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Dr. Guy Leschziner: Pursuing perfect sleep worsens insomnia

Leschziner explains why chasing perfect sleep is making insomnia worse; he walks through CBT-I, light timing, and why a third of life evolved for sleep.

Dr. Guy LeschzinerguestSteven Bartletthost
Jul 1, 20241h 58mWatch on YouTube ↗

EVERY SPOKEN WORD

  1. 0:00 – 2:15

    Intro

    1. GL

      I've seen patients cooking a meal in their sleep-

    2. SB

      Whoa.

    3. GL

      ... who've driven in their sleep, committed crimes in their sleep.

    4. SB

      So what is the story of Kenneth Parks?

    5. GL

      He drove several miles to his in-laws' house, bludgeoned his mother-in-law to death, and then tried to kill his father-in-law. But it was deemed he was sleepwalking, and he was actually acquitted.

    6. SB

      That's crazy. Dr. Guy Leschziner is a leading neurologist and sleep physician at one of Europe's largest sleep clinics.

    7. NA

      And with over 25,000 studies of over 100,000 patients, his pioneering research in sleep medicine has provided the answers we need to improve our sleep.

    8. GL

      So many people are chronically sleep-deprived. 30% will experience insomnia, and 80% of people in the UK don't know that they've got sleep apnea. This is the problem. But the majority can be helped.

    9. SB

      So let's get into that. Is there such a thing as healthy sleep?

    10. GL

      Somewhere between seven and eight and a half hours a night. Now, what's difficult to explain is why your all-cause mortality goes up if you're sleeping more than eight and a half hours.

    11. SB

      Is there a link between sleep deprivation and weight gain increases?

    12. GL

      So even a single night of sleep deprivation can result in a dramatic increase in calorie intake, and that's because ..........................

    13. SB

      What hope would you offer insomniacs?

    14. GL

      There are very effective treatments for insomnia. For example, if you ... we know that helps about 80% of individuals.

    15. SB

      Are you a fan of sleep tablets?

    16. GL

      As a general rule, no, because there are many non-drug-based techniques.

    17. SB

      What are these techniques to improve our sleep?

    18. GL

      The gold standard treatment now is ...

    19. SB

      Guy, why do we dream?

    20. GL

      That's a really important question. The honest answer is ...

    21. SB

      We've just hit six million subscribers on the Diary of a CEO, um, so me and my team would like to do something we've never done before as a little thank you, and we're calling it the Diary of a CEO Subscriber Raffle, and here is how it works. Every episode this month, we're going to pick three current subscribers at random, and we'll send one of you a 1,000 pound voucher, one of you tickets to come and watch the Diary of a CEO behind the scenes live with our team, and one of you will have a 10-minute phone call with me to discuss whatever you want to talk about. If you're a subscriber, you're in the raffle. Thank you from the bottom of my heart for allowing me to do something that me and my team love doing so much. It is the greatest honor of my lifetime, and I hope it, I hope it continues, uh, off into

  2. 2:15 – 4:15

    Dr. Guy's Fascination With Neurological Conditions

    1. SB

      the future. Let's get to the episode. (instrumental music) Guy, or should I say Dr. Guy, what is it that is at the very sort of heart of your personal curiosity? Because as I look at your work and how, what you've committed your career to, there seems to be a bit of a through line as to sort of the subject matters that have captured you.

    2. GL

      So, I've always been fascinated why we are the way that we are. And obviously, from a scientific perspective, the core of that is our brain. And in the course of my clinical practice, I come across a, a whole host of individuals who really sit at the extremes of the human experience, you know, people who are sometimes afflicted by very serious, uh, neurological conditions, who experience the world in a very different way to how we do. So really, the, the, at the core of what I do, particularly in the public-facing work that I do, it's looking at those people at the extremes of the human experience and trying to work out what it tells us about all of us, about how we all work.

    3. SB

      When you say, "The extremes of the human experience," what does, what does that mean?

    4. GL

      So individuals who have, who see the world in a very different way, experience the world in a very different way, understand the world in a very different way, so you know, from when it comes to individuals who have very extreme sleep disorders to individuals in whom the perception of reality is very different from our own, or to people who behave in a very different way. So when it comes to things like, uh, aggression or, um, the way, their relationship with food or, um, their personality traits, I think in, in every area of clinical neurology, you see individuals in whom something has happened to their brain that fundamentally changes the way they see the world, interpret the world, or behave within that world.

  3. 4:15 – 6:26

    What Is Dr. Guy's Background

    1. GL

    2. SB

      And what's your sort of day-to-day, and, and als if I was to take a look at your CV, what would I see on your CV?

    3. GL

      I, uh, studied medicine at Oxford and then at Imperial, uh, and very early on in my career started training in the world of neurology. Did a PhD at Imperial in Cambridge.

    4. SB

      What is neurology?

    5. GL

      Neurology is the clinical study of the brain, so the brain in its diseased state. So we see individuals with epilepsy, with Parkinson's disease, with nerve problems, um, with s- certain types of sleep disorders, basically any disease or disorder that influences how the brain and the nervous system works. So I did a PhD at Imperial in Cambridge looking at the genetics of epilepsy, and then started working, uh, as an NHS consultant in 2010.

    6. SB

      And you're a consultant of neur-, um, neurology and sleep medicine?

    7. GL

      That's right, yeah.

    8. SB

      I've never heard the phrase "sleep medicine" before.

    9. GL

      Well, sleep medicine has been around for a long time. Um, I was very lucky in that early on in my training period I rotated through a hospital where one of my now colleagues had actually come from the United States. He'd been based in LA where sleep medicine was really starting out, and he'd set up a, a sleep medicine unit, and that was at, uh, St. Thomas' Hospital in London opposite the Houses of Parliament. Um, and certainly over the last 20 or 30 years, it's been a really exploding area of, uh, of medicine, uh, partly mirrored by the fact that we are much more aware of the impact of sleep on a, a range of biological and m- uh, mental health issues. Um, but actually, in the world of neurology, there are many-... sleep disorders that have their basis in the brain, conditions like narcolepsy, like people who sleepwalk or act out their dreams, people who have, uh, episodes at night that may or may not reflect certain types of epilepsy. So, that's really the primary focus of my work now.

  4. 6:26 – 8:01

    What Is A Sleep Disorder Centre?

    1. GL

    2. SB

      Between 2013 and 2023, you ran Guy and St Thomas' Hospital Sleep Disorder Centre.

    3. GL

      That's right, yeah.

    4. SB

      What is that?

    5. GL

      So, the, the Sleep Disorder Centre is probably one of the largest sleep disorder centers in Europe, actually. So we have 10 in-patient beds, so that every night, 10 people are brought into the sleep laboratory and we study their sleep. It's got, uh, now about 15 consultants, it's got a staff of about 50 people, and we see a range of people with conditions like sleep apnoea, which is where people stop breathing at night, and then some of the conditions that I- I've talked about, conditions like restlessness leg syndrome, extreme sleepwalking, narcolepsy, and other related issues.

    6. SB

      How many patients have you had in your sleep disorder centre that you've studied?

    7. GL

      Gosh. Uh, an awful lot. So we do about 2,500 sleep studies a year, and we've been going for, well, a long time, sort of 15, 20 years. So every year we see about, uh, 10,000 patients in total, so very, very large numbers.

    8. SB

      If you had to estimate, how many have you seen?

    9. GL

      I- I- I would imagine somewhere in the region of upward of 100,000 if we're talking about 10,000 patients a year.

    10. SB

      And, and how many sleep studies have you conducted in that centre?

    11. GL

      (inhales deeply) So we've been at the current site with 10 beds for about 10 years.

    12. SB

      Mm-hmm.

    13. GL

      Um, and so we're probably talking about 25,000 studies.

  5. 8:01 – 9:19

    Why Dr. Guy Chose To Study Sleep

    1. GL

    2. SB

      Why sleep? Of all the things that you could commit so much of your time to, 'cause it appears you've been really thinking and working on the subject matter of sleep for about, sort of, 20-odd years, two decades roughly?

    3. GL

      Yeah, something like that, yeah.

    4. SB

      Wh- why?

    5. GL

      Well, I think the first thing is, is that, um, we spend a third of our lives doing it, and yet we, whatever people like me will tell you, we still understand relatively little about it. We understand relatively little about, you know, what it's for, um, what it does to our biology. Uh, obviously that's changing very, very quickly now. Um, it's, uh, it has a great deal of overlap with the world of clinical neurology, so I also do, uh, ID specialist clinic in, uh, uh, specialist clinics in epilepsy and ID specialist cl- uh, clinics in, in general neurology. So, and, and sleep and the brain intersect at every single level. Of course, you know, it's not me saying this, but a famous statement is sleep is of the brain, by the brain, and for the brain. It's in- intimately linked to every aspect of how our brain works. So one of the really exciting things is that because it's a relatively new area, our understanding of it is exploding in ways that are not paralleled across other areas of clinical medicine.

  6. 9:19 – 11:24

    Is Sleep Important?

    1. GL

    2. SB

      Is it important?

    3. GL

      Is it important?

    4. SB

      Yeah.

    5. GL

      Um, I- I think it is of fundamental importance. You know, the fact is that if sleep wasn't important, it would be a very stupid thing for evolution to create in us, the fact that we are essentially slight- switched off from our external environment for a third of our lives. And actually there's a whole host of evidence when you look at how, um, certain animals have developed the ability to be able to sleep with only half their brain at a time, you know, animals like aquatic mammals or certain birds-

    6. SB

      Like a dolphin.

