The Science Of The Body Clock: How It Can Revolutionize Your Sleep And Health - Prof Russell Foster

1. 0:00 – 1:33

   Intro

   1. RFRussell Foster0:00

      Circadian rhythms underpin almost every aspect of our health and wellbeing. And that was the bit I wanted to get across within LifeTime, and that we, in a sense, avoid these rhythms at our peril. For biology to function, it, it, it requires the right materials in the right concentration delivered to the right tissues and organs at the right time of day. And it's the circadian system that delivers this extraordinary temporal structure. What are the consequences of ignoring this biology as we do for night shift work, twenty-four/seven society? And it's not all doom and gloom. By understanding this biology, we can very much enhance our health a- and our wellbeing.

   2. AAAli Abdaal0:41

      Hey, friends, and welcome back to Deep Dive, the weekly podcast where every week I have the immense privilege of sitting down with academics and entrepreneurs and authors and creators and other inspiring people, and we find out how they got to where they are and the strategies and tools we can learn from them to help us live our best lives. Now, this episode is very exciting. It is an interview with Professor Russell Foster, who is the professor of circadian neuroscience and head of the Department of Ophthalmology at the University of Oxford. He has recently published this new book, LifeTime: The New Science of the Body Clock and How It Can Revolutionize Your Sleep and Health. And so in this episode, I ask Professor Foster all about the circadian rhythm, the body clock, and all of the different practical, actionable strategies that we can use that take advantage of our circadian rhythms and our body clock to help level up our health in terms of our eating and our exercise and our nutrition and our sleep, crucially. So I hope you enjoy this conversation. What is the difference between

2. 1:33 – 2:56

   What’s the difference between Why We Sleep and LifeTime?

   1. AAAli Abdaal1:33

      your book, LifeTime, and Why We Sleep?

   2. RFRussell Foster1:35

      Fundamentally, I, I approach the, the, the, the, the project really from a circadian basis.

   3. AAAli Abdaal1:41

      Mm.

   4. RFRussell Foster1:41

      So a twenty-four-hour biology. So essentially everything is being adjusted to a, to, to a lesser or greater extent by this internal body clock, our circadian rhythms. Sleep is part of it.

   5. AAAli Abdaal1:52

      Mm.

   6. RFRussell Foster1:53

      And so I've taken a much more sort of global look at our twenty-four, uh, hour biology and made sleep part of that, but not the main focus.

   7. AAAli Abdaal2:01

      Okay. Yeah, 'cause the subtitle, The New Sc- The New Science of the Body Clock and How It Can Revolutionize Your Sleep and Health.

   8. RFRussell Foster2:06

      Yes.

   9. AAAli Abdaal2:07

      I guess, so it's, it's, it's kind of weird. So like, I mean, I, I went through six years of medical school, two years working as a doctor. We did so little on circadian rhythms-

   10. RFRussell Foster2:16

       Yeah

   11. AAAli Abdaal2:16

       ... beyond like a second-year neuro lecture on the eyes. Our eyes are so complicated anyway. It's just like, oh my God, photoreceptors and this and rods. All of, all of the things. That circadian rhythm wasn't-- was very much an afterthought. Sleep was very much an afterthought. Nutrition was very much an afterthought.

   12. RFRussell Foster2:30

       Yeah.

   13. AAAli Abdaal2:30

       And it was only really when I read Why We Sleep that I started to be like, "Oh, circadian rhythms are in fact a thing." And then listening to a few Huberman Lab episodes about it, around kind of getting light in the morning versus not in the evening, it's like, oh, wait a minute, caffeine, adene- and, you know, uh, adenosine and all these things which kind of words that I picked up from medical school but didn't quite apply to the context of how we can actually im-improve our lives. So I guess like what is... what's going on with the, with the, with the body clock

3. 2:56 – 11:12

   How does the body-clock work?

   1. AAAli Abdaal2:56

      broadly? Where do we, where do we start the discussion?

   2. RFRussell Foster2:58

      Well, I th- I think the, the, the remarkable thing for me is that we've spent twenty, twenty-five, thirty years trying to understand how these endogenous twenty-four-hour oscillations are generated. When I started, um, and I, and I moved from the UK to the, to the States, this was the focus. How does the clock tick? And some of the great people, you know, the Nobel Prize in 2017, uh, you know, Rosbash, uh, Hall, a-and Young, would come to University of Virginia, because we're all part of the same National Science Foundation Center for Biological Timing, give talks, and they used to get it wrong a lot. Um, but as the data accumulated and the, and the facts changed, they corrected the story. And so what we had by the Nobel Prize was a pretty complete understanding how you can generate a biological clock, which is completely awesome. You know, essentially you've got a bunch of clock genes which are turned on. They produce a bunch of proteins, they form a complex, they go into the nucleus, they turn those genes off. Um, the proteins are then broken down, uh, and then they're released from this inhibition and can start producing more proteins again. So you have this twenty-four-hour oscillation in protein production and then degradation, and that's the, the, the essence of the clock. And, and certainly, I was involved in early experiments showing that the master clock in the brain is a group of fifty thousand cells called the suprachiasmatic nuclei. And we thought that would drive rhythmicity, uh, and it would impose a twenty-four, twenty-four-hour order on the body. We got that wrong. In a sense, every cell in the body has this internal clock. And so what you've got is a master clock in the brain then coordinating the rhythmic activity of billions of individual cellular oscillators throughout the organ systems of the body, fine-tuning our biology to anticipate the varied demands of activity and rest in the day-night cycle. And so with that exquisite mechanistic understanding and the knowledge, for example, that a single amino acid change in one of those clock genes can either make you a morning person or an evening person is so cool. It's the best system that we have of understanding how genes and their protein products interact to generate behavior. I mean, it's still the best example we have. So, but in parallel with that exquisite mechanistic understanding, which is really my background, um, because I'm interested in how light interacts with the master clock and regulates it, was the appreciation that circadian rhythms underpin almost every aspect of our health and wellbeing. And, and that was the bit I wanted to get across, uh, within, within LifeTime. And that we, in a sense, avoid, um, or ignore these rhythms at our peril. Uh, because if you think about it, for biology to function, it, it, it requires the right materials and the right concentration delivered to the right tissues and organs at the right time of day. And it's the circadian system that actually delivers this extraordinary temporal structure. And so, um, what are the consequences of, of, of, of ignoring this biology as we do for night shift work-

   3. AAAli Abdaal6:17

      Mm-hmm

   4. RFRussell Foster6:17

      ... twenty-four/seven society? And I know that, that wonderful arrogance of being human, I mean, part of our extraordinary, um, achievement has been that we believe that we're independent of the constraints of-

   5. AAAli Abdaal6:28

      Yeah

   6. RFRussell Foster6:28

      ... of the grubby world of biology, and we're not, you know? And it was really-- I think it was a bit of a wake-up call to think, hang on, um, uh, you need to think about this. And it's not all doom and gloom. By understanding this biology, we can very much, uh, enhance our, our health a-and our well-being.

   7. AAAli Abdaal6:46

      Love it. So, okay, so I've, I have so many like specific questions.

   8. RFRussell Foster6:49

      [laughs]

   9. AAAli Abdaal6:49

      But I wonder if we... So if we start more further upstream. So you've got suprachys-suprachysmatic nucleus, where there's fifty thousand cells or so that are sort of the master clock-

   10. RFRussell Foster6:58

       Yeah

   11. AAAli Abdaal6:58

       ... of your body, and they're somehow helping regulate the other billions of cells that we have in the body-

   12. RFRussell Foster7:03

       Yeah

   13. AAAli Abdaal7:03

       ... which also have some level of like circadian rhythmicity to them.

   14. RFRussell Foster7:07

       Yes.

   15. AAAli Abdaal7:08

       What-- Le-let's say it's nighttime for a cell versus daytime for a cell in like, I don't know, the, the, the finger. Like, what difference does it actually make?

   16. RFRussell Foster7:17

       The clocks are, are, sort of made in, in broadly the same way. It-- we don't think there's any fundamental difference in the master clock compared to a finger clock-

   17. AAAli Abdaal7:27

       Yeah

   18. RFRussell Foster7:27

       ... for example. Uh, but their phasing, the alignment of those clocks can be very different. And it's, and it's essentially how they take their reference q-cue from, from the master clock that's important. Now, what you've got is a, uh, a master clock, and it's no use to anticipate these daily changes unless it's set to the real world. And so our interest has been, well, how does the master clock use the dusk-dawn cycle, the light-dark cycle, to regulate internal time? And that's really how I got into this sort of mechanistic side of things and the appreciation that, in fact, it's not the visual cells, the rods and cones-

   19. AAAli Abdaal8:02

       Oh

   20. RFRussell Foster8:03

       ... that are providing this light-dark signal. It's in fact a third photoreceptor in the eye. And so the eye, we can think of it... I mean, it's, you know, obviously the eye is so cool in lots of different reasons, but it's both the organ of, of space through vision, but it's also the organ of time because of its regulation of the internal master clock in the brain. And if you don't have eyes, you are both, um, space blind, but also time blind.

   21. AAAli Abdaal8:28

       Mm-hmm.

   22. RFRussell Foster8:28

       And in fact, we're working with Blind Veterans UK. Uh, those individuals who have radical eye damage or they've lost their eyes, they're, they're drifting through a world without time. These are extraordinary individuals, um, very, very keen to be independent. And some of the, some of the discussions I've had, you know, o-one chap was telling me, "I feel so angry because I, I feel my body is trying to trick me all the time," and went on to tell me about a story whereby he knew that Wednesdays is when he, he cut the grass. And so he woke up, think-- knew it was a Wednesday, 'cause that was the next day, uh, went downstairs and had worked out a way to cut the grass being completely blind. And then, uh, his wife came down and said, "It's three AM in the morning-

   23. AAAli Abdaal9:16

       Mm-hmm

   24. RFRussell Foster9:16

       ... and you're gonna drive the neighbors crazy." And, and it was that incredible sense of frustration. It's essentially, it's a bit like unremitting jet lag for the rest of your life. And so the most recent work that we're doing is, you know, we discover these new photoreceptors, and that's so kinda cool. You've got this, this dual function of the eye. But, but it's really working out how they interact with a molecular clockwork. And we're now at a stage where we've got drugs which can mimic the effects of light on the clock, and the research I'm doing now is to try and develop those drugs so that we can give them to individuals with radical eye disease, no eyes, and give them back a sense of biological time. It's not just actually the profoundly blind. Um, we've done quite a bit of work in the space of, uh, psychiatric illness. So the sleep-wake patterns of individuals with schizophrenia are, are utterly smashed. I mean, I-- to an extent I would never have believed un-until we'd done the studies. And so I also see a role for those drugs in, uh, correcting as an acute corrector of the circadian sleep-wake cycle.

