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Dr Rangan ChatterjeeDr Rangan Chatterjee

#1 Sleep Neuroscientist: Do This Every Morning To Stop Decline & Stay Young | Russel Foster

Prepare to learn everything you wanted to know about sleep (but were too tired to ask). For today’s episode I’m welcoming back Professor Russell Foster, one of the world’s foremost experts on circadian rhythms and sleep.

Dr. Rangan ChatterjeehostRussell Fosterguest
Feb 7, 20242h 4mWatch on YouTube

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Transcript

  1. 0:00 – 3:20

    Sleeping separately without harming the relationship

    1. RC

      I wanted to start off by talking about something that is often not discussed, I think, when it comes to sleep, and that's the issue of partners-

    2. RF

      Mm

    3. RC

      ... sleeping in the same bed.

    4. RF

      Yeah. I... Do you know, it's interesting, I, I was talking about this fairly recently, and, and I've talked about it, I think, in the book too. And I'm saying that, look, if you find it difficult to sleep with your partner, then, and if you can, find an alternative sleeping space, because it's no reflection upon your relationship. If your partner snores, for example, or the bed is too hot, or if they wriggle around a lot, find an alternative space. And in fact, it's not the end of a relationship. And so many people have come up and said, "Oh, no, I couldn't possibly sleep in a separate bed. It's the... It marks the end of a marriage." It doesn't. It marks the beginning of a new, wonderful phase in your relationship, 'cause you both get decent sleep. Um, you don't resent somebody sort of jabbing you in the ribs because you're snoring or whatever. And you can have nice little rituals of, of, of getting together in the morning to have a cup of tea or whatever. So I don't see the problem at all, but there is that psychology that, oh, you know, it's, it's you've got to sleep together. Don't agree with it.

    5. RC

      Mm-hmm. If I think about the UK or the US, I would imagine that in these countries and cultures, there may be a bit of pushback-

    6. RF

      Oh, yes

    7. RC

      ... and go, "No, no, if you're in a couple, you sleep in the same bed."

    8. RF

      Yeah.

    9. RC

      But I imagine there's many cultures around the world where this is not the case.

    10. RF

      That's true. Um, a-and, and it, it, it... There's a whole spectrum. So I, I remember when I first went to Germany, as, with, with my wife, and w- we, we were given this fantastic room, huge bed, but separate duvets, which is a really smart thing because often the, the temperature ranges for, for, for couples will change. So separate duvets is a really easy solution to that. Snoring is, of course, a lot more problem- problematic. But, but also in cultures like Japan, um, it's very frequent that the children sleep with the mother and the father sleeps separately.

    11. RC

      Mm.

    12. RF

      So there's, there's every sort of, um, relation- and of course, the aristocrats, um, it was always, you know, they always had separate, separate bedrooms.

    13. RC

      Yeah, it's interesting. I was chatting to one of my best mates about this recently, and he's a spinal surgeon on the south coast of England. And he said to me, "Mate, no way. That's the start of the end-

    14. RF

      Yeah

    15. RC

      ... if you don't sleep in the same bed-

    16. RF

      Mm

    17. RC

      ... as your partner." That's how ingrained it is.

    18. RF

      Yes.

    19. RC

      But I guess let's look at the flip side. In our first conversation, we discussed together how poor sleep has so many impacts-

    20. RF

      Yes

    21. RC

      ... on our short-term and long-term health. And if we just think about the short term, poor sleep leads to less compassion, less empathy, um-

    22. RF

      Reduced sense of humor. I mean-

    23. RC

      Reduced sense of humor

    24. RF

      ... boy, you need humor in a relationship. [laughs]

    25. RC

      Yeah, so by that logic, of course, if sleeping in the same bed is resulting in one or both parties not getting enough sleep, which means you have less empathy, less sense of humor, less tolerance to a whole host of different things-

    26. RF

      Yeah

    27. RC

      ... it kind of stands to reason if you have the space, and of course not everyone does-

    28. RF

      That's the issue. Yeah

    29. RC

      ... right, if you have the, the space and the capability, it might actually improve your relationship.

  2. 3:20 – 6:20

    Snoring vs obstructive sleep apnea: what’s benign and what’s serious

    1. RF

      I, I... That's how I would argue it, absolutely, yes. Now, you have to be slightly careful because what you want to make sure that your partner doesn't have obstructive sleep apnea. So this is where the musculature of the neck will, will, uh, uh, uh, will, will collapse and, and block the airway. And so they'll be sort of snoring away, and then they'll just stop. And then they'll wake themselves up. The brain realizes it's been deprived of oxygen. And as, and so the individual wakes up and, and, and splutters and, and snores and all the rest of it. And now that's serious. And, and, and that needs to be looked at by a GP. And there are easy ways to f- to fix it. Um, so do you know, just make sure that your, your partner doesn't have obstructive sleep apnea.

    2. RC

      So when you're, um, giving us that warning, are you essentially saying, "Let's look after our partner"? If you think there's an issue before you move into the spare room-

    3. RF

      Yeah

    4. RC

      ... just have a look and, and at least ask the question, could this be sleep apnea? Is that what you're getting at?

    5. RF

      Exactly, yes. And of course, you can get apps which you can download a- and actually listen to your snoring pattern. And people have done that. Um, and they're pretty accurate too. So yes, just be careful that it's not obstructive sleep apnea. Um, snoring is, is one issue, and of course, snoring can be enhanced by increased weight gain. Rather sadly, as we get older, um, we deposit more fat in the tongue.

    6. RC

      Mm.

    7. RF

      And so, so, so that can also restrict the airway. Alcohol, of course, will relax the musculature, and you're much more prone to snore, uh, if you've had, um, too much alcohol.

    8. RC

      Yeah, it's interesting. I spoke to the US physician, Dr. William Lee, last year on this podcast, and he's done a lot of research into food, but also visceral fats.

    9. RF

      Mm-hmm.

    10. RC

      And he said one of the first places we store visceral fat in the body is in the tongue.

    11. RF

      I know. Isn't it extraordinary?

    12. RC

      Yeah.

    13. RF

      Who'd have thought it? Yeah.

    14. RC

      Mm. So-

    15. RF

      Isn't it... It's bad enough getting old without having a fat tongue. [laughs]

    16. RC

      You mentioned snoring, and you mentioned obstructive sleep apnea.

    17. RF

      Yeah.

    18. RC

      Just so we're bringing everyone along, uh, and no one's getting confused, they're different things, aren't they?

    19. RF

      Yeah. They, they, they-

    20. RC

      But they can be overlapped.

    21. RF

      Yeah, exactly, yes. So snoring would be just the vibration of, of, of, of, of the tissues in the back of the throat. Um-

    22. RC

      Anything to be worried about snoring?

