conditioning LEDs and stuff like that, because even if they've got a, they've got their sleep mask with them, they're not happy with the darkness of the room.

    15. GP

      Yeah, I, I, I think that a lot of that is overkill.

    16. CW

      Is that sweating the small stuff?

    17. GP

      It's, it's sweating the small stuff and the point actually is that these photoreceptors in your eye that are involved in the regulation of your circadian system are quite sluggish. They, they keep a track record of your light exposure over the course of the day. They don't respond very acutely to it. So if you spend lots of time outside during the daytime, have lots of bright light exposure, which is of a blue wavelength in particular, then a little bit of light exposure at night from a microwave is a drop in the ocean.

    18. CW

      Yeah.

    19. GP

      It, it just won't shift your system. With that said, if you'd been in complete darkness for the previous 16 hours and then you went to the toilet and you switched the light on when you went to the toilet, then that actually probably would shift a phase of your circadian system.

    20. CW

      That's interesting. So you kind of become, your sensitivity to light is increased based on what the, the most recent period of your day has been like?

    21. GP

      Strongly so, yeah.

    22. CW

      That's crazy. That's, I, I guess for, uh, people in certain professions, that's going to be a, a very important fact for them to take away.

    23. GP

      Yeah. Uh, it has, it has strong implications for, for shift work and for things like jet lag too, because you have situations in, in which you want to go to shift work, for instance, but y- y- you're just there for one evening.

    24. CW

      Mm-hmm.

    25. GP

      You need to adapt to it.

    26. CW

      So did you, you referred that, referred to that as a slam shift?

    27. GP

      Yeah. Yeah, and you've got all these different shift work schedules, and in some instances, particularly in remote environments, people will want to go somewhere and they will always be on night shifts. And in those rare circumstances, you want to fully adapt your circadian system and all you do then is you manipulate your environment such that you make that as easy as possible and you don't go outside. (laughs)

    28. CW

      (laughs)

    29. GP

      That's, that's, that's not most people.

    30. CW

      Yeah.

  6. 1:15:00 – 1:27:46

    Do you have a,…

    1. GP

      the over-the-counter sleep aids that you can take.

    2. CW

      Do you have a, do you have a list of ones that are, um, Dr. Gregg Potter approved?

    3. GP

      (laughs) I'm not going there. (laughs)

    4. CW

      Oh, do you, do you have a list of ones which you use or would use?

    5. GP

      Well, this, this isn't advice. To be very-

    6. CW

      This is not advice. Okay, to be incredibly clear to everyone who's listening, this is a hypothetical situation.

    7. GP

      This is not advice and it's, so probably actually not what I would take if I had access to sleep drugs because many of them are only available under subscription.

    8. CW

      Okay.

    9. GP

      Under prescription, sorry.

    10. CW

      Yeah.

    11. GP

      So, you can get diphenhydramine over the counter, which is just the stuff that's in Nytol and that is what's called an inverse agonist to histamine H1-receptors in the brain, which just means that instead of just blocking the interaction of histamine with its receptors, histamine is a wake-promoting neuromodulator and instead of just blocking that interaction, it actually has the opposing effect and diphenhydramine seems to help people fall asleep a little bit faster and stay asleep slightly longer and it is available over the counter. The recommended dose is 50 milligrams in the research, you can really buy it in 25 milligram tablets and they'll say start with that.

    12. CW

      Yeah.

    13. GP

      And increase your dose up to a maximum of 50 milligrams. So I think that can be useful. The problem with all of these things is that when you target one particular neuromodulator in that way, you can quickly produce dependence and withdrawal symptoms too.

    14. CW

      Yeah. Yeah.

    15. GP

      And actually, it's funny because there's a discordance between people's perceptions of natural substances and medications, so people will often resort to herbal sleep aids thinking, "Oh, it's natural, it must be safe." If they're targeting the same chemical pathways in the brain, then just because something is from a plant, it doesn't mean that it's magically gonna be okay and that it's, it's gonna have fewer negative consequences than its synthetic counterpart.

    16. CW

      The potential for it to carry along with it some byproducts that might have unintended consequences as well is probably a little bit higher than something that's been synthesized purely for the purpose of being that, that particular pure compound.

    17. GP

      How, how well regulated is the supplement industry?

    18. CW

      Uh, incredibly not. (laughs)

    19. GP

      (laughs)

    20. CW

      But the drug industry is als-, well, debatably, but at least a little bit more, I think.

    21. GP

      Yeah.

    22. CW

      Um, so what about, and I'm gonna touch on it because I was recently in America-

    23. GP

      Mm.

    24. CW

      ... and this is, this, this seems so widespread I knew that I was gonna have a sit down with you, so I wanted to ask some people. Um, of a group of, uh, five men and 10 women that I was sat around a table with which is definitely not a representative sample but, um, 10 out of the 15 of them all use melatonin every night and all of them reported using the tablets at least, uh, a couple of times per year.

    25. GP

      Okay.

    26. CW

      The tablets that they were referring to mostly were sublingual ones which, uh, dissolve under the tongue. I know that melatonin isn't available in the UK so this may be a supplement that a lot of people who are listening have never tried-

    27. GP

      Mm.

    28. CW

      Um, have you had a look at much research to do with melatonin? Uh, I, the, I guess it's external melatonin or...

    29. GP

      Yeah, I have, well, the, the final chapter of my PhD was, was on this topic.

    30. CW

      Oh, well you, you, you should, you should, uh, know a little bit about it then.

Episode duration: 2:03:10

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