   25. AAAli Abdaal10:22

       Mm-hmm.

   26. RFRussell Foster10:22

       And then hopefully w-not to use drugs and then, then use light-

   27. AAAli Abdaal10:27

       Yeah

   28. RFRussell Foster10:27

       ... but as an immediate corrector. Um, in the context of Alzheimer's and, and dementia, uh, the reason my kids will send me off to a nursing home will be because I'll be wandering around in the middle, middle of the night terrifying the grandchildren, if they ever produce any. Um [laughs]

   29. AAAli Abdaal10:41

       [laughs]

   30. RFRussell Foster10:42

       Um, but no, seriously, uh, if, if we could, um, delay the point a-a-at which one has to sort of send a, an aged relative to the nursing home because of their massively disrupted sleep-wake-
4. 11:12 – 24:53

   How our eyes and light impact sleep-wake cycles

   1. AAAli Abdaal11:13

      Yeah, that's really cool. Um, w-- So how does the-- how do the photoreceptor cell respond, re-- cells respond to dawn and dusk to regulate said master clock?

   2. RFRussell Foster11:22

      Oh, it's such a, it's such a cool question because-

   3. AAAli Abdaal11:25

      Yeah

   4. RFRussell Foster11:25

      ... because they are... I mean, [clears throat] I got into this because I couldn't understand how the visual cells, the rods and cones, which grab light in a fraction of a second, milliseconds, then they forget they've seen that light, and that's how we get an image of the world. Um, and if they, if they took longer, then our con-- our visual world would be a blur as we moved our head. It would be a series-- It would be a smear, not a s- a series of, of sh- of sharp images. And I couldn't see how the rods and cones could extract Dawn-dusk information over long periods of time. And what we did know before we started is that they're really quite insensitive to light, so you needed a lot of light for a long period of time. And I guess having a background in sensory ecology, whereby sensory cells are, are fine-tuned to their de- you know, the demands, the sensory demands, I couldn't understand how a visual cell could also act as a circadian cell. So we started working with mice with hereditary retinal disorders, whereby their visual cells had largely degenerated. They were visually blind. But what was so extraordinary is that when we looked at their ability to regulate their circadian rhythms to a light-dark cycle, and essentially what you do is you put them in a running wheel, like a hamster running wheel, and look when they run and when they don't run, and you get a beautiful readout of their circadian behavior. They could do it perfectly well. When you covered the eyes, then this ability had gone. So there had to be something else in the eye. Now, [clears throat] when we proposed that, um, uh, as I talk about in, in the book, I mean, I remember there was a big, big meeting in the States where I said, "So these data are, are consistent with the fact that there could well be another receptor system in the eye." This person at the back of the auditorium stood up, and I thought, "Okay, well, they're gonna ask a question. Fair enough." And I sort of looked at them, and they looked at me, and they just said, "Bullshit," and walked out.

   5. AAAli Abdaal13:20

      [laughs]

   6. RFRussell Foster13:20

      And, and you know, it-

   7. AAAli Abdaal13:21

      Yeah

   8. RFRussell Foster13:21

      ... got really nasty. I mean, grants were, were hit the deck. One comment from a referee was, "Is Foster seriously telling us that after 150 years of research on the eye, we'd missed an entire light-detecting system?" And so, [laughs] you know, I was a bit younger then, full of, full of, um, I suppose, yeah, arrogance perhaps.

   9. AAAli Abdaal13:44

      Yeah.

   10. RFRussell Foster13:44

       Um, so you know, yes, these, these are the data.

   11. AAAli Abdaal13:47

       Yeah.

   12. RFRussell Foster13:47

       Uh, but it took us a decade to, to get better and better data, ultimately engineering a mouse with absolutely no rods and cones. Um, so you couldn't use the argument, "Oh, well, it's just a few rods and cones left that are mediating this light response." And what we discovered is this entirely genetically engineered rodless, coneless mouse would regulate its responses to light, circadian responses to light perfectly normally, and that led, uh, us to find in a mouse a group of ganglion cells that were directly light sensitive. The ganglion cells are the, are the cells that form the optic nerve of the eye, and about one out of every hundred of those is directly light sensitive. David Berson found the same thing in, in the rat, and Dennis O'Shea found the same thing in, in monkeys. So, you know, after we'd, we'd slogged away for a decade, um, then at about the same time, we in the mice, you know, other people in rats, other people in mice showed, oh yeah, um, there's something else.

   13. AAAli Abdaal14:43

       There's a thing, yeah.

   14. RFRussell Foster14:43

       Um, and that I think has been really incredibly exciting because it's not just cool biology. It has direct clinical application and, and that's where the last gasp of my c- scientific career was going, is, is using that information, uh, hopefully for health and wellbeing.

   15. AAAli Abdaal15:00

       Just a quick message from one of our sponsors, and we'll get right back to the episode, and this episode is very kindly brought to you by Heights. Heights is a braincare smart supplement. It is two capsules that you take every day. I've been taking it for the last 12 months, and it contains over 20 evidence-based micronutrients that you need to keep your brain and body healthy. Like I said, I've been taking Heights every day for the last 12 months, and through that I've actually become friends with the founder, Dan, who we actually had on season one of this podcast. And this season, we also have an interview with neuroscientist and psychiatrist Tara Swart, who is the chief science officer at Heights as well. And one of the things I love about Heights is the fact that every single thing they do is very evidence-based. Over on their blog, on their website, they've got tons of articles along with links to all of the different papers that they've cited that show all the benefits of the various micronutrients that they've got in these two little capsules. And the best thing about taking these is that it is just two little capsules every morning, so you don't have to deal with green sludge or any other kind of faf- faffery. It's just literally taking two pills. It's super easy to sign up. You just go on the website, you put in your address, and they send you either a monthly or a quarterly subscription. I sign up to the quarterly one myself because, A, it's cheaper, and B, I'd have to take fewer deliveries. And if you use the coupon code Ali15 at checkout, that will give you 15% off the already discounted price of the quarterly subscription, so you can try out Heights to your heart's content. So thank you so much, Heights, for sponsoring this episode and for helping improve my own brain care. What was that like when you first did that experiment, covering up the eyes of the mice and realizing, hang on, they lose their circadian activity? Was that like a oh-my-God moment, or was it like a, oh, there must be something else going on here?

   16. RFRussell Foster16:36

       No, it was a, it was a, an oh-my-God moment-

   17. AAAli Abdaal16:38

       Yeah

   18. RFRussell Foster16:38

       ... because it, it was consistent with the sort of theories. Um, but when you had unambiguous data... So the other thing is, of course, my, my background is in comparative biology. I-- My first degree was zoology, and I was, I was aware of weird photoreceptors, so non-mammalian vertebrates have pineal photoreceptors. They have, even have photoreceptors in the hypothalamus. I mean, I know that sounds crazy.

   19. AAAli Abdaal17:04

       Weird. [laughs]

   20. RFRussell Foster17:04

       Huge amounts of light actually g- p- penetrate the brain-

   21. AAAli Abdaal17:07

       Like through the skull?

   22. RFRussell Foster17:08

       Through the skull.

   23. AAAli Abdaal17:08

       Oh, wow, okay.

   24. RFRussell Foster17:09

       Um, and birds, for example, regulate their seasonal biology th- th- that they can detect the increasing and de- decreasing day lengths with a receptor in the hypothalamus. And in fact, I worked on those before I worked on mammals. So the conceptual leap that there could be a weird receptor in the eye wasn't so huge for me 'cause I come from a background of weird photoreceptors. And I think that's a really, really interesting perspective because so much of exciting science is at the interface between different disciplines.

   25. AAAli Abdaal17:40

       Yeah.

   26. RFRussell Foster17:40

       Now, you know- The chap that said we've been studying the eye for 150 years was absolutely dead right.

   27. AAAli Abdaal17:46

       Mm.

   28. RFRussell Foster17:46

       But they'd been studying vision. They hadn't been looking for another role for the eye.

   29. AAAli Abdaal17:52

       Mm.

   30. RFRussell Foster17:52

       And so you find what you're looking for.
5. 24:53 – 29:06

   The impact of the body-clock on health

   1. AAAli Abdaal24:53

      And so once, presumably quite a lot downstream of that, you would have, I don't know, th- uh, the, uh, in the morning the body would decide to be more alert, and in the evening it would decide to be more sleepy. Like, is, is that ultimately what's going on?

   2. RFRussell Foster25:06

      Yeah, I mean, essentially what, what the, the clock is doing is providing a temporal reference cue for all downstream physiology and behavior to, t- to, to align itself. So in anticipation of waking up, the, uh, blood pressure is rising rapidly. Uh, the cortisol levels are rising rapidly. Um, and alertness i- is, is being turned on. And of course, at the other end of the day, those, those physiological and behavioral parameters are sort of declining or going into a different state. I, I think it's important to say that they're not being turned off. They're just going into a different state, because sleep is not a shutting down of biology, as we've sort of con-

   3. AAAli Abdaal25:49

      Mm

   4. RFRussell Foster25:50

      ... you may well have been taught.