    7. GL

      ... and dolphins, that very much suggests, well, you know, that must be of great importance if it's, if sleep is, um, a risk for our survival. Because if you're an-

    8. SB

      Mm-hmm.

    9. GL

      ... aquatic mammal like a dolphin and you're sleeping and you're unable to surface or unable to see what predators are around you, that the, the, the, the evolution has designed a system whereby it enables you to sleep with half of your brain at a time. So that in and of itself tells us that it's important. The, the, the fact that the circadian rhythm, so that 24-hour cycle that a whole host of biological rhythms have, is so intrinsically linked to life itself that actually every single, um, life form exhibits features of this 24-hour circadian rhythm tells us that this was something that was prioritized at a very, very early stage in life's evolution on Earth. So yes, it's important, and over the last few years we've understand- understood precisely why it's important. I say precisely, but we know that it's important for pretty much every aspect of our waking lives, be it our immune system, be it our, um, cardiovascular system, our blood pressure, risk of diabetes, um, uh, mental health, so depression and anxiety, even how we perceive pain. So it really is fundamental to every system that we, uh, rely on during our waking lives.

  7. 11:24 – 12:59

    Why We Need Sleep For Good Health

    1. GL

    2. SB

      Having seen, you know, thousands and thousands and thousands of people that struggle with sleep that have been sent to your centre, do you think the, the average person on the street over or underestimates the importance of sleep in their day-to-day life?

    3. GL

      Well, I think it's changing. I think it was not that long ago where, you know, comments like, "Sleep is for wimps," uh, was heard fairly frequently, and that there were some bragging rights associated with how little you sleep. I think that there has been a transformation over the last sort of 15 or 20 years whereby people have become much more aware of how important sleep, uh, sleep is, and have started prioritizing it a little bit.

    4. SB

      So you think w- w- where do you think we stand, then? Overestimate, underestimate?

    5. GL

      I think that there is still in the general population an underestimation of how important sleep is, but I think there are certain-... uh, segments of the population that are much more aware of it and perhaps even, dare I say, overestimate it.

    6. SB

      Overestimate it?

    7. GL

      Yes, I think so.

    8. SB

      Interesting.

    9. GL

      I, I think that there is a danger at the current time that we tend to obsessionalize about sleep and, um, a- a- and think that it is the, the be-all and end-all. It's, of course, part of normal life for our sleep to fluctuate depending on what's going on in our external and our internal lives. And I think the danger is that if you overemphasize the important of, importance of getting eight or eight-and-a-half hours sleep every night, then you actually, uh, risk problems later down the line, exacerbating things like insomnia.

  8. 12:59 – 17:05

    A Large Percent Of The Population Has Insomnia

    1. GL

    2. SB

      Can you give me an overview of the current state of sleep in terms of the percentages, stats of people that are struggling with their sleep, the variety of ways that we struggle with our sleep, the different disorders associated with, with our sleep, and just, like, a breakdown of society at large's current sleep health?

    3. GL

      So we think that about 20% of the adult population are chronically sleep-deprived, so that they are not sleeping enough, and that's largely as a result of lifestyle factors and lack of prioritization of sleep. We think... We know that about 30% of the adult population in any one year will experience a period of insomnia. So, insomnia is different from chronic sleep deprivation. Insomnia is the, the state whereby you want to sleep, where you're lying in bed and you can't sleep, which is very different from, you know, burning the candle at both ends. And about 10% of the adult population will have chronic insomnia, so that's an ongoing issue with not being able to sleep for m- more than three months at a time. So, you know, very, very high numbers. There are some other sleep disorders that are incredibly common, so a condition called obstructive sleep apnea, which is essentially, uh, part of the spectrum of, of snoring. But in obstructive sleep apnea, your airway narrows, uh, you have difficulty breathing, it partially obstructs, and you have recurrent brief awakenings, sometimes that you're not aware of, that disrupt your sleep. And estimates were... vary wildly depending on where in the world that they've been done, but I think, you know, our best guess is something like 10 to 12% of adult males experience sleep apnea, clinically significant sleep apnea, and somewhere in the region of about 6% of, of women experience clinically significant sleep apnea. So we're talking about very, very large numbers, and the majority of individuals with sleep apnea are undiagnosed. So it's estimated that about 80% of people in the UK with sleep apnea don't know that they've got sleep apnea and have never seen anybody about sleep apnea. There are other conditions like, um, restless leg syndrome, which is a neurological disorder whereby people, uh, experience an urge to move, uh, a fidgetiness in their... usually their legs, although it can affect other body parts as well, um, that can give rise to very huge difficulties getting off to sleep and actually staying asleep, because a lot of these individuals kick at night when they are asleep and kick themselves awake. And that probably affects somewhere in the region about 5% of the adult population. Even sleepwalking, 1 to 2% of the population. So lots and lots of these conditions. Very, very common.

    4. SB

      How many of the people that walk in your sleep center do you think could be helped and could you help?

    5. GL

      Well, I think the majority can be helped. Um, a cure is something different, but the majority can be helped in some shape or form.

    6. SB

      And if, and if we talk about getting someone that has walked in your clinic with some kind of sleep disorder to a state where they are a healthy sleeper, what kind of percentage do you think?

    7. GL

      Well, I think it's important to, to precede what I say by the fact that actually we don't see many people with insomnia.

    8. SB

      Okay.

    9. GL

      We tend to divert people with what we term primary insomnia or, or, or insomnia without any underlying causes to a sister service. If you look at insomnia, chronic insomnia as a whole, we know that there are some very good treatments for chronic insomnia, and actually, uh, most of those treatments are focused on non-drug-based treatments, psychological-based treatments. And we know that those kinds of treatments will significantly improve sleep in up to about 80% of individuals. So that's a very large number, actually. And there are other treatments available. It doesn't just rely on these non-drug-based treatments. There are some conditions like, for example, narcolepsy, um-

    10. SB

      Which is... What's narcolepsy?

    11. GL

      So narcolepsy is a, a, a brain disorder that is triggered by your immune system.

    12. SB

      Is that where you fall asleep during the day?

    13. GL

      It's when you fall asleep very, very quickly during the day. You're

  9. 17:05 – 18:03

    What Is Narcolepsy

    1. GL

      excessively sleepy. You have very vivid dreams. You will often hallucinate as you drift off to sleep or as you wake up. You'll experience something called sleep paralysis, where you wake up and you feel that you are completely paralyzed, you cannot move. And a, a lot of these individuals also experience a condition called cataplexy, which is where, usually with strong emotion, like laughter, sometimes it can be the telling of a joke, and they lose muscle strength and will sometimes collapse to the ground. So it's a very pure neurological disorder because we know precisely where that ar- area of immune attack occurs within the brain, and it knocks out a very small number of brain cells to generate this. This is a... You know, once you have it, at the moment, it's a lifelong condition, but actually it can be treated. There are many treatments available, and even in the last five years or so, there have been many new treatments that have become available. So actually, all of these conditions are treatable, they're manageable. Um, they're not necessarily all curable.

  10. 18:03 – 21:06

    What's Causing So Many Sleep Problems?

    1. GL

    2. SB

      Is there something at the heart of culture and how we're living that's causing so many of us to struggle with sleep?

    3. GL

      The way that modern society is at the moment certainly, I think, is rather conducive to insomnia. In fact, you know, when-... uh, researchers have looked at, um, a- a- at pre-industrialized societies, so, you know, for example, um, tribes in, um, i- in- in Eastern Africa or in- in South America, actually insomnia is relatively w- rare, and some of these tribes don't even have the word for insomnia. So I think that there's certainly ... insomnia seems to be correlated with the changes that have occurred in our, in our society. Sleep apnea is often associated with weight gain, and obviously that is very much a function of our modern societies. So yes, it undoubtedly, some of these conditions can be attributed to the way that we lead our lives. Some are not.

    4. SB

      Has anybody ever put, like, a sleep tracker on a tribe?

    5. GL

      Yes. That has been done. There's a chap called, uh, Jerry Siegel who's based in the East Coast in one of the Ivy League universities who has spent his life doing that.

    6. SB

      And what did he find out?

    7. GL

      So, he found out that actually sleep does vary a little bit a- according to the seasons, that, uh, they don't necessarily sleep all the way through the night, but actually their sleep is rather different to the sleep of modern society.

    8. SB

      In what way?

    9. GL

      They will not necessarily ... So this view that we sleep when it gets dark and, or used to sleep when it gets dark and wake up at, at, at dawn is incorrect. Um, that they, uh, that there is some fluctuation between the seasons, but not necessarily, um, uh, you know, directly related to the number of hours of daylight, and that insomnia is relatively rare.

    10. SB

      When ... So th- are they waking up in the middle of the night, then, by this?

    11. GL

      Uh, I, I think it's normal to wake up in the middle of the night, that we all wake up in the middle of the night. It's very rare that you, uh, for example, do a sleep study on somebody and you don't see periods of awake in the middle of the night. It's normal to be awake for up to about 30 minutes over the course of the night. That in itself is not a marker of pathological sleep.

    12. SB

      Wh- when I say awake, I mean, I, I mean, I guess I mean getting up and walking around and stuff, but ...