    23. RF

      Um, I don't know. I mean, if it's very loud, um, I, I'd sort of think about some corrective measures, such as making sure that you're not drinking too much, that, um, you may want to sort of prop yourself up a, up a bit. But broadly speaking, straight snoring is noth- nothing to be particularly worried about. But obstructive sleep apnea is, 'cause what you're doing is you're having periods of oxygen deprivation to the brain, and then when the brain wakes itself up, it... you're getting surges in blood pressure, and that can be very bad for the small vasculature in the eye, for example, um, and of course, in the brain. So, so that really does need to be looked at. And, and so there are, there's a, a correlation between, uh, higher rates of s- of obstructive sleep apnea and dementia, for example.

  3. 6:20 – 7:15

    Getting evaluated: sleep clinics, GP routes, and monitoring apps

    1. RC

      If someone is listening to this and they do snore-

    2. RF

      Mm-hmm

    3. RC

      ... or their partner snores-

    4. RF

      Yeah

    5. RC

      ... and they're not sure, is this just a bit of mild snoring-

    6. RF

      Mm

    7. RC

      ... or is this something more serious?

    8. RF

      Mm.

    9. RC

      What would you advise them to do?

    10. RF

      Well, ideally, you go to your GP and they'll recommend you go to a clinic, and where, where you'll spend a, a, a night, and then they, they'll, they'll look at you in some detail. And, and they'll monitor the, the breathing and, and, and the snoring and the potentially the obstructive sleep apnea. But there are so few sleep clinics like that, it's tricky. Uh, and I mentioned that there are apps you can download. And so what I, I, I would recommend is talking to the GP, seeing what the options are, and if, if there's a waiting list of two years or whatever it is to get to the sleep clinic, ask specifically about what NHS recommends in terms of downloadable apps to monitor your snoring and potential sleep apnea.

  4. 7:15 – 11:22

    Why Foster distrusts sleep trackers (and what might change with AI)

    1. RC

      Now, in our first conversation, Russell, I asked you what your views on sleep trackers were.

    2. RF

      Hmm.

    3. RC

      And you were quite clear that there's very few uses you thought they were good for.

    4. RF

      Yeah.

    5. RC

      You were sort of saying that, sure, for some people they might be okay, but you were saying that no sleep federation actually endorses the use of them.

    6. RF

      Yeah, that's still the case.

    7. RC

      So that's still the case?

    8. RF

      Still the case, yeah. And so, so, so none of... And then, and, and also none are FDA approved at the moment.

    9. RC

      Which means what? For, for an individual who's thinking-

    10. RF

      Hmm

    11. RC

      ... "You know what? I see all these adverts-

    12. RF

      Yeah

    13. RC

      ... for sleep trackers, maybe a ring or maybe a bracelet-

    14. RF

      Yeah

    15. RC

      ... that I wear 24/7," why should they be concerned or why should they proceed with caution over the fact that you've just said they're not approved by the sleep federations?

    16. RF

      Yeah. Well, well, well, so for example, you'll often read, um, medically validated, and that can mean just about anything. Um, uh, uh, and so for example, what it often means, and excuse me for being cynical, is that it's been tested on eight, um, Californian undergraduates, um, for a couple of nights in a sleep lab, uh, if you're lucky. Sometimes it's only one night in a sleep lab, and that's just not good enough. Um, and also because sleep is so dynamic, as we discussed last time, a single, um, um, um, algorithm, uh, is simply not gonna work across the variety of sleep patterns that we see and as sleep changes as we age. Now, I'm down on them now, um, and as I said before, they can be useful in terms of telling you roughly what time you went to sleep and what time you woke up, and that's can be... and if you woke up in, in the middle of the night. But anything more sophisticated than that, I would be very uneasy about. And indeed, there are now instances of people using these, these devices and, and, and getting sleep anxiety. It's now a recognized condition.

    17. RC

      Yeah.

    18. RF

      People get so worried about the sleep information they're getting from these apps, and they're, they're, in large measure, i- inaccurate. Um, so don't take them too seriously. However, what I think is on the horizon with AI is a much more interactive device, which means that it can pick up biometric signals, accurate biometric signals.

    19. RC

      A- and what does that mean?

    20. RF

      Well, it can tell, you know, roughly what your, your breathing rate is, your, your pulse rate, um, and, uh, your activity accurately, and integrate that into a dynamic algorithm which can say, "Ah, yeah, I understand. I can tweak the algorithm that fits this sort of person's sleep habits." And so, uh, I think that they might, as time goes on, I would imagine in 10 years' time, they will be more useful, and they probably give a much greater accuracy for the sleep that we, that we actually experience.

    21. RC

      Yeah, I guess so. Like many things, it's early technology.

    22. RF

      Yeah.

    23. RC

      It's rapidly evolving.

    24. RF

      Yeah.

    25. RC

      And maybe in the future they'll be a lot more accurate. What's really interesting, I don't think I shared this with you last time we spoke. In fact, I don't think I'd had the conversation at that point. Just over a year ago, I spoke to the Kenyan elite marathon runner, Eliud Kipchoge. He's the only marathon runner to have run under two hours, a marathon in under two hours, which is just-

    26. RF

      Yeah

    27. RC

      ... staggering, basically.

    28. RF

      It's absolutely extraordinary.

    29. RC

      And he does wear, uh, an Oura Ring-

    30. RF

      Hmm

  5. 11:22 – 14:41

    How to tell if you’re sleeping enough: simple self-checks and the weekend trap

    1. RC

      So what are the best questions that one can ask themselves to determine if their sleep is adequate-

    2. RF

      Yeah

    3. RC

      ... or they're sleeping enough?

    4. RF

      Oh, and that's straightforward, you know. Um, uh, it, it... I, I suppose the first would be, do you feel that you can function optimally during the day? Are you, are you firing on all cylinders? Uh, do you, um, rely on an alarm clock to wake you up in the morning, uh, or a partner to, to wake you up in the morning if you're staying in the same bed? Um, uh, do, do, do you feel tired and sleepy during the day? Critically, do you oversleep on free days at the weekend, for example?

    5. RC

      And what does that mean?

    6. RF

      Well, basically, um, normally, you know, you've got, you've got to get up at a particular time during, during the, the, the, the week, and then you're, you're sleeping in for two or three hours, uh, at the weekend, and that's telling you you're not getting enough sleep, uh, during the week, and so you need to go to bed earlier and get the sleep that you need. Um, and it's worth bearing in mind that many people think, "Oh, I can just completely catch up, um, by oversleeping at the weekend." You can partially, but not fully. Some really interesting experiments have shown is you don't fully catch up after a, a, a weekend of, of oversleeping. You're still starting Monday with a sleep debt. So you've got to really get that stability. The other problem, of course, about oversleeping is that you're not getting the morning light, which is so important for setting the body clock and the sleep-wake cycle.