   5. AAAli Abdaal25:52

      Yeah. [laughs]

   6. RFRussell Foster25:52

      Um, e- even as recently as when you did your medical degree. Um, but in fact, it's going to a different state, which is, uh, uh, uh, uh, uh, s- in fact, some areas of the brain are more active during sleep than they are during wake. And so what's happening whilst we sleep is that, um, information that we've acquired during the day is then laid to memory. Uh, and, uh, w- in those, those, that new information is then integrated. And so if you want to come up with novel solutions to complex problems, a night of sleep has been shown to hugely enhance our capability of doing that.

   7. AAAli Abdaal26:29

      Mm.

   8. RFRussell Foster26:29

      So the brain is, is sort of not only just sort of s- storing facts-

   9. AAAli Abdaal26:32

      Yeah

   10. RFRussell Foster26:32

       ... it's actually playing with information and coming up with new ideas, which is why sleep is so important, because it's that incredible capacity that humans have of problem-solving, and it's sleep that, that really helps us to do that.

   11. AAAli Abdaal26:45

       Mm.

   12. RFRussell Foster26:46

       At the same time, uh, you know, the brain is regulating the clearance of a whole bange- range of toxins from the, from the body, um, and realigning our metabolic pathways so that the stuff that's been burnt up during the day is then, um, rebuilt at night so we can do it. So it's, it's, it's these wonderful different states of, of, of sleep and wake that are being underpinned, uh, by the clock. And of course, it's immensely complicated, so you have to have that timing, uh, uh, uh, you know, across the day, i- i- a- a- and in space, so the right organs are doing the right things.

   13. AAAli Abdaal27:21

       Just a quick message from one of our sponsors, and we'll get right back to the episode. And this episode is very kindly brought to you by Shortform. Shortform is the world's best service that summarizes books. But it's way more than just book summaries. They almost have a whole study guide for every book that they've got on the platform, where they've got a one-page summary, and then they also have chapter-by-chapter breakdowns. And it's not just chapter-by-chapter breakdowns. Also, in between the chapter breakdowns, they have interactive exercises where you can engage more readily with the ideas in the book. Shortform covers non-fiction books from a bunch of different genres that you might be interested in. For example, they've got a load of stuff in the business world, so if, for example, you're an entrepreneur or you want to become an entrepreneur, that'll be great for you. They've got books in motivation. They've got books in education. They've got books in lifestyle and communication. Basically, any genre of, like, non-fiction, personal development-y, self-help-y stuff that will help you level up your life, it's all there on Shortform. Shortform publishes new book guides and articles every week. And if you're a subscriber, then you get to vote on what book they cover next. And in fact, through that system, I have voted for various books. For example, I've recently revisited the Shortform guide to Atomic Habits by James Clear. I've read the book once, I think, when it first came out when he was interviewed on Matt D'Avella's podcast, and I thought the book was amazing. But to be honest, like with most non-fiction books, once you've got the key ideas from it, rereading the book, especially as sort of, like, in fairly cr- close proximity to your rereadings, doesn't necessarily help, as much as I love James Clear. But the Shortform guide to Atomic Habits is great for revisiting the key ideas. Anyway, if any of that sounds up your street and you would like to sign up to the world's best service that summarizes books, then head over to shortform.com/deepdive, and that will give you a completely free five-day trial, and you can try out the service to your heart's content. That link will also be in the video description and in the show notes. And thank you so much, Shortform, for sponsoring this episode.

6. 29:06 – 44:20

   Debunking sleep myths

   1. AAAli Abdaal29:06

      So I feel like we've got a good, uh, well, a basic kind of grounding in the importance of the circadian rhythm in regulating important aspects of, I guess, physiology and psychology.

   2. RFRussell Foster29:15

      Yeah.

   3. AAAli Abdaal29:16

      Can we talk about sleep now? [laughs]

   4. RFRussell Foster29:19

      Yeah.

   5. AAAli Abdaal29:20

      So, I mean, I read Why We Sleep, and I've listened to a bunch of podcast episodes about this, but I'd just love to get your take on-

   6. RFRussell Foster29:25

      [laughs]

   7. AAAli Abdaal29:25

      ... a few of these, like, frequently asked questions-

   8. RFRussell Foster29:27

      Yeah

   9. AAAli Abdaal29:27

      ... about sleep. So, um, I guess the first one that comes to mind is six hours, seven hours, eight hours, nine hours? What, what's going on there? [laughs]

   10. RFRussell Foster29:37

       Um, I think the key thing for me is that, uh, one shoe size doesn't fit all.

   11. AAAli Abdaal29:44

       Oh, okay. Yeah.

   12. RFRussell Foster29:45

       And, uh, one of the sort of slight frustrations that, that's emerged is that an average value is taken as the optimum value for all of us, and of course it isn't. Uh, across adults, for example- Healthy sleep can range from six hours, maybe slightly less than that, um, out to 10 or 11 hours. And so, yes, there is an average, uh, but actually there's so much individual variation. It's, it's, it's really, I think, wrong to impose a specific amount-

   13. AAAli Abdaal30:20

       Yeah

   14. RFRussell Foster30:20

       ... for each of us. And the point of the book, to some extent, is to allow people to define what's optimal for them.

   15. AAAli Abdaal30:29

       Hmm. How do we do that?

   16. RFRussell Foster30:30

       How do you do that?

   17. AAAli Abdaal30:31

       Yeah.

   18. RFRussell Foster30:31

       So, so how do you know if you're not getting enough sleep? Well, it's, you know, it's the kind of things our grandparents probably would have told us if they-

   19. AAAli Abdaal30:36

       Yeah

   20. RFRussell Foster30:36

       ... asked that question. Which is that, um, do you need a partner or an alarm clock to wake you up in the morning? Does it take you a long time to wake up? Do you crave caffeinated and sugar-rich drinks during the day to keep you awake? Have your friends, family, colleagues reported that you're showing a lack of empathy, increased frustration? They may have noticed that you do stupid and unreflective things. Um, and, and when given the opportunity to s- to sleep, let's say at the weekend and very notably on holiday, do you find your sleep patterns change? And, and it's really defining what each of us needs and then trying to adopt behaviors that defend that sleep pattern.

   21. AAAli Abdaal31:18

       Yeah.

   22. RFRussell Foster31:18

       And, and you know, we know, for example, that the duration of sleep varies enormously between individuals. But not only that, their timing, going back to the molecular clock, uh, there are subtle changes which can make you a morning person or an evening person. But also going, going back to light, that can contribute to what's called your chronotype, your morningness and eveningness. So morning light advances the clock, make you, makes you get up earlier. Evening light delays the clock, makes you get up later and go to bed later.

   23. AAAli Abdaal31:49

       Sorry, e-evening light as in?

   24. RFRussell Foster31:50

       Dusk light. So dusk delays, um, morning advances the clock.

   25. AAAli Abdaal31:56

       Oh.

   26. RFRussell Foster31:56

       So you're constantly being nudged backwards and forwards.

   27. AAAli Abdaal31:59

       Yeah.

   28. RFRussell Foster31:59

       And of course, one of the problems of our society is that we don't get asymmetrical exposure to light, which, um, can be a problem.

   29. AAAli Abdaal32:08

       Asymmetrical as in?

   30. RFRussell Foster32:08

       Uh, as in you, you're not getting an equal amount of advancing and delaying dawn, dusk exposure. So we looked at a bunch of, uh, university students around the world.
7. 44:20 – 50:14

   The importance of morning light

   1. RFRussell Foster44:20

      Um, yeah.

   2. AAAli Abdaal44:20

      When you, so when you say morning light, um, are we talking, like, what sort of time are we talking?

   3. RFRussell Foster44:24

      Yeah.

   4. AAAli Abdaal44:24

      What sort of lux? Like, what's, what's going on there?

   5. RFRussell Foster44:26

      It's, it's outside light is, is what we really need. Uh, and I think it's because the visual system is so good at, uh, adapting to different light levels, uh, we're not really aware of the fact that we live in dim, dark caves. Most, uh, sitting rooms, uh, offices, you'll be lucky to get three, four hundred lux of light intensity, whereas right by a window, you'll get on average three thousand lux. Uh, shady env- environment will be m- maybe 10,000 lux, 20,000 lux. Bright sunny day, 80 to 100,000 lux.

   6. AAAli Abdaal45:03

      Oh, that's a huge difference between-

   7. RFRussell Foster45:04

      Huge difference

   8. AAAli Abdaal45:04

      ... even just being indoors versus outdoors.

   9. RFRussell Foster45:05

      Yeah, a- absolutely.

   10. AAAli Abdaal45:06

       Nice.

   11. RFRussell Foster45:06

       And so that's why morning light, uh, outdoor light is so good. Th- th- and it may be the explanation, for example, why individuals with dogs, um, have reported to sleep better because, of course, they have to get up, take them for a walk in the morning, and they're getting their, their morning photon shower. Um, and that's helping consolidate the sleep-wake rhythms of not only themselves, of course, but the dog.

   12. AAAli Abdaal45:29

       And are we talking, like, 5:00 a.m. morning or, like, 10:00 a.m.? Like what sort of morning are we talking?

   13. RFRussell Foster45:32

       No, we're talking, we're, we're talking, I suppose, you know, 7:00, 8:00 in the morning. I mean, the, certainly, the earlier you get up, uh, if you got up at 5:00 a.m., you would have a, a big advancing effect upon the clock. But most of the time, we're talking about a mild modulation of the... We're just nudging it to keep on track because, uh, on average, and again, I don't like to use averages, but, but the, the Harvard group have suggested that the human body clock is around about 24 hours and 12 minutes and 10 minutes. So we only need a slight adjustment-

   14. AAAli Abdaal46:03

       Hmm

   15. RFRussell Foster46:03

       ... uh, every day, so it's not a huge adjustment. Unlike, of course, when we cross multiple time zones, and then we've got one heck of a shift-

   16. AAAli Abdaal46:12

       Yeah

   17. RFRussell Foster46:12

       ... 'cause, you know, we're eight hours or six hours or going to Australia, you know, to, or New Zealand, 12 hours of time difference. And of course, it takes about a day for every, uh, time zone we've crossed to adjust, s- you know, fully adjust. So it's a, it's a, it's a... A- and, and again, it goes back to that wonderful molecule SCN1A, which is buffering the effects of light on the clock because, of course-

   18. AAAli Abdaal46:36

       Yeah

   19. RFRussell Foster46:36

       ... it makes sense. It doesn't want evolutionarily huge shifting of the clock. It doesn't want it to be disturbed because, for example, you might then, if you're a m- a, a, a burrowing mammal-

   20. AAAli Abdaal46:48

       Yeah

   21. RFRussell Foster46:49

       ... uh, emerge from your, your burrow too late or too early and be somebody else's lunch.