    13. GL

      Yeah, I mean, I think that there are some individuals who do that. There's a, there's a, a, a chap called Robert Ekirch who has spent a great deal of time looking at medieval texts and seeing how they described sleep, and he has put forward a hypothesis that in medieval times, uh, people would have a first sleep and a second sleep. Now, I think that that theory is not universally accepted, but certainly for some individuals, getting up and walking around is, is, you know, certainly within the realms of normality. I, I think there are different sleep patterns. If you look, for example, um, at Mediterranean Europe, the siesta culture, so people sleeping for an hour or two at lunchtime but sleeping slightly less at night. So, um, there are a range of sleep patterns that sit within the spectrum of normality for human beings.

    14. SB

      Is there

  11. 21:06 – 24:36

    What's The Perfect Sleeping Habit?

    1. SB

      such a thing as a healthy sleep? As in, you know, you see these sort of different sleep behaviors and such, but is there, from a neurology standpoint or a clinical standpoint, a perfect sleep or a perfect sleeping habit, or, you know-

    2. GL

      Right. So I think the first thing to tell you is that sleep is different for everyone. We know that there are genetic factors, uh, that influence, for example, your timing of sleep, your circadian rhythm, whether or not you're a, a, a, a, a morning lark or an evening owl. There are also genetic, uh, influences over how much sleep we need. So for example, I ... there are one or two families that I've seen in my clinical career in whom every single member of that family sleeps for four hours a night and has no ill effects, and does not seem to have any long-term consequences from that. They don't feel tired. They ... There's no evidence that they're doing their physical health any harm, and there have been some genes that have been identified that define that trait. Now, it's a rare trait, and I wouldn't suggest that most people who are sleeping four hours a night think, "Oh, I must be genetically blessed," because the reality is probably somewhat different. So I think that in answer to your specific question, is there a perfect night's sleep, no, there isn't, because it depends on the nature of who you are and what your genetic inheritance is. But certainly we can say on a population basis, well, you know, sleeping somewhere between seven and eight and a half hours a night, if you look, and I stress, on a population basis, we see ill effects in terms of sleeping less than seven hours or sleeping more than eight and a half hours if you look at, for example, all-cause mortality or if you look at cardiovascular disease. Now, there are various potential explanations for that. Um, certainly if you're sleeping relatively little, um, you, uh, we can see that there are changes in terms of how your physiological system works that might give rise to things like blood pressure issues, weight gain, cardiovascular disease, stroke, those kinds of things. What's a little bit more difficult to explain is why your mortality and other, uh, ill health goes up if you're sleeping more than about eight and a half hours. And I think that that is probably a much more complicated picture, in that we know that there are certain drugs that people will be on, and when you're on drugs that's a marker that your health is not necessarily 100% already, w- h- that will make you a bit more drowsy than you normally are and will extend your sleep time. It may be that you have a sleep disorder which is causing you to sleep more. But there's an- another interesting potential explanation, in that we know that, for example, in certain diseases of the brain, there are changes to your sleep many years before, sometimes even decades before. A really good example of that is Parkinson's disease. So we know that in people with Parkinson's disease, many individuals will start acting out their dreams at night, sometimes even three decades before they then go on to develop Parkinson's disease. So is it that our sleep intrinsically changes in, as a precursor to certain conditions like Alzheimer's disease? And there is some emerging evidence now that actually a change in your sleeping patterns, either in terms of how deeply you sleep, how long you sleep, whether or not you nap during the day, that may be a, what we term a prodromal feature of Alzheimer's disease.

  12. 24:36 – 28:27

    Sleep Quantity Variance Per Person

    1. GL

    2. SB

      Do you see anything interesting happen when someone has a baby in terms of their ...I- I was wondering this the other day, 'cause I- I have a friend who's had, um, a couple of kids, and I was looking at their sleep tracker, and it seems like they have this inherent ability to survive, now that they've had kids, on, like, no sleep. I was wondering if there's some sort of evolutionary mechanism that makes parents, I don't know, require less sleep? (laughs)

    3. GL

      (laughs) Yeah, I'm not sure I can specifically answer that.

    4. SB

      Okay. (laughs)

    5. GL

      I've certainly seen a lot of people whose sleep has gone to pot after they've had-

    6. SB

      Mm-hmm.

    7. GL

      ... kids, and you know, a lot of people say that their sleep has never returned to normal after they've survived having a couple of kids. Um, but, you know, what- what you have to remember is that the brain is, uh, a remarkable organ, in that it has all of these adaptive mechanisms that enable us to cope with changes in our circumstances, changes in our environment. So if you put somebody in a sleep-deprived state, sleep also changes. So what- what the brain does is it prioritises the very deepest stages of sleep, stage three, slow-wave sleep, over other stages of sleep, and you know, w- we can see that in the sleep lab. So if somebody's very sleep-deprived before they come in, a- and we put them in the sleep lab, we see a sort of huge increase in their slow-wave sleep, which is the stage of sleep that's most associated with restoration, with healing, with feeling, uh, uh, feeling more refreshed, than other stages of sleep, like for example, REM sleep, or dreaming sleep.

    8. SB

      So the- the brain is prioritizing restoration faster than it would because the person's sleep-deprived?

    9. GL

      Absolutely, yeah.

    10. SB

      Hmm. So what is the- y- as you were saying there, you- you've seen families that just require four hours sleep, and they're apparently great. I- I- is that, is that a lot of people?

    11. GL

      No. It's a- a- as I said-

    12. SB

      Yeah.

    13. GL

      ... it's very, very rare. Very rare.

    14. SB

      'Cause I've looked at people's sleep trackers before, and I've been astonished by how little sleep they seem to require, but how active and great they seem to feel. And I've w- and I- I meant- had this the other day, 'cause one of my fellow Dragons, I- I said this to her, she requires very little sleep, but then she gets up at 5:00 AM and goes for, like, a 10-mile run. And I was like- I was looking at her sleep tracker, thinking, "You've been in bed for, like, five hours, and you are extremely more awake and energetic than I am, and you just did a 10-mile run. And I'll go in bed for seven hours, and my- it says that my, you know, stage three, stage four sleep is higher than hers, but for some reason, she's like, you know, bouncing into the room."

    15. GL

      Well, I- I think there's two explanations for that. The first is, um, maybe she is one of these genetically short sleepers-

    16. SB

      Mm-hmm.

    17. GL

      ... although, as I said, that seems rather unlikely. I think the other explanation is that we- we know that- that, you know, I talked a little bit about how genes influence our sleep, we know that there are genes that influence how resistant you are to the effects of sleep deprivation. Uh, and what I mean by that is that there are- there seem to be some individuals who don't feel, or- or who feel less sleepy than other people when they are sleep-deprived. But that may be separate from the cognitive effects of sleep deprivation. So-

    18. SB

      So she might just not feel it, but-

    19. GL

      ... she might not just feel it-

    20. SB

      Yeah.

    21. GL

      ... but she may exhibit those cognitive effects of sleep deprivation in the same way as you or- or I, for example.

    22. SB

      She's 10 years older than me, as well. Does that have...

    23. GL

      Well, I think th- that certainly we do see some reduction in sleep requirement as we get older. Um, we're also a little bit less about- less good about maintaining sleep as we get older, and that's because the brain mechanisms that stabilize sleep are becoming a little bit weaker. So- so this view that we need much less sleep as we get older is probably incorrect, although there is a- a- a slight reduction in sleep requirement.

    24. SB

      You mentioned earlier

  13. 28:27 – 31:44

    The Link Between Sleep And Weight Gain

    1. SB

      that when people don't get enough sleep, the chance of obesity and weight gain increases.

    2. GL

      Mm-hmm.

    3. SB

      How- how does that happen? What's the mechanism?

    4. GL

      So w- there are probably many mechanisms, but one of the- the ones that is best understood is that we know that when you're sleep-deprived, or indeed when your sleep is disrupted by anything else, like, for example, sleep apnea, there are changes that occur in terms of hormone levels of- of, uh, hormones that regulate our appetite and our satiety. And so even a single night of sleep deprivation can result in a dramatic increase in your calorie intake, uh, overnight. There have been some studies done, for example, in, um, nurses. So, uh, there was a study done that followed up nurses for 18 years, and they looked at their weight and how much they slept on a regular basis, and what they found is that those nurses that were sleeping less than about six hours, uh, a night on a regular basis first of all started off at the beginning of that 18-year period, uh, at a slightly higher weight, but over the course of those 16 years, uh, 18 years, they put on much more weight than other groups. So, uh, there is a very clear correlation between sleep duration, sleep quality, and weight gain. We see that, for example, in individuals who we treat with sleep apnea. So one of the treatments for sleep apnea is a mask-like device that you wear that stops your airway from closing down at night, and for some very overweight individuals, actually, when you treat their sleep apnea, they do manage to successfully lose weight, where in the past they found it absolutely impossible to do so.

    5. SB

      Okay, so if I'm under-slept, I'm more likely to eat more calories the next day.

    6. GL

      Yes.

    7. SB

      Am I also more likely to- to reach for foods that are, like, high in sugar and bad for me?