    7. RC

      To make it really practical though, Russell, some people will say I get what you're saying, but my life is tough in the week-

    8. RF

      Yeah

    9. RC

      ... with my children, with my work demands. I just can't go to bed at a time that would be optimal, and I do need an alarm clock because my job-

    10. RF

      Yeah

    11. RC

      ... is what feeds me and my family.

    12. RF

      Mm.

    13. RC

      In that situation, at the weekend, let's say on a conventional, uh, Monday to Friday job, is there a downside to sleeping in? And the second part to this question is what about catch-up naps on a Saturday afternoon or a Sunday afternoon?

    14. RF

      Yeah. Okay. Um, so yes, it is, it is difficult, but it's all about prioritizing. Um, because we can cut our sleep, we think that we can squeeze other sorts of activities into the time that we would normally sleep. So we've got to take our sleep seriously, and if we need eight hours or seven hours, we need to go to bed at a time that will deliver that duration of sleep that we need. So it's, it is about prioritizing. Um, oversleeping, as we touched on, uh, is you won't catch up fully, and you can delude yourself that you can, "Oh, I can oversleep at the weekends. I'll be fine for Monday." The data suggests that that is not the case. You can certainly... It can certainly reduce the sleep debt but not fully. The other key thing, of course, is you're not getting that morning light. You're not getting that, um, that, that important time giver to set the clock and the sleep-wake cycle accordingly. So, uh, you know, all of the, the data that we've got suggests that it's regularity which is the key thing that we have to achieve for our sleep-wake cycle.

    15. RC

      You mentioned morning light. I know we covered it in our first conversation-

    16. RF

      Mm

    17. RC

      ... but for anyone who's not heard that, perhaps give us an overview, you know.

    18. RF

      Yeah.

    19. RC

      What is morning light? Why is it so important, and how much do we need?

  6. 14:41 – 20:33

    Morning light and the master clock: why timing matters

    1. RF

      Yeah. So we have this internal clock, which is fine-tuning our biology to the very demands of the 24-hour day. Um-

    2. RC

      And what is it? You say internal clock. Many of us picture a clock on our desk, right?

    3. RF

      [laughs]

    4. RC

      So, so, you know-

    5. RF

      Yeah

    6. RC

      ... when, when you say we have an internal clock, what, what does that look like?

    7. RF

      Well, actually there is a master clock within the brain. Um, uh, and it's called the suprachiasmatic nuclei. So essentially you can think about where this is. As the optic nerves go into the brain and fuse, sitting above there is a small paired structure of about 50,000 cells, and, and, and each one of those cells is capable of generating an endogenous 24-hour rhythm. I mean, it's just extraordinary, and it's based upon a molecular feedback loop. So clock genes are turned on. They make their proteins. Those proteins then form a complex. They then go into the nucleus and turn off their own genes. The protein complex is then degraded-

    8. RC

      Wow

    9. RF

      ... and then the whole thing can start again. And so it's a, it's a biological oscillation of about 24 hours, but it's not exactly 24 hours. Um, and so it needs to be set to the, to the real day, so the internal day needs to be aligned to the external day. And the most important thing for that, it's not the only thing, but the most important thing is light. Now, light does different things to the clock at different times. So morning light makes us get up earlier. It advances the clock. Evening light delays the clock, makes us get up later. Now, because most of us, 90% of us, have a body clock that is slightly longer than 24 hours, we under constant conditions would drift later and later and later. So what we need to be entrained to get that internal clock aligned to the external world is a daily nudge, an advance. That's why morning light is so important, 'cause it gives us that advance, um, uh, which is what we need on a daily basis. So interestingly, um, we did some studies on some students all over the world. Um, and of course, students are notoriously late types. But we found that the later the chronotype, and I know we touched on chronotypes last time, the more evening light they got, which would delay the clock, at the expense of morning light. So they were sleeping through, not getting the advancing morning light, but they're out in the late afternoon, early evening, getting the dusk light, which is delaying the clock even further. So when we see light, it's so important.

    10. RC

      So we wanna get light exposure, ideally natural light outside-

    11. RF

      Yes

    12. RC

      ... as close to our wake-up time as possible.

    13. RF

      Yeah, exactly. Yeah.

    14. RC

      Now, couple of things to elaborate on there. We're recording this conversation in January-

    15. RF

      Mm-hmm

    16. RC

      ... in the UK.

    17. RF

      Yeah.

    18. RC

      So we're at the height of the British winter-

    19. RF

      Yeah

    20. RC

      ... which means it doesn't often... Depends whether it's, uh, clouds in the sky or clear.

    21. RF

      Mm.

    22. RC

      But it can often be 8:00 AM until you're getting morning light.

    23. RF

      Absolutely, yeah.

    24. RC

      So-

    25. RF

      Well, it was. It is. It is at the moment, about 8:00 AM. Yeah.

    26. RC

      So many children, uh, many adults are having to get up, let's say, at 6:30 AM to get ready for their day's activities.

    27. RF

      Yeah.

    28. RC

      So they get up at 6:30, let's say, with an alarm clock, which may not be ideal, but may be in reality what's happening for a lot of people. Your advice is you need to get morning light as soon as possible.

    29. RF

      Yep.

    30. RC

      Now, morning light may not be available from the outside until 90 minutes after that.

  7. 20:33 – 25:52

    Light as a drug—and modern ‘junk light’ culture

    1. RC

      This is a really interesting point, something I wanted to discuss with you today. This idea that light is medicine, this idea that light is a drug.

    2. RF

      Hmm.

    3. RC

      But we as a society don't see light as a drug. We, we just think what we can expose ourselves to whatever light we want, whenever we want, you know. Light is, you know, separate to our lives. We get on with our lives. We do our work. We go on social media. We see our friends. We do whatever, but we don't give attention to light.

    4. RF

      Hmm.

    5. RC

      But your trial that you just mentioned there, or certainly the trial you're, you're citing, is really comparing light to a drug.

    6. RF

      Yes, yes.

    7. RC

      Right?

    8. RF

      Absolutely, yeah.

    9. RC

      So in your view, is... Should we consider light as powerful as drugs?

    10. RF

      I think we absolutely can. I'm, I, I'm, and it, and it would be naive not to think that, uh, for the following reason. You know, all life on Earth has evolved on a planet that rotates once every 24 hours. We're exposed to a light-dark cycle. The light-dark cycle has dominated our evolution and our biology. Um, and because from, what, the 1950s we could produce cheap, affordable, efficient light, we've invaded the night, um, and we've thrown away this incredible part of our biology, uh, as a result. And, and it's, and it's fascinating that, that, that, you know, the, the humans are wonderful. I mean, we're remarkably arrogant. We, we think we can do whatever we want, whatever time we choose. I mean, you know, it's part of the success story. Uh, uh, but actually, w- we do it at some considerable cost, and I think, I think it's about tuning in to those incredibly powerful biological drivers, environmental drivers of our biology.