   22. AAAli Abdaal46:54

       Yeah. So it sound, it sounds like broadly, even though we don't like to give prescriptions to people, but going for a walk in the morning feels like a very reasonable-

   23. RFRussell Foster47:01

       Yes

   24. AAAli Abdaal47:02

       ... good thing to do.

   25. RFRussell Foster47:02

       And having your breakfast right by a window.

   26. AAAli Abdaal47:05

       Oh, okay, yep.

   27. RFRussell Foster47:05

       So, you know, the nursing home environment-

   28. AAAli Abdaal47:06

       Yeah

   29. RFRussell Foster47:07

       ... uh, where it's many individuals don't get out very much and where sleep-wake is really awful in some cases. And indeed, the light environment, um, as van Someren, a wonderful colleague from the Netherlands, you know, put in the nursing home environment, big banks of lights of producing a thousand to 2,000 lux, um, darkness in the bedrooms, and con- consolidated really ragged sleep-wake profiles into much more robust sleep-wake profiles. And what was interesting is that those individuals who showed, um, a stable sleep-wake profile, uh, their cognition went up by almost 10%.

   30. AAAli Abdaal47:42

       Ooh, nice.
8. 50:14 – 51:29

   Seasonal Affective Disorder (SAD)

   1. AAAli Abdaal50:14

      Um, so there's a lot of people that get kinda seasonal, seasonal affective disorder.

   2. RFRussell Foster50:17

      Yes.

   3. AAAli Abdaal50:18

      Is that basically a light intensity thing from what we know?

   4. RFRussell Foster50:20

      It seems to be. I mean, I think many of us were very skeptical when this was, you know, seasonal affective disorder was, was, was first talked about because what's the control? You know, you can't see-

   5. AAAli Abdaal50:31

      Yeah [laughs]

   6. RFRussell Foster50:31

      ... somebody in front of a light box, you know, without the lights on 'cause they kinda get it. Um, and then the studies became much more effective and compared morning light versus evening light, and we've talked about the importance of morning light. Morning light was much more effective, uh, at regulating SAD than evening light, and very specifically blue light, which is where those photosensitive retinal ganglion cells are maximally sensitive, um, was more effective than other wavelengths, other colors-

   7. AAAli Abdaal50:58

      Mm

   8. RFRussell Foster50:58

      ... in reducing the effects of, of, of SAD. Um, a- and, and so I think it, it's a real phenomenon. Friends who are psychiatrists don't think it is. They think, "Oh, it's just another form of, you know, um, of, of, of anxiety or, or, or, or depression." Um, but, but I think the data are now sufficiently strong to show that there's a, there's a genuine light effect.

   9. AAAli Abdaal51:20

      Yeah.

   10. RFRussell Foster51:21

       Um, precisely what the mechanism is, we don't know. Um, what we do know is it's not melatonin.

   11. AAAli Abdaal51:28

       Hmm.

   12. RFRussell Foster51:28

       And so we were

9. 51:29 – 1:02:02

   Understanding melatonin

   1. RFRussell Foster51:29

      talking about myths earlier.

   2. AAAli Abdaal51:30

      Yeah.

   3. RFRussell Foster51:30

      So, so melatonin is often called a sleep hormone. It is emphatically not a sleep hormone.

   4. AAAli Abdaal51:35

      Oh, okay. What is it? [clears throat]

   5. RFRussell Foster51:36

      It's a biological marker of the dark.

   6. AAAli Abdaal51:39

      Okay.

   7. RFRussell Foster51:39

      Which means... So if we, if we, again, if, if, if we can go back to my roots-

   8. AAAli Abdaal51:43

      Please, yeah. [laughs]

   9. RFRussell Foster51:44

      Um, and, and the comparative, what we know about melatonin in mammals is that the expanding seasons, so the increasing dark length in the autumn and winter leads to an increasing, uh, release of melatonin. So melatonin maps the seasonal changes in light and dark. And what, uh, a sheep or a deer or something will do is use that increasing melatonin profile in the autumn to trigger reproduction so that there's the breeding and there's, um, uh, the young are gestating over the winter-

   10. AAAli Abdaal52:18

       Yeah

   11. RFRussell Foster52:18

       ... and they're born in the March when there's lots of, lots of fresh vegetation to sustain milk production and weaning. Um, so that's, that's the really exquisitely understo- u- understood role of melatonin. Melatonin, if you look at individuals who are on beta blockers and you, you reduce their levels of melatonin by over 80%-

   12. AAAli Abdaal52:39

       Mm

   13. RFRussell Foster52:39

       ... then sleep is not, is, is not really affected. If you look at quadriplegics-

   14. AAAli Abdaal52:44

       Why beta blockers?

   15. RFRussell Foster52:45

       Uh, because it blocks the, um, sympathetic regulation of the pineal gland, which then regulates the output of melatonin.

   16. AAAli Abdaal52:52

       Oh, fine. Okay.

   17. RFRussell Foster52:52

       So it's, it's, you know, it's quite interesting that-

   18. AAAli Abdaal52:54

       Yeah

   19. RFRussell Foster52:54

       ... that people on beta blockers, um, do show, um, almost no melatonin release. But, but the interesting studies... And again, you have to read the papers. So there's a study showing quadriplegic individuals, those people who've tragically, you know, severed their spinal cord, you know, at the level of the neck, have n- nothing, you know, below, below the neck, um, have terrible sleep. Um, and that's the argument was originally, well, it's because they're not producing any pineal melatonin. Uh, then you compare those individuals to paraplegics, um, who of course can regulate their pineal melatonin production. They also have terrible sleep, and it's not different from the quadriplegics. So it's, it's the, the, the ghastliness of losing sen- you know, of not being mobile, um, that's the problem with the sleep, not the lack of melatonin. And in the best studies ever undertaken, taking melatonin before you go to bed can reduce the time it, uh, takes to get to sleep by 30 minutes. And I stress, that's the best study ever undertaken. Many studies showed no effects whatsoever.

   20. AAAli Abdaal53:57

       Hmm.

   21. RFRussell Foster53:57

       So melatonin-

   22. AAAli Abdaal53:58

       Sorry, by best study do you mean the most-

   23. RFRussell Foster54:00

       The most ef- the, the one that was the-

   24. AAAli Abdaal54:01

       ... the most positive study-

   25. RFRussell Foster54:02

       Exactly. The one with the most-

   26. AAAli Abdaal54:03

       ... as opposed to the best conducted study?

   27. RFRussell Foster54:03

       Exactly.

   28. AAAli Abdaal54:04

       Okay, got it.

   29. RFRussell Foster54:04

       Yeah, the one, the one that, that showed the most, the greatest efficacy would be the-

   30. AAAli Abdaal54:07

       Right
10. 1:02:02 – 1:07:11

    Should we use devices before bed?

    1. RFRussell Foster1:02:02

       um, issue I have. And, and so if you read the press, uh, then looking at a Kindle-

    2. AAAli Abdaal1:02:09

       Hmm

    3. RFRussell Foster1:02:09

       ... before you go to bed, uh, is an absolute disaster because it'll, it'll change your sleep-wake timing. Um, there are data that looked at this. So the Harvard group got people to look at a Kindle on its brightest intensity for four hours just before bedtime on five consecutive nights, and it just statistically delayed sleep onset by 10 minutes.

    4. AAAli Abdaal1:02:34

       Oh, perfect, because I read Kindle before bed. [laughs]

    5. RFRussell Foster1:02:36

       Well, yeah. As, as one of my-

    6. AAAli Abdaal1:02:37

       On a dim orange light setting, but yeah. [laughs]

    7. RFRussell Foster1:02:39

       Well, one of my colleagues said, "Well, it may be statistically significant, but it's biologically meaningless."

    8. AAAli Abdaal1:02:43

       Right. [laughs]

    9. RFRussell Foster1:02:44

       So going back to the, you know, our point earlier, which is you need a lot of light for a long duration to actually affect the clock. Um, and so these devices, the, the, the Kindles are producing 30 lux.

    10. AAAli Abdaal1:02:57

        Oh, okay.

    11. RFRussell Foster1:02:57

        Um, now you can get an effect on the clock with 200 lux or so, but you need six and a half hours of exposure.

    12. AAAli Abdaal1:03:09

        [laughs] Right.

    13. RFRussell Foster1:03:10

        So, so again, it's titrating intensity and duration.

    14. AAAli Abdaal1:03:14

        Yeah.

    15. RFRussell Foster1:03:14

        So there will be a slight wobble, um, but it's gonna be very mild.

    16. AAAli Abdaal1:03:19

        Hmm.

    17. RFRussell Foster1:03:19

        And of course, if you're getting morning natural light, it's gonna correct any evening wobble. Um, so for most devices, the light is not the issue. It's the alerting effect.

    18. AAAli Abdaal1:03:29

        Hmm.

    19. RFRussell Foster1:03:30

        And where we have really nice data are for smartphones, for example, which have this incredible alerting effect, not least in teenagers, and, uh, that will, uh, increase levels of alertness and therefore delay sleep onset. R- lovely, lovely anecdote. I mean, I remember speaking to, um, a young lad, and I said, um, uh, "Not smart, you know, to, to look at your, your, your smartphone, um, uh, uh, uh, before you go to bed." He said, "Look, look, you know, uh, it's okay. With my computer, I-- my smartphone, I've got a device, uh, which changes the color from blue to, to red, so it's just not a problem for me, okay?" And I said, um, "Okay. Well, there's not really much evidence that that has much of an effect at all."