    8. GL

      Certainly some studies do suggest that. I think it's also important to say that sleep disruption, or sleep deprivation, has some fundamental effects, for example, on, um, uh, your glucose tolerance, so your insulin resistance, um, which of course is a particular issue for people with diabetes, but it affects us all. So if you're very sleep-deprived, there are changes to the way that not only your appetite or- or what you're reaching for, but also how your body processes-

    9. SB

      Uh-huh.

    10. GL

      ... the breakdown of those foodstuffs.

    11. SB

      Interesting. 'Cause I- anecdotally, I think I can- I can-... clearly say that if I've, if I'm under-slept, I'm much more likely to eat something that is high in sugar or-

    12. GL

      Well, I think we can-

    13. SB

      ... it's not good for me.

    14. GL

      ... we can all testify to that, can't we? You know, I think everybody has known that situation where they're very sleep-deprived and they think, "Oh, well, I just need a bit of chocolate," or, um-

    15. SB

      Mm-hmm.

    16. GL

      ... you know.

    17. SB

      What- what- what's going on in the brain there? Why- why is that... Is it, is it something to do with the amygdala and the prefrontal cortex, the, like, the emotional center of our brain and, uh...

    18. GL

      Yeah, I- I don't th- I don't think we know. I think it's probably to do with the reward mechanisms that underlie our- our behaviors, that, uh, there is something about sleep deprivation that alters the rewards that we're seeking. But I don't think I can give you a clear answer on that.

  14. 31:44 – 36:17

    Circadian Rhythms Explained

    1. GL

    2. SB

      You- you also talked about circadian rhythms. If I, if I was a 10-year-old, what do I need to understand about the circadian rhythm, what it is, what it does, and why it's important?

    3. GL

      So within pretty much every cell of our bodies, there is this 24-hour clock. And in fact, if you take a single cell and stick it in a Petri dish, about 40% of the genes within that cell will exhibit this sort of 24-hour cycle. And that 24-hour cycle really controls pretty much every biological system within our bodies, be it how our liver works, how our heart works, how our lungs work. There is one particular area of the brain called the suprachiasmatic nucleus that is viewed as the master clock. It's the clock that coordinates all the other clocks within our, within our bodies. And that influences, uh, not only all of these other clocks that are occurring within the cells throughout our bodies, but influences our behavior as well. So it influences, generally speaking, when we feel tired and when we want to go to bed and when we wake up, um, and also influences things like, you know, when we feel most mentally alert, when we want to eat, when we want to drink, when we feel most able to cope with work, for example. Um, now, that circadian rhythm, that circadian clock, for most people, uh, confers the sleep onset of somewhere between 10:00 PM and midnight if you're an adult, and waking up somewhere between 6:00 and 8:00 AM. Now, the timing of that body clock is governed by two things. It's governed by our genetics, so whether or not we are, um, genetically predetermined to be slightly later in terms of our body clock or slightly earlier. And we see that in families, where lots of people with, for example, will say, "Well, you know, I've always gone to bed late and woken up late, but so has my father, so has my grandfather," et cetera, et cetera. Um, but it's also influenced by what's happening in our environment. About 50% of the, uh, definers of our circadian clock are governed by what's going on around us, be that in terms of when we're exposed to light, so we know that light is a very important driver of our circadian rhythm, when we're eating, when we're exercising, when we're doing a whole range of other activities. And also, one of the markers of our circadian rhythm is the secretion of melatonin. So, there's a very small gland in the center of our brains called the pineal gland which secretes a- a- a hormone called melatonin. That hormone tends to start being secreted in most people at around six o'clock in the evening. It peaks at the time that we want to go to sleep, and then it starts dropping down a few hours before we wake up. It's almost a- a- a chemical marker of our circadian rhythm. But we also know that giving people melatonin in tablet form, for example, can influence our circadian rhythms, so there's this sort of feedback loop between our own body's secretion of melatonin and what our suprachiasmatic nucleus, our master clock, is doing. So by giving people melatonin at particular times of the day, we can shift your circadian rhythm forward or, or back.

    4. SB

      So that master clock in the brain, where is it positioned?

    5. GL

      The suprachiasmatic nucleus is in a small area of the brain called the- the hypothalamus.

    6. SB

      And is that linked to the eye?

    7. GL

      There are links from the back of the eye to the hypothalamus. So there are some cells in the back of the eye, in the retina, that are not involved in vision, not involved in conscious vision. But what they are involved with is detecting blue light in particular, which is the part of the spectrum of light that is most important in terms of regulating our circadian clock. And there are direct links between these cells, that are called retinoganglion cells, and the suprachiasmatic nucleus. So, exposure to light, to blue light in particular, is really very important in reinforcing or adjusting our circadian rhythm. Now, of course, we live in a, in a world whereby the seasons change, and the amount of light that we're exposed to changes. So, if we were on a set rhythm all the time that was immovable and un- f- uh, unadjustable, then there would be times where our circadian rhythm might not be, uh, might- might be at odds with our environment. So, there does need to be some slight adjustment of that circadian rhythm, and light is probably the most important adjuster.

    8. SB

      Blue

  15. 36:17 – 39:34

    Blue Lights

    1. SB

      light, is that the light that comes from my smartphone?

    2. GL

      Uh, so it's, uh, so blue light, obviously, the- the strongest source of blue light is sun.

    3. SB

      Yeah.

    4. GL

      Um, but yes, these kinds of devices, your smartphone, your iPad in front of you, a range of electronic devices also have blue light within them.

    5. SB

      So if, so that's why if I'm, if I'm up on my phone till 1:00 AM in the morning, staring into the screen, I'm kind of tricking that sort of optic nerve which is then impacting my master clock, and I'm- I'm telling it that it's a different time?

    6. GL

      Yeah. So- so the thinking on that has changed a little bit over- over the last few years. So, it, you know, it was said that using these devices will trigger insomnia as a r- a- a result of blue light. Actually, it- it's likely that the amount of blue light that these devices put out is probably insufficient to do that directly. But there are two effects of using your gadget until 1:00 AM. The first is, on a, on a long-term basis, if you're doing that regularly, it will...... result in an adjustment of your circadian clock and push it back, so you will want to go to bed a little bit later and wake up a little bit later. Which is fine if you're self-employed or you don't have any restrictions on your time, but most of us need to be up at a certain time in the morning. And if your circadian rhythm is delayed significantly, the net effect of that is that you're gonna end up sleep-deprived. I mean, there's also the issue of being, you know, on Twitter or being engrossed in a, in a movie on Netflix at 1:00 AM that is going to make you delay sleep anyway. So, there are those two effects.

    7. SB

      Because it's arouse- it's arousing.

    8. GL

      It's arousing, and it grips your attention.

    9. SB

      Hmm. Well, what do you make of these people, uh, me being one of them, that watch, you know, serial killer movies when we fall asleep?

    10. GL

      Well, I think that that's only an issue if it's stopping you from falling asleep.

    11. SB

      Do you, do you see... 'Cause I have this argument a lot with my partner. She, she can't understand why I, I need to watch this, like, really stimulating stuff when I fall asleep. She likes quiet, and I need to... I f- well, I tell myself I need to, like, listen to something. Do, do you see, like, variance in, in this kinda thing, and is there a better approach or...

    12. GL

      Thi- this comes down to an individualized approach to sleep, and that's why I'm always very reluctant to say, "This is the perfect night's sleep. These are the rules for sleep." You know, for example, there are some people who, uh, for whom caffeine doesn't really influence their sleep and can have a double espresso an hour before bed and still have no problems getting off to sleep. For most of us, that's not the case. Um, if you are, uh, uh, somebody who can watch something very stimulating, very scary, and then switch it off and roll over and go off to sleep, then I guess that's not a problem for you. For most people, that's probably not the best thing to be doing at night. I think that, long term, one of the issues is, with all of these kinds of, uh, activities in bed at night before you go off to sleep, is that they weaken the psychological associations between bed and sleep. And so, if you start associating bed being a place where you're mentally active, where you're engaged, then if you have an underlying predisposition to insomnia, for example, then that can sometimes set the stage for developing insomnia later on.

  16. 39:34 – 44:35

    The Main Reasons People Are Struggling With Their Sleep

    1. GL

    2. SB

      The average person that you've treated, worked with in your clinical practice, that's struggling with sleep is, at the heart of the issue, just poor sorta sleep hygiene, like you've said there.

    3. GL

      Yeah.

    4. SB

      Because I've got so many friends that say to me that they struggle with their sleep. Um, many of them have struggled with it for years. And I d- I doubt there, that there's some sort of genetic reason why this many people are struggling with sleep. So, I imagine it's just some kind of behavioral reason.

    5. GL

      So, I think that the genes that predispose to insomnia are pretty widespread, but obviously, you know, uh, in pretty much all areas of medicine, there is an interaction between genetics and environment. And certainly, poor sleep hygiene, and that's a, it's a horrible term, I hate that term, but it's the term that is most widely used and understood, can certainly put in place certain aspects of behavior that then can give rise to chronic insomnia in the long term. So, if you've got very bad chronic insomnia, then suddenly putting good sleep hygiene in place is unlikely to fix it. But it may be that that poor sleep hygiene in the first instance gave rise or at least predisposed you to developing insomnia.

    6. SB

      And what is, um, poor sleep hygiene? If I wanted to be the worst possible sleeper-

    7. GL

      Okay.

    8. SB

      ... in the world, what would I have to do?

    9. GL

      So, I think you would probably have to, uh, um, set up your home office in your bedroom.

    10. SB

      Okay.