    11. RC

      You say it's part of our success story, and again, this is something I've been reflecting on recently on, on long walks, Russell.

    12. RF

      [laughs]

    13. RC

      This idea that we say that humans are really evolved, and look at what we've achieved with our skyscrapers and our phones and our technology. But you could also make the case that we have epidemic rates of chronic disease. We have epidemic rates of mental health dysfunction.

    14. RF

      Hmm.

    15. RC

      And so I guess sometimes we need to challenge the narrative that this is a success story. Do you know what I mean?

    16. RF

      I, I, yeah.

    17. RC

      I know that's slightly controversial, and I, I'm not pushing back at what you're saying. I just think as a general point, it's, like, worth considering that there are some cultures and some parts in the world where, yes, let's say they've got other issues to contend with.

    18. RF

      Hmm.

    19. RC

      But their chronic disease rates are much lower. They don't have mental health dysfunction. Like a lot of hunter-gatherer tribes, yes, they may have threats from predators. And we regard our lives as better, many of us, which speaks to this arrogance that I think many-

    20. RF

      Yeah

    21. RC

      ... modern humans have. But I think we could also make a case to go, "Well, is it necessarily better?" [laughs]

    22. RF

      Well, I'm, I'm certainly arguing for a bit more humility. It's all about, it's understanding.

    23. RC

      Yeah.

    24. RF

      And of course what we haven't had is, uh, uh, out there, the education that allows us to make sensible decisions-

    25. RC

      Yeah

    26. RF

      ... about our lives, and, and that's the thing that's changing. And I think people are thinking, "Hang on. I, I do need to reconnect a bit. I do need to get that, that balance-

    27. RC

      Yeah

    28. RF

      ... i- i- into balance." Um, and, and so I th- uh, yeah, I, I... It's all about education for me, and it's, it's trying to have the information to make the best decisions about our lives.

    29. RC

      Yeah.

    30. RF

      Um, and so that we can embrace the extraordinary successes of our species-

  8. 25:52 – 31:06

    Couples’ sleep solutions: duvets, earplugs, and temperature mismatch

    1. RC

      Let's just go back to partners for a minute sleeping in separate beds. When you have spoken about this at live talks or in the-

    2. RF

      Mm

    3. RC

      ... media before, you know, what kind of comments have you had from people? Has there been a lot of pushback? Are some people saying, "No, my husband and I have been doing this for 30 years, and it's the best thing we ever did"? Or are you mostly getting pushback against that idea?

    4. RF

      I'm not getting pushback. In fact, what's happened is that a bunch of celebrities, you know, then came out saying, "Oh, yeah, well, of course, we sleep in separate beds." And, and, and, and, and actually, of course, endorsement by a celebrity means it's kind of okay to many people. [laughs]

    5. RC

      We're getting endorsement by you-

    6. RF

      Yeah, yeah. I mean, we-

    7. RC

      ... because we're studying this

    8. RF

      ... yeah. Um, and so, uh, I know, I, I, it's been the reverse. People... I think actually people have felt, "Phew, I'm so relieved. I don't have to feel guilty about it any longer."

    9. RC

      And I think initially people probably push back because they think, "Yeah, but what about intimacy?"

    10. RF

      Mm.

    11. RC

      But I don't think sleeping in the same bedroom equals intimacy.

    12. RF

      No.

    13. RC

      Because you could, let's say, I mean, it's not an extreme example at all. I think it's happening in many bedrooms around the world [laughs] where you're in a double bed with your partner, and each of you are on your own devices.

    14. RF

      Mm.

    15. RC

      Right? You're physically in the same space, but mentally you could be tens of thousand miles away. One of you is in your curated world-

    16. RF

      [laughs]

    17. RC

      ... of entertainment. The other one is in their curated world. So yeah, sure, you're in the same bed.

    18. RF

      Yeah.

    19. RC

      But is that intimacy?

    20. RF

      No.

    21. RC

      Well, no.

    22. RF

      No. No, absolutely. And of course, you know, if you want to promote intimacy, you have to have empathy. You have to be responsive to the, the, the, the behavior of your partner. You have to have a sense of humor [laughs] often. You have to, you have to enjoy other people, and you'll enjoy other people a lot more if you've had a good night of sleep.

    23. RC

      So one option is separate rooms.

    24. RF

      Yeah.

    25. RC

      The other option which you have touched on, which you first came across in Germany-

    26. RF

      Mm

    27. RC

      ... is you're still in the same bed, but you have a separate duvet.

    28. RF

      Yeah.

    29. RC

      Are there any other options you can think of when it comes to couples potentially sort of dealing with th- this issue?

    30. RF

      Yeah. I mean, of course, the, the default is, is, um, um, uh, ear, earplugs. Um, but a lot of people just can't cope with those, um, uh, to, to block out any snoring noise, for example. Um, but temperature, I think, is also an important factor.

  9. 31:06 – 37:58

    Biphasic sleep, historical patterns, and seasonal changes in sleep need

    1. RC

      At the end of our first conversation, Russell, you briefly touched on biphasic and polyphasic sleep.

    2. RF

      Right. Yeah.

    3. RC

      I wonder if we could retouch on that. But then linked to that, I'm wondering, you know, has any of your work studied tribes? You know, hunter-gatherer tribes or, you know, tribes in different parts of the world. How do they sleep? If there is a couple there, for example, a man and a woman, do they sleep in the same bed, or are they in, in different places?

    4. RF

      Yeah. Okay, we need to go back to a wonderful chap called Rog- Roger Ekirch, um, and he looked at the sleep habits of pre-industrial Europeans, um, uh, from the writings, the diaries, um, and, and kept on finding references to a first and a second sleep. Um, and, and so went through, and, and there were records that go way, way back to a, a polyphasic sleep. So not sleep in a single consolidated eight hours as we're all told we've gotta have, but people would wake up, they'd interact, um, then they'd go back to sleep again. And this was common. This was just the norm. And then it seems that, uh, as we've developed a more industrial society, and we've compressed our opportunity to sleep, the polyphasic sleep pattern is not as clearly pronounced as it was. You know, the, in the pre-industrial societies, light was incredibly expensive. I mean, a, the cost of a candle in the 19th century was almost equivalent to a working man's daily wage.

    5. RC

      Wow.