    20. AAAli Abdaal1:04:12

        [laughs]

    21. RFRussell Foster1:04:12

        "Um, and by the way, what time are you getting to sleep?" He said, "Well, about 2:30 in the morning." [laughs]

    22. AAAli Abdaal1:04:17

        Yeah. [laughs]

    23. RFRussell Foster1:04:18

        And so you can actually fool yourself that you're protecting yourself with a, with a screen that changes its color.

    24. AAAli Abdaal1:04:24

        Yeah.

    25. RFRussell Foster1:04:24

        And actually it's not having an effect at all other than, you know, it's on, on, on the clock. It's essentially this alerting effect that it does. And many young people are aware that this is not a smart idea, but the, uh, anxiety of being disconnected from social media and their friend circle is overwhelming. And, and so, so it's, it's-- you know, our advice is always, "Look, you know, try and be disciplined about it."

    26. AAAli Abdaal1:04:53

        Yeah.

    27. RFRussell Foster1:04:53

        And I know how difficult it is. We talked about Australia. I-- those of you who remember BlackBerrys, I, I just got my BlackBerry, and you may remember it used to have one of those g- red lights that used to sort of glow when there was a message. So I had my Australian emails. Um, that was fine. And then the European ones would come in, um, which of course would be bedtime, and then the American ones would come in, which of course would be-

    28. AAAli Abdaal1:05:21

        Yep. [laughs]

    29. RFRussell Foster1:05:21

        ... even later. And so I, I know I, I'm weak like everybody else.

    30. AAAli Abdaal1:05:25

        Yeah.
11. 1:07:11 – 1:08:06

    Is it better to wake up without an alarm?

    1. RFRussell Foster1:07:11

       It's such a shame.

    2. AAAli Abdaal1:07:12

       So is it better for you to wake up without needing an alarm, or are alarms totally reasonable?

    3. RFRussell Foster1:07:17

       I- if you're waking up naturally without an alarm, it's telling you you probably had a good night's sleep. You also may wake up remembering your dream because, of course, we go through a series of stages, which is the, sort of the non-REM, REM cycle. REM standing for rapid eye movement sleep, uh, which is when the, when you're sort of essentially paralyzed from the neck down and your, and your eyes... If you've got a sleeping partner, it's just, it's sometimes fascinating to see, you know, the eyes wobbling behind the, um, the, the eyelids. If you don't have a sleeping partner, then, well, you can see it in your dog or whatever. Um, and it's just an incredible state. But it's during REM sleep that, uh, we have our most vivid, uh, uh, dreams, and we wake naturally from REM sleep. So those individuals who are waking up in the morning naturally are much more likely to remember their, their dreams.

12. 1:08:06 – 1:09:08

    Understanding dreaming

    1. AAAli Abdaal1:08:06

       Mm.

    2. RFRussell Foster1:08:06

       And while we're talking about dreams, um, I think it's really important to stress, uh, there's nothing to worry about with dreams.

    3. AAAli Abdaal1:08:12

       Yep. [chuckles]

    4. RFRussell Foster1:08:13

       Uh, dreams are a way of, um, the brain probably trying to make sense of, uh, our emotions and, uh, struggling with what we may or may not have experienced, uh, you know, during the previous few days. They do not anticipate things. Um, I mean, it's, there's no evidence for that whatsoever. But they do seem to be associated with our emotional status. So, for example, after the Twin Towers were destroyed, uh, there were lots of dreams, not of seeing planes crash into the buildings, which is interesting because that was the image that was constantly on the television. But people had anxiety dreams of being mugged, being overwhelmed by a tsunami.

    5. AAAli Abdaal1:08:59

       Mm.

    6. RFRussell Foster1:08:59

       So, so, so yes, our dreams do reflect our emotional status, but you shouldn't be worried about them because it's the brain trying to work through these issues.

13. 1:09:08 – 1:18:20

    Blue light and warm light

    1. AAAli Abdaal1:09:08

       Um, just on the point of the whole, uh, blue light, yellow light thing.

    2. RFRussell Foster1:09:12

       Yeah.

    3. AAAli Abdaal1:09:13

       You know, the, every device these days seems to have a nighttime setting where-

    4. RFRussell Foster1:09:17

       Mm-hmm

    5. AAAli Abdaal1:09:17

       ... they'll suddenly go orange and-

    6. RFRussell Foster1:09:20

       Yes

    7. AAAli Abdaal1:09:20

       ... I guess that lulls us into a false sense of security. Oh, it's not too bad using my computer at, like, midnight because it's, it's, it's orange.

    8. RFRussell Foster1:09:25

       I think that's the thing.

    9. AAAli Abdaal1:09:26

       Yeah.

    10. RFRussell Foster1:09:26

        It's, um, there's very little evidence that that shift in wavelength color will have any effect upon the clock. Um, color is only important, um, w-w-when, uh, under certain circumstances. Um, uh, if, if the light is bright, it doesn't really matter what the color is.

    11. AAAli Abdaal1:09:43

        Okay.

    12. RFRussell Foster1:09:43

        Um, and we can talk about blue ga-

    13. AAAli Abdaal1:09:45

        Yeah

    14. RFRussell Foster1:09:45

        ... glasses in a moment. Uh, so yeah, I think it does lull us into a false sense of security, and you just need to stop using, uh, these, these devices. Uh, it, it could well have a mild effect-

    15. AAAli Abdaal1:09:57

        Mm

    16. RFRussell Foster1:09:57

        ... because after all, these cells are maximally sensitive to the blue part of the spectrum. But you're so low-

    17. AAAli Abdaal1:10:03

        Yeah

    18. RFRussell Foster1:10:03

        ... that it probably just doesn't matter much.

    19. AAAli Abdaal1:10:05

        Okay. It's more about the alerting.

    20. RFRussell Foster1:10:06

        It's the loading. It's-- Yeah, exactly.

    21. AAAli Abdaal1:10:08

        Right.

    22. RFRussell Foster1:10:08

        It's, it's, it's the alerting effect, um, of, of the content that you're processing and, uh, and it may well be some contribution of the alerting effect of light. It looks as though the, the threshold for regulation of the clock is higher. You need more light to regulate the clock than you would to have an alerting effect. Ironically, what's the last thing that most of us do? Which is stand in the most brightly lit room in the house, the bathroom-

    23. AAAli Abdaal1:10:34

        Mm

    24. RFRussell Foster1:10:34

        ... you're looking into an illuminated mirror-

    25. AAAli Abdaal1:10:36

        Yeah

    26. RFRussell Foster1:10:36

        ... while we clean our teeth. And I've, I've often thought there's a commercial opportunity to have a bathroom mirror with a bright morning light setting-

    27. AAAli Abdaal1:10:44

        Yeah

    28. RFRussell Foster1:10:44

        ... to increase alertness as, before we leave the, leave the house. Um, and, um, to slightly dim it to reduce alertness before, um, [chuckles] before we go to bed.

    29. AAAli Abdaal1:10:54

        Yeah. Yeah, so in the, in, in the place I'm at at the moment, there's a, um, a dimmer switch in the bathroom.

    30. RFRussell Foster1:10:58

        Ah.
14. 1:18:20 – 1:20:28

    Having a winding down routine before bedtime

    1. RFRussell Foster1:18:20

       than any [laughs] --

    2. AAAli Abdaal1:18:21

       Yeah. Rather than, uh, specific subcortical structures.

    3. RFRussell Foster1:18:22

       Any, any cortical structures. Yeah. [laughs]

    4. AAAli Abdaal1:18:25

       Yeah. So like, oh, I'm just gonna t-

    5. RFRussell Foster1:18:26

       Yeah

    6. AAAli Abdaal1:18:26

       ... I'm lighting my candles.

    7. RFRussell Foster1:18:27

       It's, it's related, you know-

    8. AAAli Abdaal1:18:27

       It's my wind down routine. It's nice. I'm gonna sleep soon

    9. RFRussell Foster1:18:29

       ... for s- and, and actually, you know, uh, we're joking, but-

    10. AAAli Abdaal1:18:31

        Yeah

    11. RFRussell Foster1:18:31

        ... but actually developing a, a wind down r-routine at the end of the day is really important before you go to bed. And if it's, you know, candles that, that, that do it and, and even sort of some form of smell, whether it be, you know, lavender or, uh, something else, uh, the evidence that, that sort of, um, oils actually do have an effect above placebo is not very good. In fact, it's negligible. Uh, but if it works, then I think that's, that's fine.

    12. AAAli Abdaal1:19:02

        Mm.

    13. RFRussell Foster1:19:02

        It's, it's like, it's like a-any relaxation techniques, I mean, I have to say in the early days when people were sort of getting peddling, um, mindfulness, I sort of put it in the box of crystal waving. Um-

    14. AAAli Abdaal1:19:13

        [laughs] Right

    15. RFRussell Foster1:19:14

        ... and that's, you know-

    16. AAAli Abdaal1:19:14

        Yeah

    17. RFRussell Foster1:19:14

        ... kind of my grumpy sort of background as a f- you know, really I want mechanisms, I want physiology, I want to understand how it actually works. And then actually I got in-- I, I sort of studied it a bit and I realized essentially what mindfulness is, is a brilliant way of finding relaxation techniques, and relaxation techniques work. Um, we don't understand necessarily the mechanisms, but they do work. And so at the end of the, the day, trying to get rid of the stresses, um, then I think relaxation techniques, whatever they are, can be extremely useful. I mean, in our house- I ban the discussion of family finances, you know? And, and it's a shame because it's often the only time of the day that you-- couples do have chance to talk about come sort of serious issues because you get up, you rush off to work, you know, you then get your dinner, and then you have that sort of period-

    18. AAAli Abdaal1:20:06

        Mm

    19. RFRussell Foster1:20:06

        ... of relaxation.

    20. AAAli Abdaal1:20:07

        Mm.