    11. GL

      You'd have to have, um, you know, your TV on in your bedroom all the time.

    12. SB

      Okay.

    13. GL

      Uh, uh, have, be surrounded by electronic devices. Drink a lot of coffee late in the evening.

    14. SB

      Alcohol?

    15. GL

      Uh, drink s-, a little bit of alcohol. So, alcohol in the short term, of course, is, is quite sedating. It's a central nervous system depri- uh, depressant, but it does dramatically, um, worsen the quality of your sleep and, for various reasons, the direct chemical effect, the fact that you've got a full bladder, um, the fact that you're probably snoring a little bit more. So, alcohol's not a good thing. Um, you know, not having a wind-down period, so, you know, gambling on the stock market until 1:00 AM, switching your laptop and then trying to go to bed, uh, those kinds of things. So that's, you know, the quintessential very, very bad sleep hygiene.

    16. SB

      What about when I eat?

    17. GL

      So, uh, you know, eating is perhaps less important, but n- avoiding a very large carbohydrate meal, a carbohydrate-rich meal before you go to bed for two reasons. One is that we know that it can cause some fluctuations in terms of your blood sugar. And also, if you've got a bit of reflux, it can make that much worse.

    18. SB

      Okay. What about sleeping in bed with somebody else?

    19. GL

      Well, I think that for some people they f- and again, this goes back to no one rule for everybody. You know, if you've got a, a, a, a sleep trait termed sleep reactivity, which is where your sleep is very liable to your environment, then obviously sleeping next to somebody who's snoring loudly or who gets up in the middle of the night two or three times to, to, to urinate can be, can be very disruptive to your sleep. If you've got very little sleep reactivity, you may actually find it comfortable, more comfortable, to sleep with somebody in the same bed as you.

    20. SB

      I was, um, I was thinking the other day, 'cause it, where I've currently moved into, there's no blinds or curtains in my bedroom.

    21. GL

      Mm-hmm. Mm-hmm.

    22. SB

      And I was wondering if that might be a good thing. Because it at least means that, in terms of my circadian rhythm, I'm waking up at the same time every day because I'm waking up when the sun comes up.

    23. GL

      Yeah, but the sun comes up at different times, uh, uh, uh, at, uh, on different days, firstly. Um, so if you were doing that routinely, um, you might find yourself really rather sleep-deprived, um, in the summer months. Um, and also, there is some emerging evidence that exposure to light at, um, at night in your sleep is not very good for you. So, there was a very recent study that s- im- implied that light exposure at night increases your risk of diabetes. So, um-... it certainly is not good for the quality of your sleep, and the likelihood is that you won't wake up as soon as it's light. You'll wake up at- at an hour or so after it's got light, but during that hour or so, it may have had a negative impact on the quality of your sleep. So having a dark bedroom is really part of good sleep hygiene, as is having a quiet bedroom that is not too hot or too cold.

    24. SB

      What if you wear a sleep mask?

    25. GL

      Um-

    26. SB

      Does that solve it?

    27. GL

      Yes, it does. I mean, I wear a sleep mask. I think it's, you know, particularly if you don't have good blackout curtains or blinds in your bedroom, using a sleep mask, particularly in the- in the summer months, is probably very helpful indeed.

    28. SB

      Does that mean that the only light receptors we have are behind our eyes?

    29. GL

      Well, I think that there was a- there- there were some rumors, uh, on the internet that there were, um, light receptors elsewhere, but certainly, the- the only ones that we, um, know to be of significance in terms of defining our circadian rhythm are the ones in our retinas.

  17. 44:35 – 46:15

    Sleep Myths

    1. GL

    2. SB

      'Cause I- I did psychology when I was in, uh, secondary school, and I remember reading one of the psychology books, or maybe my psychology teacher told me this, I think it was Mrs. Lowney, that there were some studies where they shined a light, like underneath someone's knees-

    3. GL

      Yes.

    4. SB

      ... and people would, like, wake up when they shone the lights there.

    5. GL

      I- I think that that's been- that's been very much discounted now.

    6. SB

      It is a bit strange, though, that the only light receptor would be behind the eyes. It just feels like... I don't know. Feels like poor design, that there's only one place where we figure out if it's night or day.

    7. GL

      So- so, you know, you see that, for example, in people who've lost their sight.

    8. SB

      Right.

    9. GL

      So- so, uh, in, uh, some individuals who have lost their sight completely, then they lose the regulation of their circadian rhythm, and they develop circadian rhythm disorders, something called a- a non-24-hour rhythm disorder, whereby, um, their circadian rhythm is on a, for example, a 25-hour cycle, and so every night, they will go to bed one hour later, uh, than they did the previous night and will go right the way around the clock, you know, every month or so. Um, so, you know, that's a very good piece of evidence that actually it's those cells in the- in the retina that are of crucial importance for maintaining the stability of our circadian rhythm.

    10. SB

      I- I wrote that down. I wrote down, "In one recent study, 40% of totally blind individuals had a non-24-hour circadian rhythm," which really kind of, for me, also highlights just how important it is to, um, think about my circadian rhythm and how much impact it's having on my whole body. The- the other part you mentioned was the biological element to our circadian rhythms, which- which people refer to as chronotypes.

  18. 46:15 – 47:55

    Chronotypes

    1. SB

    2. GL

      Yes.

    3. SB

      And I'll- This idea of chronotypes, which is essentially, from my understanding, that genetically, we all have a slight sort of disposition to sleep in- at certain times-

    4. GL

      Yes.

    5. SB

      ... and to wake up at certain times.

    6. GL

      Yeah.

    7. SB

      So there's these names, right? There's like the owl, the lark, or whatever else. I think I'm an owl, but that also could just be bad habits.

    8. GL

      Yeah. So- so, you know, certainly there's that sort of genetic predisposition. There's also these environmental factors. But there's also age, in that our circadian rhythm changes a little bit as we go through different stages of life. So, you know, it's not at all uncommon for teenagers to become more evening chronotypes, and then as we get older, we tend to shift back to the morning. So that's part and parcel of our aging biology as well. So- so I think that, you know, genetics is really important, but so- but so are other factors as well.

    9. SB

      Studies in twins, um, suggest that up to 50% of our chronotype is under genetic control.

    10. GL

      Mm-hmm.

    11. SB

      So does that suggest that we are likely to have a similar chronotype to our family?

    12. GL

      We are likely to, but obviously, our environment is not going to be exactly the same as our parents, our- you know, what we do, our behaviors are not going to be, uh, um, identical to our parents or our siblings. So yes, we more frequently see that, for example, people have a evening chronotype that runs in families, um, but that doesn't mean that... You know, look, we're- we're- we're more than just the destiny of the genes that we hold.

    13. SB

      Mm-hmm.

    14. GL

      Um, obviously, our genes are really important, um, but so are other factors as well.

  19. 47:55 – 51:25

    Where To Start Fixing Sleep Problems

    1. GL

    2. SB

      If someone came to you and they said, "I'm struggling with my sleep, you know, multiple nights in a row, I haven't been able to sleep, I'm getting in bed and nothing's happening, and then I'm waking up and I'm just sat there thinking about, you know, sleeping and I'm- I feel horrific," where would you start?

    3. GL

      So I would start, I think, by trying to understand what it is that is causing their sleep issues, because a lot of the individuals that I see who have been referred in with that sort of picture assume that they've got insomnia, and they may not always have insomnia. So, uh, I think a key issue is that we are really, really poor witnesses to our own sleep, and what I mean by that is that we often. Our experience of sleep is very different to the reality of sleep. When we bring in people into the sleep laboratory, it's not at all unusual, and I will almost always ask this question when I'm going through a sleep study with one of my patients, is, "How much sleep do you think you got over the course of that night?" And it's not at all unusual for people to say to me, "Well, I think I got two or three hours' sleep." Occasionally, even, they say, "Well, I didn't sleep at all," and then you look at their brain waves, you look at the best objective marker that you've got of their sleep, and you see that they've slept seven and a half, eight hours. So obviously, what people are experiencing is really important, because ultimately, from my perspective, I want to improve people's experience of their sleep and what it is that they're- they're- they're complaining of. But it's important to understand that what they're telling you may not necessarily be the objective truth, and that's really important when it comes to insomnia, because it's not unusual for me to see individuals who...... you know, they give you a story of very clear insomnia, but actually when you look at their sleep objectively, you find that although they say they haven't slept at all, they've slept seven hours, but that seven hours has been completely disrupted by conditions like periodic limb movement disorder, which is this, these leg kicks associated with restless leg syndrome, or sleep apnea, for example. Now, sometimes it's very evident from what people tell you that actually that's not the case, that they've just got very clear insomnia. So, so that's really the starting point to try and decide whether or not you feel confident enough in your clinical evaluation of them that, that you know what the issue is without doing a sleep study, and if you think that they do need a sleep study, then that's the point at which we, we, we arrange for that. It's also trying to understand some of the factors that might be driving their sleep difficulties. So for example, was their sleep, were their sleep difficulties triggered by a life event? Did they have sleep reactivity before this insomnia started? So were they one of those individuals who could sleep anywhere at any time whatever they wanted, uh, whenever they wanted to put their head down? Or were they the kind of individual who the night before an exam, before a job interview, before a, a presentation would lose sleep? 'Cause that often is a very strong marker for developing insomnia, uh, later on in life. Uh, and then it's also about trying to understand how the rest of their health is impacted by their sleep, but also how the rest of their health impacts on sleep. So it's not at all unusual for me to see individuals who have been started on medications for other reasons that have generated sleep issues, for example.