    6. RF

      You couldn't afford... And also, they were made of fat, and you couldn't afford to burn fat because, you know, you, most people were, were food poor. And so you-

    7. RC

      Wow. That's so interesting

    8. RF

      ... you, so we would, s- so the sleep-wake cy- cycle was, was dictated to a large extent by the, the, the, the natural light environment. So anyway, um, Roger's work then stimulated a chap called Tom Wehr to do some experiments and, and he got young people into the lab, exposed them to 12 hours of light, 12 hours of darkness. So, you know, expanded the nighttime opportunities to sleep, and what he found was they became biphasic. So they then, then sort of would go to sleep, they'd be asleep for a few hours, wake up, and then they'd go back to sleep again. Uh, and, and so you see this also in societies now without electric light. So people have studied Till Roenneberg, for example, societies in South America, and shown very nicely that sleep isn't a single consolidated block, and that's so important because we know we're told eight hours consolidated. This is the perfect sleep pattern. And when people wake up, they think, "Oh my God, never gonna get back to sleep. Um, I may as well start doing emails and drinking coffee." And, and of course, if you know that the biology, uh, is, is, is like it is, and so if you stay calm, you stay relaxed, you keep the lights low, your chances are you will go back to sleep.

    9. RC

      So potentially we could make the case that a biphasic sleep pattern is the kind of natural human way to sleep.

    10. RF

      Yeah.

    11. RC

      Can we say that?

    12. RF

      Well, I think, I think that's fair, uh, under those sorts of circum- circumstances. So for example, you would expect that biphasic, polyphasic sleep would be the dominant sleep type during the long nights of winter. I think perhaps by the time we get to the short nights-

    13. RC

      Mm

    14. RF

      ... um, in the summer, we might find that the sleep patterns would, will, will change. So I think it'll depend upon changing, you know, light-dark signals. But yeah, I, it's perfectly normal to have biphasic or polyphasic sleep at certain times of the year, I would say.

    15. RC

      And on that, something I've often felt, which kind of speaks to your work really, Russell, is that society has really lost its relationship with rhythm.

    16. RF

      Mm.

    17. RC

      You know, everything in nature, in life operates with rhythms.

    18. RF

      Absolutely. Absolutely. Whether it be a heartbeat, whether it be-

    19. RC

      Yeah

    20. RF

      ... electrical activity, um, whether it be the sleep-wake cycle.

    21. RC

      And even if we think about, let's say, a seven-day rhythm, and we think about the fact that certainly when I was a kid, supermarkets in the UK were closed on Sundays.

    22. RF

      Oh, yes.

    23. RC

      Now, what's really interesting, if we really reflect on that, and of course, many religions have a Sabbath or, or some sort of day of rest ingrained within them.

    24. RF

      Mm.

    25. RC

      Pre-internet, pre-supermarkets being open seven days a week and having online shopping seven days a week, you would naturally have rest on a seventh day.

    26. RF

      Yeah.

    27. RC

      Right? So we have a rhythm there, and I, I kind of feel modern society tries to make us feel that every day is the same. Now, I get that we want similar wake-up times and bedtimes to help us with our circadian rhythm. But you mentioned winter and summer, and for many years it's felt quite natural to me that in the winter, let's say in a Northern Hemisphere country like the UK, where you do have short days in the winter-

    28. RF

      Mm-hmm

    29. RC

      ... and, you know, it's not light till 8:00 AM, it's, it's dark at 4:30 PM, and it's even more pronounced of that in places like Scandinavia. It kind of makes sense that you would spend longer in bed-

    30. RF

      Mm

  10. 37:58 – 41:33

    Temperature, baths, and the biology of falling asleep

    1. RC

      Temperature.

    2. RF

      Right.

    3. RC

      What's the relationship between temperature and sleep?

    4. RF

      Yeah, it's really interesting. So if we, if we go-- if we start with the circadian changes in temperature, uh, so, so we're told that temperature is about thirty-seven degrees C. Um, but actually, if we go to the early morning, uh, two, four o'clock in the morning, it's at its lowest point, and it might be as, as much as one degree below thirty-seven degrees.

    5. RC

      So this is our body temperature.

    6. RF

      Our core body temperature, yeah. And then in anticipation of increased metabolic rate, uh, increased activity, our temperature is driven by the clock to start rising. And it rises and rises throughout the day. And then about six, seven o'clock in the evening, it begins to decline to that low point in the early hours of the morning. Now, what's critical is that that circadian-driven rhythm in temperature also impacts upon the sleep-wake cycle, because that evening drop in core body temperature, uh, seems to be a signal to initiate sleep. So part of the physiology of going to sleep involves a drop in core body temperature, and if you block that drop in core body temperature, it's much more difficult to go to sleep. So it's a really important part of our biology.

    7. RC

      And this, of course, is why hot showers and hot baths can be helpful before bed.

    8. RF

      Yeah. I know. This-- it's ironic, isn't it?

    9. RC

      Yeah.

    10. RF

      You think you've gotta, you've gotta promote cooling, but you're doing it with a, with a hot bath, uh, or warm bath. Um, and the reason, of course, is that what the warming of the bathwater does is to vasodilate, to expand the blood vessels in the hands and the arms and the legs and the feet, which means that blood is being shunted from the core, where it's hot, to the periphery, and that h- that, that heat is being lost to the outside. So that's why a, a warm bath can actually, um, promote going to sleep. Relaxing, of course, but also it's, it's producing that, that s- helping produce that, that subtle drop in core body temperature.

    11. RC

      And again, that makes sense if we think about our evolution. Um, you know, we were living on the equator, and presumably in the day it would be hot, and presumably at night the sun would go in, it would be dropping temperature, right?

    12. RF

      Yeah.

    13. RC

      So we've evolved under those conditions.

    14. RF

      Yeah.

    15. RC

      And so I guess these modern temperature-controlled houses, again, I can speak about Britain 'cause that's where I live, in the winter with heating on-

    16. RF

      Mm

    17. RC

      ... I think a lot of people don't realize that having the heating on in the bedroom, there's a balance of course-

    18. RF

      Yeah

    19. RC

      ... but you can make it too hot.

    20. RF

      Oh, absolutely, yes. Um, and, and there's some discussion about what's the optimum temperature for a bedroom. I suppose the consensus is about eighteen degrees. Personally, I like it much cooler. I turn the heating off, um, and sometimes even open the window, so I like it nice and cool. Um, uh, but a recent study sh-showed that in elderly people, sixty-five, seventy and older, that the optimum temperature for sleep was closer to twenty-two degrees. So-

    21. RC

      That's quite a big change.