    21. RFRussell Foster1:20:07

        But actually what you don't want to fill that time with is angst-promoting discussions. Um, and so I think trying to find a time, um, maybe at the weekend where you can have those discussions is so important, but not immediately before you go to bed. My wife still tries, though. [laughs]

    22. AAAli Abdaal1:20:24

        Oh, yeah. [laughs] Family finances. Um, what's--

15. 1:20:28 – 1:27:22

    How stress impacts sleep

    1. AAAli Abdaal1:20:28

       Uh, so you talk on-- in, in the book a little bit about stress and the effects of stress on-

    2. RFRussell Foster1:20:33

       Yeah

    3. AAAli Abdaal1:20:33

       ... like, uh, how does stress and body circadian rhythms and sleep and stuff interact?

    4. RFRussell Foster1:20:37

       I think this is such an important point. Um, most people don't have a sleep problem. They have a sleep or anxiety problem. And so, you know, the, the, the, the worry that they have is preventing them getting the sleep that they, they, they need. Um, and I think while we're talking about it, it's worth distinguishing between sleepiness and fatigue. Sleepiness is cured by the opportunity to sleep. Um, fatigue is you can be sleeping a lot longer, but you're still feeling tired, exhausted, um, lacking energy, um, during the day.

    5. AAAli Abdaal1:21:14

       Yeah.

    6. RFRussell Foster1:21:15

       And, uh, so many people with COVID, for example, had fatigue. They had long periods of sleep, but they were still feeling exhausted-

    7. AAAli Abdaal1:21:23

       Mm

    8. RFRussell Foster1:21:24

       ... and below par. And what fatigue represents is an underlying health issue, um, which is different from sleepiness.

    9. AAAli Abdaal1:21:32

       Mm.

    10. RFRussell Foster1:21:32

        So if you, you get persistent fatigue, then there's a chance you have some underlying health issue which you need to get explored. I, I was chatting to, to somebody in the States just recently, and she was telling me that, um, she was feeling tired all the day. She couldn't, couldn't work. Um, and then she'd go to bed, and then she'd wake up in the night. Um, uh, and of course, ideally, you'd fall back to sleep, but she was so, uh, alarmed at all the stuff she'd failed to do during the day, she couldn't then get back to sleep. And it transpired, actually, she had an immune problem-

    11. AAAli Abdaal1:22:07

        Hmm

    12. RFRussell Foster1:22:07

        ... which of course was leading to her fatigue. And so, so sorting out the immune issue, which was causing the fatigue, which then was causing the anxiety-

    13. AAAli Abdaal1:22:17

        Mm

    14. RFRussell Foster1:22:17

        ... which was then stopping her sleep. And so I think it's really important to try and dissect all of these things. You know, what's does stress do? It increases blood pressure. It increases levels of alertness. You know, it pumps out the cortisol and adrenaline. It makes us more alert. And so if you are stressed, it's gonna be tricky to sleep. And so that's why it's so important to make that detachment at the end of the day from the things that have upset you. You know, mindfulness, anything, y-yoga, what-whatever. Um, and of course, the problem during COVID and since is that many people's bedrooms have become their places of work, uh, because the bedroom has where you can set up your office.

    15. AAAli Abdaal1:22:59

        Yeah.

    16. RFRussell Foster1:22:59

        And that's of course, it, it is-- there may, for many people, be no other possibility. But by combining your sleeping space with your workspace, it means that your opportunity to sleep is going to be affected by, "Oh, um, maybe I should just, just check the email again, you know, before I go to sleep," or whatever. Or if you wake up, you know, the tendency is, "Oh, I'll just, just check if those, those emails came in from the, from the States." And it has such an alerting effect, you won't go back to sleep. So if you do have to have your office in your bedroom, you've gotta be really disciplined, turn everything off, and make it a real pain to have to turn it on, um, if you happen to wake in the night.

    17. AAAli Abdaal1:23:39

        Yeah. So I, I guess, um, do you know, like, what the data is around-- I mean, I've, I've heard that, uh, acute stress is kinda good for you, but like chronic stress is like bad for you.

    18. RFRussell Foster1:23:47

        Yeah.

    19. AAAli Abdaal1:23:48

        Yeah.

    20. RFRussell Foster1:23:48

        I think that, that's a really important point. And, and I have likened stress to a bit, bit like, um, the gears of a, of an engine.

    21. AAAli Abdaal1:23:55

        Hmm.

    22. RFRussell Foster1:23:55

        So, uh, acute stress is like first gear. It gives you that wonderful acceleration. You can get away and do your stuff. But if you leave the engine in first gear, chronic stress-

    23. AAAli Abdaal1:24:04

        Hmm

    24. RFRussell Foster1:24:04

        ... then you're gonna destroy the engine. And that's, I think, a very interesting analogy because, yes, stress-- And we give s- you know, um, stress a, a bad time, but actually it's evolutionarily really important. It gives us that massive acceleration to get out of problems. You know, the fight or f-flight response. But it's where we have to keep on turning that mechanism on to function, and that's what tired people do. A night shift worker, their entire biology, um, is in the sleep mode. It's really important to stress that night shift workers, ninety-seven percent of night shift workers, do not adapt to the demands of working at night. So they're working against an entire biology-

    25. AAAli Abdaal1:24:44

        Mm

    26. RFRussell Foster1:24:44

        ... which is saying, "You should be asleep." And the override for that, of course, is turning on the stress axis.

    27. AAAli Abdaal1:24:51

        Mm.

    28. RFRussell Foster1:24:51

        Which of course has-- whi-which explains why long-term night shift work is associated with such chronic health conditions: coronary heart disease, um, type 2 diabetes. You know, what are you doing when you, when you turn the stress axis on? You're throwing glucose into the circulation to try and burn it up 'cause you're gonna need it for running away or fighting. Now, if you're not, then it just-- you become glucose intolerant.

    29. AAAli Abdaal1:25:16

        Yeah.

    30. RFRussell Foster1:25:16

        Um, so obesity, same thing. Um, higher rates of cancer in night shift workers because what happens? One thing we know about high levels of, of cortisol, they'll suppress the immune system, making you more vulnerable to not only infection, but cancer.
16. 1:27:22 – 1:34:10

    Exercise, eating and temperature

    1. AAAli Abdaal1:27:22

       so we've talked a little bit about stress. Um, what's... Uh, how does, how do, how does, I guess, exercise relate to our circadian rhythm?

    2. RFRussell Foster1:27:30

       Yeah, that's, um, interesting. First thing is that part of the sleep mechanism is a drop in core body temperature. Uh, and individuals... If, if, if you block that drop in core body temperature, it's more difficult to get to sleep. Um, and it's only about a drop in, of, of about a degree. So if you exercise, uh, late, fairly shortly before you go to bed, you're going to increase core body temperature, and it might be more difficult to get off to sleep.

    3. AAAli Abdaal1:28:00

       Mm.

    4. RFRussell Foster1:28:01

       Um, exercise, uh, depends why, why you want to exercise. If you want to burn calories, then there's, there's two, two ideas. That because n- nighttime we're in a different metabolic status, so during nighttime, um, we are burning stored calories, and we're mobilizing those calories to keep metabolism going throughout the sleeping state. During the day, we're taking calories in, and we're metabolizing those calories and, and, and burning them up, ideally. So if you want to exercise before breakfast first thing in the morning, you're still in the sleep metabolic status, so you're burning up, um, stored calories, which for some people is what they want to do. Trouble is, our ability to exercise increases throughout the day. So most track records, swimming records, other athletic performance is peaking in the late afternoon and early evening.

    5. AAAli Abdaal1:29:01

       Mm.

    6. RFRussell Foster1:29:01

       So you'll notice, uh, and, and people at the Olympics know this, so the finals are always late afternoon, early evening, 'cause that's when individuals can exercise for longer with greater power.

    7. AAAli Abdaal1:29:14

       Yeah.

    8. RFRussell Foster1:29:15

       So if you want to, um, i-... So if you're a more of an evening person, as I am, then I am likely to be a-- well, I will be able to exercise for longer and exert greater power, um, later in the day than first thing in the morning. Now, if you're a morning person, getting up and doing your exercise before breakfast, that's great. For those of us who would find that particularly difficult-

    9. AAAli Abdaal1:29:37

       Yeah

    10. RFRussell Foster1:29:37

        ... uh, then I think, uh, uh, late afternoon and early evening is, is where you go.

    11. AAAli Abdaal1:29:44

        Yeah. I try, I tried so hard to be a kind of wake up early in the morning, go to the gym before going to work kind of guy, but I would always find that it would just be such a chore, and I wouldn't look forward to it, and I'd be like, "Ugh, why am I doing this? This is the worst thing ever." And now when I go to the gym at, like, 5:00, 6:00 PM-

    12. RFRussell Foster1:29:57

        Yeah

    13. AAAli Abdaal1:29:57

        ... I'm having a great time.

    14. RFRussell Foster1:29:58

        That's it.

    15. AAAli Abdaal1:29:58

        Yeah.

    16. RFRussell Foster1:29:58

        I think that's it. You find out really what works b- best for you. A- and, a- a- and you know, it's, it's, it's interesting because it relates to eating. Um, our, our habits, our eating habits have changed profoundly, um, with the Industrial Revolution. Uh, during the 1100s or so, the main meal of the day was breakfast. During the Middle Ages, 1100 to 1500, it shifted to noon, and I mean 12 o'clock, 11, 12 o'clock, and that's where the main meal of the day... And we think of all those Tudor banquets, you know, with people throwing-

    17. AAAli Abdaal1:30:33

        Oh, yeah

    18. RFRussell Foster1:30:34

        ... chicken legs all over the place. Um, that was actually at lunchtime-

    19. AAAli Abdaal1:30:37

        Right

    20. RFRussell Foster1:30:37

        ... not in the evening.

    21. AAAli Abdaal1:30:38

        Not dinner, yeah.

    22. RFRussell Foster1:30:39

        But with, uh, the industrialization and that the workspace was, was different from the living space, and commutes and all, and all the rest of it, our main meal of the day, many of us will run out the door with breakfast, maybe a tiny breakfast. We probably don't have time for lunch, so we may have a sandwich in front of the computer, and then we'll get home after a, a long commute, shove something in the microwave, um, and then we'll be massively calorie... You know, having a massive calorie load, you know, late in the day. And what's been shown is that there's a circadian regulation of our metabolism. So the same... There was a wonderful study looking at, um, the same meal at 8:00 AM versus 8:00 PM, and those individuals who, uh, same, same people, but when they had the meal at 8:00 PM, circulation levels of glucose were 17% higher than the same meal at 8:00 AM.