  20. 51:25 – 58:28

    The Rise Of Sleep Trackers

    1. GL

    2. SB

      You talked about this sort of obsession with sleep.

    3. GL

      Mm-hmm.

    4. SB

      Um, and I was wondering in the case of the patient you've just described, would you encourage them to wear a sleep tracker?

    5. GL

      So th- first of all, I have to say that I'm not ideologically opposed to sleep trackers in general. I think that they are really, really good, for example, in research. Um, they're fantastic for research. It allows us to track sleep in very, very large numbers of individuals and try and work out how that correlates with whatever we're interested in. One of the major issues with sleep trackers is that the people who often use sleep trackers are individuals who already are concerned about their sleep. So if you know that you're sleeping relatively little and you wake up feeling tired, then you probably know you're not sleeping enough. You don't necessarily need a sleep tracker to tell you that. If you're one of these individuals who has insomnia, who is spending plenty of time in bed, but simply cannot get the amount of sleep that they need, um, then what a sleep tracker will do is it'll increase your concern, your anxiety around your sleep. It's a very different picture for, from for example using a step tracker. If you're sitting on the sofa and you look at your step tracker and you realize you've only done whatever it is, 5,000 steps, it's very easy to get up and go for a walk and do another 5,000 steps. If your sleep tracker is telling you you slept really badly, and you know you slept really badly and you're already worried about how badly you sleep, there's nothing that you can do on the basis of the information that your sleep tracker is giving you to suddenly go and get a little bit more sleep. And it's complicated by the fact that, you know, sleep trackers are pretty good at telling you how much time you spent in bed. They're reasonably good at telling you how quickly you dropped off to sleep. The reliability, the accuracy of these devices, most of these devices, drops off significantly when it comes to, for example, defining nighttime awakenings, defining stages of sleep, those kinds of things. So then you have that additional issue in the mix which is that sometimes that your sleep tracker may be giving you information that is not factually correct, and that may increase your anxiety further. So I'm really very, very keen for people who have issues with their sleep, rather than just burning the candle at both ends, to put away their sleep tracker and actually go and have a chat with their GP or somebody who knows a little bit about sleep rather than relying on this sleep tracking technology.

    6. SB

      Do you think sleep trackers have had a net negative or positive impact on sleep culture?

    7. GL

      I think that for those individuals who can fix their sleep in a very straightforward way by spending more time in bed, so the kind of people that I talked about that 20 years ago would be saying, "Well, you know, I only sleep five hours and, you know, 'cause I'm busy doing X, Y, and Zed and I can get away with it," I think it's probably encouraged them to spend a bit more time in bed 'cause they know they have a, a very clear, um, very clear bit of information that's telling them they're, they're not sleeping enough. But for the people that I see, the people who are already concerned about their sleep, uh, and who have difficulties with their sleep, I think it's been a very negative impact. Um, and I have some reservations about, well, people like myself, um, sitting on these kinds of podcasts or writing in newspapers telling you, "Well, you know, if you don't get enough sleep, you're gonna die early, you're gonna have all these negative health consequences," because for a subgroup of individuals who are already very concerned about their sleep that actually can-

    8. SB

      Make it worse.

    9. GL

      ... cause problems. And I have seen individuals who, for example, have read books on sleep and how important it is on sleep who have ended up going into a spiral of insomnia and very catastrophic depression and anxiety as a result. So, so it's very, you know, it's very important to be clear that the, all of this is a double-edged sword.

    10. SB

      It's interesting with, with sleep trackers. Um, I can see... I think it's worth me saying that I am both an investor in Whoop and I'm also sponsored by Whoop.

    11. GL

      Okay.

    12. SB

      But I also agree with the things you've said. So I've seen this, this sort of variance in how a sleep tracker can...... improve some people's lives, and it can make other people more anxious in a way that's not helpful. So, for me, my sort of testimony on it is, um, I was one of those people you described earlier that thought sleep was take-it-or-leave-it. And when I started seeing a sleep tracker, it's kind of like the, when I saw my brain for the first time. I did a brain scan, and I didn't even kind of like realize it was there, and that I could influence it, and that things I was doing-

    13. GL

      Mm-hmm.

    14. SB

      ... um, without really thinking much were having this big impact. And for me, what it did is it allowed me to finally make this link between how much sleep I've had and then how I behave. Now, I thought my behavior was random before.

    15. GL

      Mm-hmm.

    16. SB

      But seeing that when, when my sleep, um, scores were down, I was way more emotional, I was way more likely to eat crap. Uh, and the other thing that I saw which was really interesting was that when I had a glass of wine, or two glasses of wine or three glasses of wine, that it just like, uh, destroyed my sleep, and I never knew that before, and I was in search of reasons to quit alcohol anyway, and when I saw that, I quit alcohol forever. So, I've not drunk since. So, and then for me, I have to also say, there are moments in my life where life happens and I know I'm not gonna sleep, and I don't pay attention to my sleep tracker. But there are other moments where I have a bit more control, and that's when I kind of tune in to my sleep tracker. I've also had parents message me a lot and say, "Listen, I've got a one-year-old, a two-year-old, a three-year-old, whatever. There's no point in me wearing a sleep tracker, 'cause listen, I'm not gonna get any sleep." And I also completely, uh, agree with them, that there's really no point in that situation. I think there's a point when there's something you can do about it.

    17. GL

      Yeah.

    18. SB

      And that's kind of what you're saying.

    19. GL

      That- that- that's absolutely key.

    20. SB

      Yeah.

    21. GL

      So- so the- the- the- the point of doing anything like that is if there are very clear things that you can do on your own to close that loop. There's no point in having information without being able to act upon it.

    22. SB

      Yeah.

    23. GL

      And I guess if you are one of those individuals like yourself, who very clearly can correlate certain things that they're doing in their daytime lives with their sleep and, and, and how they feel subsequently, then, then great.

    24. SB

      Mm-hmm.

    25. GL

      You know, I guess I have a little bit of bias, in that the people that I see are already struggling with their sleep already.

    26. SB

      Yeah.

    27. GL

      And so it goes back... I- I guess we're completely in agreement.

    28. SB

      Yeah, yeah. We are, yeah. And it's so interesting, 'cause I, that's been a developing idea, 'cause obviously my bias is always like, "Wouldn't you rather know?"

    29. GL

      Mm-hmm.

    30. SB

      'Cause that's, you know... But then, h- h- from doing this podcast, I've, I've seen the comments and I've seen the struggle, and from speaking to parents that are struggling with their sleep, and it's kinda, sometimes just makes them feel worse about it. Um, I think nuance is necessary on this issue. Um, and I'm sure there's a lot of, a lot of things in my life that I wouldn't like to tr- be able to track because either I f- I don't have control of them right now, or, you know, um, maybe they'd make me feel more anxious. There's

  21. 58:28 – 1:01:50

    What Is The Glymphatic System?

    1. SB

      this thing called the glymphatic system, which I find really-

    2. GL

      Yeah.

    3. SB

      ... which, when I discovered this, I, I, it really helped me to understand the importance of sleep. Can you explain what the glymphatic system is as if I was a 10-year-old?

    4. GL

      Yeah. So, um, within our bodies, there is a, a system, a very similar system called the lymphatic system. So, people will have heard of lymph nodes, for example. And this is a system whereby fluid that comes out of the blood vessels and into the tissues is then collected and transported back into the, the cardiovascular system. And we used to think that n- there was no equiva- equivalent system in the brain, but actually, you know, over the last 20 years, we've understood that whilst there are no sort of lymph nodes or things like that, there are these very small channels between the cells that are responsible for draining fluid from the brain, and, um, those, um, systems are responsible for removing certain toxins or metabolites, chemicals that have built up as a result of metabolic activity within the brain and removing them from the brain substance itself. Now-

    5. SB

      So, it's like a carwash.

    6. GL

      Um, y- like, like a drainage system. You know-

    7. SB

      Okay.

    8. GL

      ... like a, like, like a gutter, for example-

    9. SB

      Okay.

    10. GL

      ... um, you know, that takes the suds from the car wash away and puts them into the drain. Um, in about 2011, if my memory serves me correct, there were some studies done that looked at that glymphatic system in different stages of sleep. And what they described was that that glymphatic system opens up significantly, by about 60%, i- in very deep sleep, in the deepest stages of sleep. And so, and so subsequent research showed that, for example, one of the proteins that was being r- removed was a protein called beta-amyloid that is res- that is intimately tied to Alzheimer's disease. And so, the view that deep sleep was particularly respon- uh, responsible for housekeeping of the brain, for chemical housekeeping of the brain, came about. And it gets a bit more complicated, because actually only two or three weeks ago, another study suggested that that 60% increase in the glymphatic system was not the case. And so, I think that this remains an area that there is some uncertainty about. But actually, there are many reasons to tie in sleep in general, separate from the glymphatic system, into a general housekeeping role of the brain. And I think that, um, certainly this is an area that is gonna keep researchers very, very busy over the next 10 or 20 years, this, uh, association between sleep cognition and cognitive decline in later life.