    22. RF

      It's a big change, yes. And I have to say, the data surprised me. Uh, s-so, you know, everybody's different. You'll have to find, you know, what works for you. But of course, it's not simply the, the, the temperature in the room. It's the sort of bedding you're using, and of course, whether it's an effective duvet with layers which are keeping, keeping you warm, or it's something much lighter, and therefore you're gonna lose heat. A-and, and certainly if it's too cold, you're more likely to wake up. Uh, so, so yeah, y-you've gotta get the balance right, again, with, as with everything. Uh, but yes, but ideally a slightly cooler bedroom temperature would be, um, the best for promoting sleep.

  11. 41:33 – 54:18

    Lux, indoor darkness, and why daylight protects against evening light

    1. RC

      You mentioned lux before-

    2. RF

      Mm

    3. RC

      ... which of course is a unit of light. Could you expand on lux?

    4. RF

      Yeah.

    5. RC

      You know, what, what exactly is it? And maybe give us some examples of the amount of lux we're often exposed to-

    6. RF

      Yeah

    7. RC

      ... when we're either inside or outside.

    8. RF

      Yeah. So lux is a, an old measure of, of environmental brightness, and it's essentially calibrated to give you a sense of brightness as it would appear to a human observer. So the, the, the, the, the response of the detector is not flat, meaning that it doesn't absorb all wavelengths equally.

    9. RC

      Mm-hmm.

    10. RF

      It actually has a bell-shaped response, which peaks in the sort of greeny, greeny part of the spectrum at five five five nanometers, um, which is, which is where humans are, are maximally sensitive to their daylight vision. Um, so, uh, lux comes in values. So if we think about, um, the sort of a, a light that we'd see outside, uh, so shortly after dawn on a clear day, you would have about ten thousand lux. By noon, that could get to a hundred thousand lux, even in Britain. Now, you know, it's not-

    11. RC

      And is it-

    12. RF

      Go on

    13. RC

      ... uh, do we just measure it as a static measurement, or is it more if you are outside on a sunny day in July in the UK for ten minutes, you get X amount of lux.

    14. RF

      Yeah.

    15. RC

      If you're there for twenty minutes, you get Y amount of lux. Is it like that?

    16. RF

      Yeah, yeah, you, you, you... It's, it's certainly additive. And, and of course, it's constantly fluctuating because of cloud cover a-a-and, and whether you're moving inside or under a tree or whatever. So, but if you just took your lux meter out, and you pointed it skyward, you could get up to a hundred thousand lux on a bright, bright, sunny day. Most of the time, it's gonna be something around fifty, sixty thousand lux. But as we go inside, this is where the big changes are occurring. So if you stand, uh, on a reasonable sunny day, uh, and you point the, the, the meter at the window, you could get between three thousand lux and, and a thousand lux. Walk two to three meters into the middle of the room, and it's dropped to maybe as little as, as, as a hundred lux.

    17. RC

      And why is that a problem?

    18. RF

      Well-

    19. RC

      Or a potential problem?

    20. RF

      Well, yeah. Uh, uh, and of course, the sorts of levels of light you're seeing in the evening would be something like ninety lux, um, in, in most domestic settings.

    21. RC

      Even with bright kitchen-

    22. RF

      Well-

    23. RC

      ... LED lights on?

    24. RF

      It, it varies of, of course, a lot. And, and kitchens now are, are very well illuminated, so that would be more. That would be four, five hundred, maybe even six hundred lux.

    25. RC

      Mm.

    26. RF

      So the sort of light you get from a Kindle, for example, on maximum setting would be thirty lux.

    27. RC

      So very low.

    28. RF

      So low, yeah. Uh, and, and so what does it all mean? Well, the circadian system requires relatively bright light over a, an extended period of time. And so there's a lot of controversy at the moment because sort of people have said, "Okay, well in fact domestic light setting, let's say a hundred lux, will actually shift the clock." But you have to have seven and a half hours of light exposure to get any effects. So it's a good example of where intensity and duration are being titrated and integrated by the circadian system. However, other s- more recent studies have shown that actually those low levels of light, even for seven hours or so, are completely abolished if you've seen relatively bright light during the day. So we said that dawn and dusk are, is sort of the most important times for shifting the clock, but the clock is, the clock sensitivity is being gated by the sort of light exposure that you get during the day. So what these, these studies showed is that five hundred lux or more during the day for four or five hours would actually abolish even subtle effects of dim light in the evening, which I think is really interesting.

    29. RC

      Okay. Let me just try and summarize that to check I've got it right. So you're initially saying that the, essentially the, the lux you will expose your eye to outside dramatically outweighs anything you could get inside.

    30. RF

      Broadly speaking, yeah.

  12. 54:18 – 1:15:49

    Light, psychiatric risk signals, and the school-screen dilemma for children

    1. RC

      So I wanna come on to nighttime exposure in the evening. I'm very passionate about what's going on in schools at the moment. We'll get to that. But perhaps a way of getting into this part of the conversation is this paper that was published in October 2023 in Nature.

    2. RF

      Mm-hmm.

    3. RC

      It's called Day and Night Light Exposure Are Associated With Psychiatric Disorders: An Objective Light Study in Greater Than 85,000 People.

    4. RF

      Mm.

    5. RC

      Now, can I just read a couple of lines from the abstract?

    6. RF

      Hmm.

    7. RC

      "Greater nighttime light exposure was associated with increased risk for major depressive disorder, generalized anxiety disorder, PTSD, psychosis, bipolar disorder, and self-harm behavior." Okay, so greater nighttime light exposure is associated with all of those things.

    8. RF

      Hmm.

    9. RC

      And then it says, "Independent of nighttime light exposure, greater daytime light exposure was associated with reduced risk for major depressive disorder, PTSD, psychosis, and self-harm behavior," which speaks to some of the things-

    10. RF

      Yeah

    11. RC

      ... you've, you've just been mentioning. And one of the conclusion lines was- Avoiding light at night and seeking light during the day may be a simple and effective non-pharmacological means of broadly improving mental health.

    12. RF

      Yeah.

    13. RC

      Now, that's really, really interesting.

    14. RF

      Mm-hmm.

    15. RC

      You know this, uh, paper very well. Perhaps you could comment on some of your thoughts about it.

    16. RF

      Yeah, I, I mean, over a decade ago, w- we were, we're talking about the influence of sleep and circadian rhythm disruption on, uh, mental health and mental illness. And, and, you know, we showed that, um, uh, led by Dan Freeman, a, a psychiatrist i, i- in, in Oxford, that if you could even partially stabilize the sleep-wake profile of individuals with insomnia and showing paranoia and hallucinatory experiences, s- partial stabilization of the sleep-wake profile using cognitive behavioral therapy, which of course is going to bed and getting up at the same time, eating at the same time, and of course, that involves light exposure, um, would reduce paranoia and hallucinatory experiences. And so what this paper has gone on, I think, really very elegantly to show is that, yeah, a stable, robust light-dark cycle im- almost certainly improves circadian health and therefore sleep health and therefore mental health. So it's all part of the same package. Uh, and, and I, and it's great. And, and I think this is, this is another really important way of showing that the sleep-wake cycle is a therapeutic target for mental illness. We should just, you know, use it-

    17. RC

      Yeah

    18. RF

      ... uh, much more effectively than we are at the moment.