    23. AAAli Abdaal1:31:35

        Okay.

    24. RFRussell Foster1:31:35

        And of course, leading, later in the day, high levels of glucose-

    25. AAAli Abdaal1:31:38

        Yep

    26. RFRussell Foster1:31:39

        ... uh, greater risk of diabetes II, obesity, and all the rest of it. So when you eat is really important, and the data now are, are very, very persuasive. Um, so yeah.

    27. AAAli Abdaal1:31:50

        Oh, wow. So my late-night Five Guys is, like, worse than my mid-afternoon Five Guys. [chuckles]

    28. RFRussell Foster1:31:55

        Absolutely.

    29. AAAli Abdaal1:31:55

        Oh, wow. Okay, cool.

    30. RFRussell Foster1:31:56

        Yes. Yes, yes.
17. 1:34:10 – 1:37:26

    Morning and evening people

    1. AAAli Abdaal1:34:10

       Oh

    2. RFRussell Foster1:34:10

       ... and advising them.

    3. AAAli Abdaal1:34:11

       Uh, we talked a little bit, um, uh, earlier about kind of morning person, evening person-

    4. RFRussell Foster1:34:14

       Yeah

    5. AAAli Abdaal1:34:14

       ... and the idea of chronotype.

    6. RFRussell Foster1:34:16

       Yes.

    7. AAAli Abdaal1:34:16

       Uh, how does one figure out their chronotype?

    8. RFRussell Foster1:34:19

       It's not that difficult. There are questionnaires, um, that you can fill in.

    9. AAAli Abdaal1:34:23

       I think you've got one in the appendix, yeah.

    10. RFRussell Foster1:34:23

        Yeah, there's, there's a, there's a, there's a questionnaire in LifeTime, which is a well-validated questionnaire, and it basically asks you, you know, your preferences to a whole bunch of things. And, uh, I think it, it raises, uh-- I think it's interesting if you know your chronotype because it might help you explain certain aspects of your behavior. But, but certainly I've also wanted to encourage employers to take chronotype into account. So if you're on the night shift, it would make an awful lot of sense if you had a later chronotype versus a morning chronotype. And, uh, not that you would remove a- all of the problems of, of night shift work, but if you could match your workforce, um, and, uh... So, so for example, I've, I've urged banks, um, to say, "Right, you know, this is 24/7 business. Why don't you develop teams whereby they're the morning types-

    11. AAAli Abdaal1:35:15

        Hmm

    12. RFRussell Foster1:35:15

        ... the middle types, uh, and they're called larks, doves-

    13. AAAli Abdaal1:35:18

        Yep. [chuckles]

    14. RFRussell Foster1:35:19

        ... and, and owls."

    15. AAAli Abdaal1:35:20

        Right.

    16. RFRussell Foster1:35:20

        But there are a whole bunch of other animals that are being used as well for these cla- classifications. I like the old, you know, um, larks-

    17. AAAli Abdaal1:35:27

        Yep

    18. RFRussell Foster1:35:27

        ... and doves and owls. Um, and then you've got a, a team that can span, uh, the, the 24/7 banking sector that, that will make it easier. I mean, you know, you put the, the, the, the owls on the, on the, um, American, uh, when the, when the American banks are at their peak, and, you know, the, the larks will be when the Asian banks are at their peak. And I think that working together across chronotypes could be really valuable.

    19. AAAli Abdaal1:35:53

        Yeah. 'Cause there's a lot of, like, moralizing about the whole wake up at 5:00 a.m. and you are better than the sort of person that wakes up at 11:00 a.m. kind of thing. [chuckles]

    20. RFRussell Foster1:36:00

        Oh, God.

    21. AAAli Abdaal1:36:00

        Yeah.

    22. RFRussell Foster1:36:01

        It's just that whole machismo of, you know... And of course, those of us that remember the '80s, you know, people would bounce in and say, "Oh, I've done another all-nighter." And, you know, people used to slap them on the back, and that's just nonsense. I mean, would you want in the workplace people who were lacking in empathy, overly impulsive-

    23. AAAli Abdaal1:36:16

        [chuckles]

    24. RFRussell Foster1:36:17

        ... and incapable of making, um, sensible decisions? No. I mean, and, you know, and that's the consequence of not getting enough sleep. And so, uh, yeah, I think that... I, I think those days, hopefully, mercifully are gone. Uh, although, uh, I understand the banking community, there was a survey last year, uh, and some, I think, young bankers were saying, "We're gonna resign." If you put... You know, there's huge working hours, you know, completely stressed. I think, uh, uh, the majority, uh, were getting less than five hours sleep a night, um, uh, which, which, uh, maybe a fraction wouldn't, you know, could, could cope on that generally, but most would not. And, and of course, do you really want the people looking after our pensions and our national economies-

    25. AAAli Abdaal1:37:02

        [chuckles]

    26. RFRussell Foster1:37:02

        ... you know, overly impulsive, uh, uh, and failing to make, uh, sen-

    27. AAAli Abdaal1:37:06

        And lacking in empathy. [chuckles]

    28. RFRussell Foster1:37:07

        [chuckles] And making sensible decisions about the economy? No. Um, so I would... You know, in the same way that the medical profession has, to some extent, ignored the impact of night shift work-

    29. AAAli Abdaal1:37:17

        Mm-hmm

    30. RFRussell Foster1:37:17

        ... I think the, the financial sector is another sector that really needs to start to take it seriously.
18. 1:37:26 – 1:48:53

    Building an optimum sleep schedule

    1. RFRussell Foster1:37:26

       yeah.

    2. AAAli Abdaal1:37:26

       Um, 'cause it seems like you haven't really consulted them, but I wo- I wonder what's, what's on them.

    3. RFRussell Foster1:37:28

       Well, well, I-

    4. AAAli Abdaal1:37:29

       Yeah.

    5. RFRussell Foster1:37:29

       So, so if o- one was gonna structure, you know, what, what could you do, um, to develop sort of an optimum sleeping regime?

    6. AAAli Abdaal1:37:38

       Oh, perfect. [chuckles]

    7. RFRussell Foster1:37:39

       Uh, okay.

    8. AAAli Abdaal1:37:40

       Yeah.

    9. RFRussell Foster1:37:40

       Um, so then I think you can divide, you can divide sort of the, the day into four sections. I mean, so, so during the day, um, we've talked about light. For most of us, 90% of us, it would be getting morning light to set the clock. What about napping? Um, so, uh, a 20-minute nap in the early afternoon has been shown to be effective. So the occasional nap, you know, can, can make you function better during the second half of the day. And some, uh, companies, you know, offer a 20-minute nap. Longer than 20-minute nap, you, you can drop into a deeper level of sleep, and then recovery from that, the sleep inertia that you experience can make you groggy, and it can be counterproductive. But a short nap can be effective.

    10. AAAli Abdaal1:38:22

        And are we, are we talking 20 minutes of actual sleeping or...?

    11. RFRussell Foster1:38:25

        Um, uh, te- yeah. I mean, you, you basically, um, will, will set your timer for 20 minutes, you know, and if you're Tired, you need a nap-

    12. SPSpeaker1:38:32

        Yeah

    13. RFRussell Foster1:38:32

        ... you'll probably fall asleep for most of that. There's a big problem though for teenagers. So they, for reasons we've discussed, ha- tend to have shortened sleep. So they're, they're going to sleep, they're waking up chronically tired, and when you talk to teachers, you know, there are kids falling asleep at their desk. They then get home, they then will sleep for two or three hours, relatively close to bedtime. That pushes back sleep pressure, which means it's more difficult to get to sleep that night. So you fall into a cycle of later delayed sleep, um, shortened sleep, and then extended, not naps, but really sleeps during the day. So you need to be careful you don't fall in, into, into that cycle. Um, so, so napping can be useful occasionally, you know, that's fine. Exercise, again, we've touched on not too close to beds- be- bedtime because of course it can raise core body temperature, but the key thing is to exercise. Um, concentrating food intake during the first and middle parts of the day. Why? Well, of course, if you're having your calorie intake towards the end of the day, you're much more likely to lay it down as fat. You are more likely to have conditions like obstructive sleep apnea, which can massively, um, harm your sleep at night.

    14. SPSpeaker1:39:50

        Mm.