    11. SB

      That, that protein that seems to s- spike if we are sleep-deprived-

    12. GL

      Mm-hmm.

    13. SB

      ... beta-amyloid?

    14. GL

      Beta-amyloid, yeah.

    15. SB

      And that's linked to Alzheimer's?

    16. GL

      It is, yeah. So, in Alzheimer's disease we see beta-amyloid deposition within the brain substance itself.

    17. SB

      What does deposition mean?

    18. GL

      So, uh, it's deposited within the brain.

    19. SB

      Okay. S- if someone has Alzheimer's, they have a, a sort of the build, b- a buildup of beta...

    20. GL

      A b- buildup of beta-amyloid in-... the, the brain substance.

  22. 1:01:50 – 1:02:54

    The Link Between Sleep Deprivation And Alzheimer's

    1. GL

    2. SB

      Is there a link between sleep deprivation and Alzheimer's? Do we see high numbers?

    3. GL

      So, there is some evidence to suggest that, uh, both chronic sleep deprivation and insomnia are associated with cognitive decline and conditions like dementia. It goes back to what I was saying earlier, which is... But by the way, there's also some studies that have suggested links between sleeping tablets and conditions like Alzheimer's. So, it goes back to this issue of whether or not it's, uh, the insomnia or the sleep deprivation that causes Alzheimer's. Is it sleeping tablets that causes Alzheimer's, or is it the fact that Alzheimer's many, many years before causes changes to our sleep? Uh, and so I think that that story has not yet been, um, has not yet come to fruition in terms of our fundamental understanding of the links between sleep and Alzheimer's disease, and whether or not it's directly causative.

  23. 1:02:54 – 1:04:38

    Medicating To Help Sleep

    1. SB

      Do you recommend/are you a fan of... You just referenced sleep tablets there, sleep medicine, medication.

    2. GL

      Yeah. So as a general rule, no, because I think that there are, um, good now non-drug based techniques for trying to improve sleep in the majority of people with insomnia. Um, there is some evidence that, for example, if people don't respond to these non-drug based methods, giving them sleeping tablets alongside these non-drug based methods makes it more likely for the psychological route to help. But, you know, unfortunately, as part of my clinical practice, I see lots of people who've been struggling when they're asleep for many, many years, and they've tried all non-drug based treatments, and the risks of them sleeping so little in terms of their mood, their anxiety, their ability to function, uh, uh, are so great that actually you have on a case by case basis to make a judgment call as to whether or not to say, "Well, I give up on your sleep." Or actually you say, "Well, look, there are a number of drugs that we can try to try and improve your sleep, and it's not going to get you back to normal, but it's going to potentially make the difference between you, you know, end up very depressed or, or, or, or highly anxious and unable to cope in your life or actually get some decent sleep," um, and the risks of those drugs. And that needs to be judged on a case by case basis, and it's part of clinical medicine. Whenever we prescribe any medication for anybody for any condition, we have to evaluate what the potential benefits are versus the potential

  24. 1:04:38 – 1:06:05

    Side Effects Of Melatonin

    1. GL

      risks.

    2. SB

      A lot of people seem to be taking melatonin-

    3. GL

      Yeah.

    4. SB

      ... tablets. Is th- is that healthy? Is that free from side effects?

    5. GL

      So, it's not entirely free of side effects, um, but it's generally a pretty well tolerated, safe drug as far as we know. There are some specific issues surrounding melatonin. Um, but a question really would have to be, well, why are you taking that melatonin? Is there something that you can do to fix your sleep without rely- relying on an exogenous substance, something that you've bought off the shelf or been prescribed?

    6. SB

      Is, is there... H- hesitation and reservation with taking things like melatonin is always that I just assume that my body will become a little bit reliant on it.

    7. GL

      Yeah. Well, I think-

    8. SB

      Is that a fair assumption?

    9. GL

      ... I, I, I think whether it become, whether you become physiologically, biologically reliant upon it or psychologically reliant upon it, it, it, it remains unanswered. But certainly, the, you know, there are individuals who, for example, will say, "Well, as long as I know that I've got a bottle of melatonin or, you know, the sleeping tablets in my bedside cabinet, I sleep fine. As soon as I know that I haven't got access to them, I don't sleep very well at all." And so that, I think, exhibits that this is almost like a psychological crutch, knowing something that they've got s- uh, n- next to their bed that they can reach for in order to achieve a good night's sleep is sometimes as import-... Is as important as the biological effects of taking that tablet.

  25. 1:06:05 – 1:14:38

    Non-Medical Alternatives To Help Sleep

    1. GL

    2. SB

      I mean, that kind of leads to the non-medical techniques to improve our sleep.

    3. GL

      Mm-hmm.

    4. SB

      So, you said typically with, with someone that comes to your sort of sleep center, instead of going straight to medication as the answer to their sleep issues, you would suggest and/or try non-medical interventions.

    5. GL

      Yes.

    6. SB

      And you said that these work well.

    7. GL

      Yes.

    8. SB

      What are these non-medical interventions?

    9. GL

      So, so the gold standard treatment now for insomnia is a treatment called cognitive behavioral therapy for insomnia. Okay. So, a lot of people have heard of CBT because they will have heard of it in the context of depression and treatment of depression or anxiety. Now, CBT for insomnia is not actually directly related to the CBT that's used for depression and anxiety. It borrows from the principles of CBT and applies them to sleep, and it serves two purposes. The first is to try and address some of those conscious psychological factors that are driving insomnia. And when I talk about conscious factors, I'm talking about things like the frustration or anxiety of the night ahead, of lying in bed at night feeling that you can't get off to sleep, and the frustration and anxiety that that engenders of having your partner snoring away in bed next to you whilst you're struggling to go off to sleep, of worrying about how you're going to be able to function the following day, or potentially even the long-term effects of your insomnia. So, those are the conscious psychologic factors, and CBT-I aims to address those, but it also aims to restore normal, um, unconscious factors that give rise to good sleep. So, if you've spent a great deal of time in bed at night awake, then those normal associations that good sleepers have between bed and sleep... So, for a good sleeper-... they will associate bed with being a place of comfort, with being a calming, relaxing place, a place that they associate with a good night's sleep. If your sleep has been disrupted for a period of time, and you've spent long periods of time in bed awake, then that positive association between bed and sleep is replaced by a negative association. So you- you begin on an unconscious basis, Pavlovian conditioning it's called, um, you associate that bed environment with being awake, with being wired, and that's often what gives rise to the sensation of having lost the switch to be able to get off to sleep. In fact, some people with insomnia will say, "Well, look, you know, if I'm sitting in front of the television, and I'm sitting on the sofa, and I'm not thinking about sleep at all, I'm not thinking about bed, I will often find that I've dozed off. And then I'll go upstairs, get into bed, and as soon as my head hits the pillow, ping, I'm wide awake and I suddenly feel wired." So that's very illustrative of that sort of unconscious association between bed and being awake rather than being asleep. And so CBTR aims to address that as well.

    10. SB

      How does it- how does it do that?

    11. GL

      So it uses a variety of different techniques. So it uses some standard sort of relaxation techniques to try and reduce th- the level of vigilance, of physiological- of mental arousal that you have when you get off to bed. But also, it aims to utilize a- a- a variety of techniques to reprogram your brain to associate bed with sleep. So one of the ways in which you can do that is you can actually utilize your brain's own mechanisms, um, that drive you to go off to sleep. So that's something called the homeostatic mechanism, which we'll all be very familiar with, but not in those terms. So the more you've been awake, the stronger the chemical drive for your brain to go off to sleep. So, one of the features of CBT-I is to compress your sleep or to restrict your sleep for a period of time. E- essentially what that means is, well, if you are an in- somebody with insomnia, and you estimate, for example, that you're only sleeping a total of six hours a night in bed, um, but you're spending eight hours a night in bed, then you, for a period of time, you say, "Well, look, I want you to get into bed at midnight, and whatever happens, I want you to get out of bed at 6:00 AM." So to restrict the time in bed to six hours. So, the first few nights, most people with insomnia will sleep really badly because they know that their alarm is going off at 6:00 and they know they have to get off- get out of bed at 6:00. But after a- a little while, they become so sleep deprived that the brain starts forcing you to go off to sleep much more quickly, and over time, more and more of that six hours a night will be spent asleep in bed. And that's the first step in breaking that negative association between bed and wake, and rebuilding a positive association between bed and sleep. I mean, at its extreme, there is a technique that was developed in Australia which is called Intensive Sleep Retraining, and in that technique, people who've got very bad insomnia are brought into a sleep laboratory having been awake for the night before they come in. So they come in in the evening having been awake for now probably 36 hours. Every half an hour, they're given the opportunity to drop off to sleep. They have some wires on their heads, their brainwaves are being tracked, um, but as soon as they've been asleep for three minutes, based on their brainwaves, they're woken up again. And that happens every half hour for 25 hours. So over the course of that 25-hour period, they have 50 opportunities to nap. Now, for most people with insomnia, having been awake- even having been awake the previous twen- uh, 36 hours, they will still not be able to get off to sleep for the first few naps. But as they get more and more sleep deprived, every time they're given the opportunity to drop off to sleep, they will start falling asleep more quickly.

    12. SB

      Hm.