    19. RC

      Now, Russell, on a personal level, in my capacity as a medical doctor, I have seen at least twice, actually more, but two very clear cases, one I've spoken about before on this podcast, one I haven't, where adolescents-

    20. RF

      Hmm

    21. RC

      ... who were suicidal-

    22. RF

      Hmm

    23. RC

      ... significantly improved their wellbeing, and I, I mean significantly, by reducing light exposure in the evening.

    24. RF

      Mm-hmm.

    25. RC

      Right? One of them in particular, it was two hours before bed.

    26. RF

      Yeah.

    27. RC

      I said, "Look, let's really try. Get off everything."

    28. RF

      Yes.

    29. RC

      Phone off, laptop off. The difference in mental wellbeing was marked.

    30. RF

      Yes. Yes. And, and studies have, have been, you know, would support that.

  13. 1:15:49 – 1:36:31

    Sleep aids and myths: pills, magnesium, melatonin, nightlights, and ‘light behind the knee’

    1. RC

      Let's move on to sleep aids.

    2. RF

      Hmm.

    3. RC

      Okay? So let's talk about sleeping pills. Let's talk about magnesium. Let's talk about melatonin.

    4. RF

      Yeah.

    5. RC

      These are things that people commonly use either by themselves or they're prescribed by their doctor. What's your take on them?

    6. RF

      If we look at the biology, first of all, then these sleep aids, largely speaking, um, hit the GABA system, so GABA, amino butyric acid. It's a neurotransmitter which acts to inhibit the actions of the central nervous system. So we've got all of these excitatory neurotransmitters, which increase alertness, increase the stress axis, and all the rest of it, and what GABA does is turn that down.

    7. RC

      So you mentioned the word neurotransmitter.

    8. RF

      Yeah.

    9. RC

      For anyone who doesn't understand that, can you just put that-

    10. RF

      Yeah

    11. RC

      ... in layman's terms?

    12. RF

      So we have neurons, and they talk to each other via synapses, and chemical synapses involve the release of a neurotransmitter at those junctions, which then stimulate the next neuron down the chain.

    13. RC

      So, so chemicals in the brain-

    14. RF

      Yeah

    15. RC

      ... to send messages between nerve cells.

    16. RF

      Yeah.

    17. RC

      And GABA is one example. Can you give us examples of others?

    18. RF

      So GABA... and GABA's one of the ones which actually reduces that transmission, so it, it calms-

    19. RC

      It calms things down

    20. RF

      ... it calms things down, yeah. And so, for example, the benzodiazepines, Valium, or the Z drugs, um, uh, zopiclone, um, they actually act by promoting, uh, in- increasing the sensitivity of the GABA systems, which means that you're, you're sort of turned down, so you're reducing excitatory neurotransmission release.

    21. RC

      So, okay, so GABA is a calming neurotransmitter. What are examples of neurotransmitters that do the opposite, that excite us?

    22. RF

      Oh, oh, uh, just about everything else. I mean, [laughs] so, so, yeah, the, the, the elements of the, the, of the sympathetic nervous system-

    23. RC

      So adrenaline, cortisol

    24. RF

      ... adrenaline, cortisol, yeah, the... exactly, yes. Um, so they would be, uh, uh, all excitatory.

    25. RC

      Okay.

    26. RF

      And of course, we have those projections from, from the hindbrain called the excitatory arousal system, which is this, this, this whole system that is bathing the, the cortex, that, that bit of the brain for consciousness, in excitatory neurotransmitters.

    27. RC

      Okay. So GABA calms things down.

    28. RF

      Mm-hmm.

    29. RC

      So if we can enhance GABA, we can help to switch things off in the brain, which in theory is gonna help promote sleep.

    30. RF

      So sedation is not the same as sleep. So although the, it's working on a similar pathway, so, so sleep does involve a, a, a, a wind- you know, a, an increase in the, in the GABA systems and a winding down of the excitatory systems, but it's a whole bunch of other stuff as well. And you can think of, um, benzos and, and, and Z drugs as being a hammer hitting the conscious centers of the brain. So you're not providing a biological, a complete biological mimic for sleep, and in fact, some of these drugs can, um, benzos in particular, can actually reduce memory consolidation and the formation of, of, of new ideas in response to, to complex sort of questions.

  14. 1:36:31 – 1:47:40

    Aging, nocturia, and designing environments for circadian support

    1. RC

      Okay. Something that often affects people as they get older, it affects their sleep, is the need to pee at night.

    2. RF

      Oh, yeah. I'm, I'm so often asked about this. Yeah.

    3. RC

      Yeah. So what are your initial thoughts about that?

    4. RF

      Well, there's, there's a couple of things going on here. One is that as we age, the amplitude, the strength, if you like, of the circadian drive becomes diminished. So sleep-wake cycle becomes less robust. It's, it, it's sort of, it's a bit more wobbly, but that's also true for the release of many hormones which are under circadian regulation.

    5. RC

      Can I just pause you there a second, Russell?

    6. RF

      Yeah.

    7. RC

      Do we know that that sleep-wake cycle becomes less robust as we get older because that's how we're programmed or because of what we do? Is it environmental? You know, as we get older-

    8. RF

      Yeah

    9. RC

      ... are we going out less? Are we getting less of those environmental inputs?

    10. RF

      Yes, and it's, it's a very good point because, of course, um, it may well be that because the circadian, uh, response to light diminishes as we age, then light that we could, you know, normally drive th- th- the circadian system, uh, earlier in our lives is not as effective. And, and so if you increase the amount of light, for example, in the nursing home environment, you can increase the, the, the, the, the stability of the sleep-wake. And, and what Als and Winyar showed is that when you do increase your light in a nursing home, you not only improve sleep, but you can improve cognition in those individuals showing mild dementia.

    11. RC

      I think that's a really important point, Russell, and one we should just pause on. Because whether we have parents in nursing homes or they're living by themselves in the house or whatever it might be- Paying attention to light exposure in the day, even if they're not going outside, you're basically saying, "Put the lights on, get it really bright in the day. That's gonna help-

    12. RF

      Yeah

    13. RC

      ... sleep and cognition."

    14. RF

      Yes, absolutely. Well, what's interesting is that, uh, architects are getting this. That it's really... They're, they're responding beautifully.