    15. RFRussell Foster1:39:51

        So, you know, that's one thing to be careful of. Uh, avoid excessive consumption of caffeine. So many of us will not drink coffee after 2 or 3 o'clock in the afternoon. Caffeine has a long half-life. I mean, for, depending on who you are, five to nine hours. So, you know, a, a late afternoon cup of coffee can again delay sleep, um, at that night. Um, when you leave work or when you stop work, you've got to make time to step back and switch into another mode, uh, some sort of relaxation. You mentioned going to the gym. That's, that's great. It's doing something that is completely different from your, your, your, your work. So that's sort of things you can think about during the day. Before bed, reduce the light. Again, we've touched on this. It's not because it's gonna have a big effect upon the clock. Light will have an alerting effect, so minimize light exposure 30 minutes before you, uh, go to bed. Stop using electronic devices. Again, same thing. You need to be winding down. Uh, i- ideally, avoid prescription, uh, sedatives. It's really important to, um, be aware that sleeping tablets are sedatives. They do not provide a biological mimic for sleep. You know, basically, they, um, en- encourage a, a neurotransmitter which turns off all of those alerting neurotransmitters in the brain. And it's been shown that it can reduce, for example, memory consolidation and, uh, can promote daytime sleepiness, particularly in the elderly. And sleeping tablets are really not recommended, uh, for things like dementia and stuff like that. Um, alcohol. Many people will, uh, have a, have a, have a sort of a cycle of excessive coffee during the day to keep themselves awake and then sedate themselves with al- alcohol at night. Really bad idea. Alcohol is a, again, a sedative. It can disrupt the n- natural pattern of REM, non-REM sleep, and it can, again, harm memory consolidation and the processing of, of, of information. Uh, again, we've touched on this [chuckles] before you go to bed, avoid discussing topics that have a stressful or alerting effect upon you. Um, and then finally, you know, before bed, it's wind down. And whether it's reading that Kindle, which works for you, um, whether it's listening to a piece of classical music, whether it's listening to Radio 4 Extra, whatever it is, you know, what works for you. So that's sort of during the day and before bed. The bedroom itself shouldn't be too warm. Again, we've talked about this loss in core body temperature. If the bedroom is too warm, it's much more difficult to get off to sleep. Again, ideally, it should be quiet. Now, that's tricky. Of course, in many sort of apartments and flats, people have used white noise or relaxing sounds such as whale song or the sea. And again, try it out. It, it, it may work. Uh, dark, uh, if possible, and particularly if you're, um, getting a lot of street lighting through, you can get blackout curtains that can go behind your normal curtains. As much as you possibly can, remove TV, computers, all of those sorts of alerting effects be- you know, from the bedroom space. As, as we've discussed, really tricky because many bedrooms have become also offices. So make it difficult to turn those devices on. Um, don't clock watch. Uh, again, we've touched on this. Uh, the illuminated, uh, dial on your clock can be used if you wake up, think, "Oh my God, I've only got a few hours before I have to get up." Doesn't matter, so, so, so cover it up. Uh, and of course, don't use your smartphone, so maybe just go back to an old mechanical clock. Although I'm, I'm told that the tick-tock now for some people drives them completely crazy. Um, sleep apps. Uh, don't take sleep apps seriously. Uh, n- again, as we've discussed, none of them are endorsed by the national sleep federations. They can be deeply misleading and, uh, can actually make you more anxious about your sleep. What they're useful for is telling you roughly when you went to sleep, how many times you woke in the night, and when you woke up.

    16. SPSpeaker1:44:08

        Mm.

    17. RFRussell Foster1:44:08

        That can be useful because if you want to change your sleep timing, uh, or your sleep duration, then you can modify your behaviors and then have a, a, a accurate record of that with your app.

    18. SPSpeaker1:44:19

        Yeah.

    19. RFRussell Foster1:44:20

        Uh, so in the same way, if you want to lose weight, you can change your eating behavior, you weigh yourself in the morning, you see a change in weight, and that reinforces your, your changed eating behavior.

    20. SPSpeaker1:44:29

        Mm.

    21. RFRussell Foster1:44:29

        Uh, but don't start getting obsessive about, "Ooh, I had a good, good night's sleep," or, "I had lots of slow wave sleep." They're just not accurate enough at the moment, uh, to give you that information. Um, then, of course, in bed, uh, again, try to keep to a routine. Go to bed and get up at the same times. Ensure that the bed is comfortable and large enough. I, I do feel that, uh, we Brits are kind of cheap about our bedding. Um, you know, it's a third of our lives, and yet we're very reluctant to spend on, you know, de- decent mattresses and pillows. And of course, it depends on who you are. Go try them out.

    22. AAAli Abdaal1:45:05

        Yeah.

    23. RFRussell Foster1:45:05

        Talk to friends, family about that sort of thing. But I do think it's important to, to, to take it seriously and invest in good bedding. Keep bedsides lights low. Again, you can read comfortably, but you don't have to have them too bright, because it'll have an alerting effect. Now, some people sort of define the sleeping space with relaxing oils, uh, such as lavender, uh, and that can be useful. The evidence that it actually works is not great. Uh, but what also people might do is if they're traveling a lot, they may take, um, their partner's aftershave or, or, or perfume and then define the sleeping space, uh, you know, for them in a foreign place, which can, can aid, aid sleep. So that's, that's, that's fine. Earplugs. Now, this is a really interesting area. If your partner snores, then uh, earplugs is, is one solution. Many people can't cope with earplugs, and so I recommend, if you can, finding an alternative sleeping space. Now, that idea for many, particularly, um, sort of older couples, is, is the, the, the, the sort of the signature of death of a relationship.

    24. AAAli Abdaal1:46:22

        [laughs] Yep.

    25. RFRussell Foster1:46:22

        It absolutely isn't. Whether you sleep in the same bed or not, it does not define the quality of your relationship, and I would argue, in fact, if you're getting a b- better night's sleep in a room next door, you'll be more empathetic, you'll have more fun together, um, and, and you'll be a better person. You're a b- better person. So, so don't worry if y- if you feel you need to sleep elsewhere. That, as I say, doesn't define your relationship. What you do need to be very careful about is that your partner doesn't have obstructive sleep apnea, and that's where there's a, a cessation, a stopping of breathing for a period of time, and then they'll wake up with a gasp and so on. Now, that's really serious. And, and basically what obstructive sleep apnea is, is a collapse of the musculature of the throat, which actually blocks the, the, the breath- the breathing channels, um, which means you're depriving the brain of oxygen. It detects it's not getting the oxygen it neeves-- nee- needs, and it so will then wake you up. Uh, now, but that great surge in blood pressure with that waking up has been associated with, uh, damage to the small vasculature within the eye and the brain. And of course, those individuals with obstructive sleep apnea have higher rates of, uh, coronary heart disease and all the rest of it. Uh, exactly cause and correlation is unclear, but you do need to get it looked at. It's, it's a serious issue. Um, it's been estimated that a very large number of those individuals, uh, running our, our, driving our, our buses and trains have obstructive sleep apnea, causing, of course, daytime sleepiness and all of the other health areas. So, so get that looked at. And it can-- A- and I mean, CPAP, which is this sort of forced air, uh, mask, can take a little of time to get used to, but it works in over ninety percent, uh, of cases. So it's, it's fixable. Um, and finally, as we have discussed, if you wake, stay calm. Um, it's not necessarily the end of sleep. You just need to maybe, if you're not falling back to sleep immediately, go to another space, um, and relax, and then return to, return to the bed when you feel, when you feel, um, uh, able to sleep again. Uh, the key thing is, uh, there's lots of things that you can try. Sleep, so many people think is sleep is what you get, and w- and it's not. We can have a lot of control over our sleep if we're not anxious about it. And as soon as you've found something that works for you, stick to it.

    26. AAAli Abdaal1:48:50

        Mm-hmm.

    27. RFRussell Foster1:48:50

        Defend your sleep.

    28. AAAli Abdaal1:48:52

        Love it.

19. 1:48:53 – 1:52:16

    Advice for students and young people

    1. AAAli Abdaal1:48:53

       Firstly, thank you so much. This has been wonderful. Um, I guess final thing I'd like to sort of, uh, end with is, you know, you're-- you've had a pretty illustrious career. You're a professor now. You teach all these students. Uh, we have a lot of students and young people listening or watching to this, uh, to this podcast. I guess, what would be your top tips for if you were, if you were able to have a, a platform to advise young people about anything or other for, I guess, succeeding in life, staying happy, healthy?

    2. RFRussell Foster1:49:20

       Yeah, I think it's very-- it's really important, um, that we get education about the importance of sleep and circadian rhythms embedded, uh, within our schools. Uh, and, and just making the point that, uh, if you don't get enough sleep, then you're going to have a negative view of the world. There's some really amazing studies showing that tired people, um, remember, uh, the negative experiences but forget the positive ones. So, you know, it's difficult enough being young, uh, as it is, but, but only remembering the ghastly stuff that's going on rather than the good stuff m- means your worldview is completely changed. Knowing that not having enough sleep, you know, you're gonna be more irritable, you're gonna be more anxious, um, that you'll have loss of empathy. You'll show greater levels of frustration. You'll show increased tendency to use stimulants and then sedatives. Uh, you'll have decreased cognitive performance. You know, this is the time of one's life when you're packing in, you know, your educational opportunities. And not embracing one's education because of lack of sleep is a terrible squandering of, of resources. Um, you'd have poor memory and concentration without good sleep. Uh, you'll have impaired decision-making capacity, um, a- a- and creativity. So all the sorts of things that make us this extraordinary species, you know, humor, um, the ability to, to absorb and use information, all of this is in-- i- is, is inhibited by sleep. And you'll also show reduced social connectivity. So, so sleep is not an indulgence. It's not a luxury. It's something that is thirty percent of our biology or more and needs to be embraced, and it makes you a happier, healthier, lovelier person. And it means what you can do is, I suppose, embrace all of the opportunities that the world has to offer. And not getting enough sleep is kind of a terrible squandering of, of, of opportunity.

    3. AAAli Abdaal1:51:24

       Fantastic. Professor Foster, thank you so much. This has been wonderful.

    4. RFRussell Foster1:51:26

       Great pleasure.

    5. AAAli Abdaal1:51:26

       Uh, where can people learn more about you if they would wanna, wanna follow up more of your work?

    6. RFRussell Foster1:51:30

       Oh, well, there's, there's LifeTime, of course, which I've ju- just finished. So, uh, um, you know, uh, much of what we've discussed is, is in LifeTime. Uh, and then you can track me down on our website, the Sleep and Circadian Neuroscience Institute at the University of Oxford.

    7. AAAli Abdaal1:51:44

       Brilliant. Thank you so much.

    8. RFRussell Foster1:51:45

       Great pleasure. Thank you.

    9. AAAli Abdaal1:51:46

       All right, so that's it for this week's episode of Deep Dive. Thank you so much for watching or listening. All the links and resources that we mentioned in the podcast are gonna be linked down in the video description or in the show notes, depending on where you're watching or listening to this. If you're listening to this on a podcast platform, then do please leave us a review on the iTunes store. It really helps other people discover the podcast. Or if you're watching this in full HD or 4K on YouTube, then you can leave a comment down below and ask any questions or any insights or any thoughts about the episode. That would be awesome. And if you enjoyed this episode, you might like to check out this episode here as well, which links in with some of the stuff that we talked about in the episode. So thanks for watching. Uh, do hit the subscribe button if you aren't already, and I'll see you next time. Bye-bye.

Episode duration: 1:52:16