    15. RC

      Oh.

    16. RF

      So the people designing modern nursing homes, and, and buildings generally, are not relying on artificial light to light, but is actually, as much as possible, letting natural light in.

    17. RC

      Yeah.

    18. RF

      And, and in fact, there's now a... There's an award called the Daylight Award for architects who've actually shown that in their building design they've enhanced, uh, the exposure to natural light. Um-

    19. RC

      I love that.

    20. RF

      It's brilliant. It's fantastic, and I'm, I'm on, I'm on actually the, the jury to select these prizes, and, uh, and, and so it's... I've learnt so much about what architects are doing, and the... and how they value light. In fact, there's a, there's an architect called Ian Ritchie, and he says, "The first principle of ar- architecture is natural light." Isn't that brilliant? Hmm.

    21. RC

      I love that. You can almost retire now, go, "My work is done."

    22. RF

      [laughs]

    23. RC

      Right? That, that's wonderful, isn't it?

    24. RF

      Yeah.

    25. RC

      Because that actually is such a serious and such an important point. If more and more buildings, work buildings, home buildings, blocks of flats, nursing homes, hospitals, whatever it might be, were designed with natural light at the heart of them, you're probably immediately gonna have an improvement in physical health, mental health, cognition, all kinds of things-

    26. RF

      Well, yes

    27. RC

      ... without even having to do anything.

    28. RF

      Well, so there's a very interesting set of studies done about 20 years ago-

    29. RC

      To make sure you're taking action after watching this video, I've created a free guide to help you build healthy habits. We can all make short-term change, but can those changes become a fundamental part of our life? Often, they don't, and that's why in this free guide I share with you the six crucial steps you need to take. They're really, really effective. If you wanna get hold of that free guide right now, all you have to do is click the link in the description box below.

    30. RF

      Uh, which looked at different schools, and measured the amount of light the pupils were being exposed to, and then correlated that with grades. Um, and the greater the light, uh, in the classroom, the higher the success in, in terms of grades.

  15. 1:47:40 – 2:04:38

    Rest, naps, mindfulness, weighted blankets, and the risk of sleep anxiety

    1. RC

      I wanna talk about rest for a moment.

    2. RF

      Oh, yes.

    3. RC

      It's something I've, I've been thinking a lot about recently, rest, and one, one of the reasons this has come up for me is that you talk a lot about sleep. I talk a lot about sleep, and what I would notice for quite a few years now is that some people who are apparently sleeping well are waking up feeling unrested.

    4. RF

      Mm.

    5. RC

      And in particular, when I've dived deep here, what I've noticed is a lot of people these days, they are staying stimulated in the one hour before bed.

    6. RF

      Mm. Yeah.

    7. RC

      Whether on a device or anything else, right, they're staying stimulated, so they're not winding down, and they say, "Yeah, I sleep fine, but I wake up feeling exhausted."

    8. RF

      Mm.

    9. RC

      And I found that with those individuals, when I can help them realize the importance of winding down for an hour, ideally 90 minutes, well, let's say an hour, they're actually having the same amount of sleep apparently. They're not measuring it or tracking it, but they're waking up feeling refreshed.

    10. RF

      Mm. Mm.

    11. RC

      I don't know if you have any data to support that or you have any thoughts on that.

    12. RF

      Well, the... Yeah, I, I mean, where we have some interesting data is that during the day, if you could go into a state of quiet restfulness, then you actually do, um, benefit. You, you do feel more restored, and, and your productivity during the second half of the day can improve, and that's without sleep. That's just with quiet, you know, quiet relaxation.

    13. RC

      And it helps you sleep at night?

    14. RF

      And it helps you sleep at night. So, so w- w- there's, it... Napping is a very interesting issue. So the, so the, the, the agreed sort of metric for napping is twenty minutes, ideally no longer than thirty minutes, around the middle of the day can enhance your, your, your ability to function later in the day, and that's going into sleep. Longer than that, it can be c- counterproductive, and of course, the danger for napping is, of course, if it becomes very long because then... and it's close to bedtime, because then it'll push back the pressure for s- uh, sleep, and you, and you'll find it very difficult to get off to sleep. But short naps, fine, and, um, I don't see anything wrong with that on the basis of the, of the data that we know. Um, that quiet relaxation before bed I think is really interesting. We know that, uh, relaxation will allow you to get to sleep ... easier. Whether it produces more restful sleep, and what do we mean by restful sleep? And it's essentially restful sleep is regular sleep. Uh, I don't know. And, and, and, and whether the structure of the REM, non-REM cycle is influenced in some way. And maybe if you're waking from REM sleep naturally, you will feel more rested, 'cause that's how we naturally wake up.

    15. RC

      Mm.

    16. RF

      So if you've used that relaxation, and it's, and it's changed the timing of sleep in some way-

    17. RC

      Mm

    18. RF

      ... so that you then ultimately rake... wake up in REM sleep rather than non-REM sleep, you probably will feel more rested. But we don't have any studies.

    19. RC

      I've seen it in enough people to know there's something going on.

    20. RF

      Yeah.

    21. RC

      Sort of my clinical acumen tells me there's something going on here, and I haven't measured it, but I, I've seen that if you apparently for the same amount of sleep in the same way, if you relax for an hour before that compared to being stimulated, subjectively at least, people are saying, "Oh, I feel much more rested." I felt that myself.

    22. RF

      Yeah. There's some, also some really interesting stuff emerging on using sound frequencies to induce slow wave sleep while you're asleep. And, um-

    23. RC

      EMDR?

    24. RF

      Uh, well, no. It's, it's... Yes. S- so what you've got is these specific, um, uh, frequencies, um, and you can actually, you can increase slow wave sleep. Uh, and that has been... There's one or two papers suggesting that your, uh, memory formation and problem-solving might be enhanced by that, but it's a very tiny effect. Trouble is, it's now, you know, commercial companies are now jumping on it saying, "All right, you can enhance your sleep, you know, with these sound frequencies." And I don't, I don't know how beneficial it will ultimately turn out to be.

    25. RC

      I guess it comes down to what we've repeated on many occasions. If you use sound therapy, and you're waking up feeling better, and you answer those questions, and subjectively you have more energy, your relationships are better, your patience is better, great.

    26. RF

      Yeah. [laughs]

    27. RC

      If it isn't, and it's making you feel more obsessed about measuring all these metrics, it's possibly not.

    28. RF

      Yes, yes. I mean, bottom line is, uh, anything that relaxes you, um, before you go to sleep is gonna be good for sleep.

    29. RC

      Yeah.

    30. RF

      Um, and, and you know, I, I, I was unconvinced by mindfulness when it first started, you know, rumbling around 20 years or so ago. Um-

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