    13. GL

      And at the end of that 50 naps, they will be dropping off to sleep very quickly, as soon as the lights go off. Um, and actually, the evidence suggests that that's a very good, um, short-term treatment for chronic insomnia, and in- in some individuals, it works extremely well in reassociating your head hitting the pillow with drifting off to sleep. I wouldn't suggest it for most people 'cause it's basically a form of torture, but I think it illustrates the power of trying to get people into a more sleep-deprived state if they've got insomnia.

    14. SB

      It's interesting 'cause much of what you've said makes me think that we- we all have our own sleep identity. And when I say sleep identity, I mean a story we tell ourselves about our relationship with sleep, and it makes me think that our sleep identity is much more powerful than I think we think. 'Cause if you speak to anybody, anybody in this room, upstairs, wherever, and you say, "What are you like at sleeping?" they will deliver their sleep identity. They'll say, "I'm a bad sleeper." And I wonder how much of that is self-fulfilling. 'Cause I- I think I've always told myself that I'm a good sleeper, and therefore, I find sleep easy. Um, and I've got friends who will say, "Oh, I'm a really bad sleeper," and I'm wondering how much that's impacting their ability to sleep and/or if they're- they even know objectively if they are actually a good or bad sleeper, it's just this identity we've embodied. Do you- do you see that a lot? Do you see that how- someone's sleep identity kind of determines how they actually sleep?

    15. GL

      I think all of that is true, undoubtedly. Uh, and I think this comes back to the earlier bit of our conversation about sleep trackers, because obviously, sleep trackers reinforce that sleep identity-

    16. SB

      Mm-hmm.

    17. GL

      ... whether- whether they are 100% accurate or not. Um, and so yes, that would- that sort of sleep identity would undoubtedly influence both those conscious and unconscious factors that give rise to sleep.

    18. SB

      Mm-hmm.

    19. GL

      You know, if you're a good sleeper and you've always been a good sleeper, you don't worry about any of these things. You probably don't even worry about any aspects of sleep hygiene or quite happily, you know, l- l- like you, watch a horror movie in- in- in- in bed before you drift off to sleep. But for those individuals who are- who are not, um, yes, absolutely that- that- the way that you view sleep and your relationship with sleep is of fundamental importance. It is...... again, coming back to genes, we know that there are undoubtedly genetic factors that influence whether or not you're likely to develop insomnia. So, again, as with all aspects of sleep, it's that combination of genetics, environment, and when I talk about environment, I'm also talking about your own psychological, internal environment.

    20. SB

      I, um, the other

  26. 1:14:38 – 1:17:49

    Surgery To Fix Sleeping Issues

    1. SB

      thing I was thinking of, we talked about sleep apnea earlier on, but it seems that a lot of people believe they have a deviated septum. Is it called deviated septum?

    2. GL

      Uh, septum, yeah.

    3. SB

      Septum.

    4. GL

      Yeah.

    5. SB

      Septum. I've heard some people say that that's the reason that they can't sleep, and they've gone off to get surgery to kind of correct the deviated septum.

    6. GL

      Mm-hmm.

    7. SB

      What's your thoughts on that? Is that, is that true? Because I wonder how, I'm like, d- you, "We can't all be b- being born broken with these deviated septums or whatever."

    8. GL

      I think it's normal for us to have some asymmetry in our noses.

    9. SB

      Mm-hmm.

    10. GL

      And a lot of people have a deviated septrum, septum as a result of having broken their nose, for example. Um, y- you know, I'm a little bit suspicious about, you know, operations for that kind of thing, unless there are very clear abnormalities that might be responsible for sleeping poorly. So one of the major issues, for example, in sleep apnea is, s- s- sleep apnea, the obstruction is in the throat, it's not in the nose.

    11. SB

      Mm-hmm.

    12. GL

      And so, uh, issues with nasal congestion or difficulty breathing through the nose do not directly cause obstructive sleep apnea. What they can do in some individuals is they can encourage them to, people to breathe through their mouth and breathe with their mouths open, which alters the position of the jaw and can create a bit more narrowing in the back of the throat. So for some individuals who have very prominent nasal congestion at night, and who have evidence of sleep apnea, sorting out their nasal congestion and correcting a deviated septum may be one way of doing that. There is undoubtedly a rationale for sorting that out. Uh, I think that there are probably quite a few individuals who are having unnecessary operations.

    13. SB

      Makes sense. I am... So we've got the cognitive behavioral therapy for insomnia as one cure. We've got that extreme torch therapy that they did in Australia.

    14. GL

      Yeah.

    15. SB

      We've got melatonin. Um, magnesium? People have mentioned magnesium to me before.

    16. GL

      Yeah, so, so anecdotally, magnesium can help some individuals. Um, and, you know, anecdotally also, magnesium is a very g- good treatment, as testified to by some of my patients, for conditions like restless leg syndrome. So-

    17. SB

      What's that?

    18. GL

      ... restless leg syndrome is this sort of neurological disorder whereby people, um, and it's often associated with things like pregnancy or low iron levels, but it's under genetic control as well, people ex- uh, experience, uh, uh, a number of different things. So the first thing is that they get an urge to move at night, um, and it's typically at night rather than during the day, often associated with unpleasant sensations, that if they try and keep still, that sensation builds and builds and builds until they have to move, that if they do move, they get some transient relief, and it's often associated with kicking at night in your sleep. Um, it's very common, very common in pregnancy, um, very common in people who are anemic, f- and i- in people who've got problems with their kidneys, but it's common in the general population as well. And so, uh, for people with restless leg syndrome, magnesium does sometimes help significantly.

    19. SB

      And

  27. 1:17:49 – 1:19:40

    What Would Brain Scans Reveal About Sleep Deprivation

    1. SB

      it, what's it doing? It's relaxing or something?

    2. GL

      I don't, I don't think we actually know-

    3. SB

      Oh, okay.

    4. GL

      ... precisely what it's doing.

    5. SB

      Okay. Um, when you look at an under-slept brain-

    6. GL

      Hmm.

    7. SB

      ... so if I were sleep-deprived, what, what would the difference in my regular sleep activity be? What would you see? Would you see my brain as, like, not active? Would you see part of it not, not active?

    8. GL

      So, we would see, on a gross level, on a sort of macro level, we would see that your brain is prioritizing very deep sleep over, um, other stages of sleep at night. On, during the day, if you're chronically sleep-deprived, using the techniques that we use in clinical practice, you would see very little. There is some increasing evidence that actually what is happening within our brains is that we are constantly showing little areas of our cerebral cortex, the outer lining of our brain, the bit of the brain that's responsible for our cognitive abilities, for example, that dip in and out of electrical silence, what has been termed local sleep. So that there are little islands of local sleep that are constantly occurring over our cerebral cortex whilst we're awake. And as we get more and more sleep-deprived, and you know, depending on how much we've used that particular bit of our brain, those islands tend to get slightly, um, longer, th- the periods of silence get longer, and those islands become more widespread. So, we're constantly, even if you and I are, are talking, there are little areas of the brain that are constantly dipping in and out of sleep. But if we're very sleep-deprived, actually that, uh, electrical silence of our cerebral cortex gets more extensive and more widespread, which is probably why, or at least one of the reasons why, we decline from a cognitive perspective when we are very sleep-deprived.

  28. 1:19:40 – 1:21:11

    Sleep Deprivation Affects Your Mood

    1. GL

    2. SB

      Ah, okay. So my... Okay, interesting. 'Cause, okay, so different little parts of my brain are doing little micro sleeps if I'm sleep-deprived.

    3. GL

      Yes.

    4. SB

      And that, from a behavioral standpoint, will show up in my day-to-day life as worse cognitive performance, maybe less focus. Um, are there... 'Cause I've always, I've always wondered why, on an under-slept day, I feel like I'm more emotional. You know, people say, y- they attest to the fact that if someone's a little bit cranky, they think, "Oh, they probably have not slept last night."

    5. GL

      Yeah.

    6. SB

      Or, th- there's that phrase, isn't there? Like, who woke up on the wrong side of the bed and-

    7. GL

      Yeah.

    8. SB

      ... et cetera. Is, is there a scientific basis for that?

    9. GL

      So, I don't think we f- can fully explain it. I think that there are... Certainly the areas of the brain that are responsible for, for, for emotion and emotional cognition are more metabolically active, and so may be more vulnerable to the effects of sleep deprivation. I think, um, uh, we... It is likely that when you're sleep-deprived, there are some changes in terms of certain neurotransmitters within the brain that may, uh, exacerbate that. Um, but what is very, very clear is that that association between sleep...... mood, anxiety levels is very, very clear. And in fact, we see that, for example, in people with clinically significant anxiety or clinically significant depression, that actually treating anxiety or depression in somebody who is sleep-deprived or has insomnia is much more difficult, that treating the insomnia in somebody who is anxious or depressed is much more difficult without addressing the anxiety and depression. And

  29. 1:21:11 – 1:22:47

    Can Parts Of Our Brain Be Asleep?

    1. GL

      so this is, you know, this is really significant, not just on a day-to-day basis for all of us, but also in, in clinical medicine and clinical psychiatry.

    2. SB

      S- so, uh, j- jumping back to the point about when we're under-slept, certain parts of our brain are doing little micro sleeps-

    3. GL

      Mm.

    4. SB

      ... it is fair to say that the phrase that, you know, we're half-asleep-

    5. GL

      Mm.

    6. SB

      ... there's some merit to that?

    7. GL

      Yeah. We may not be half-asleep, but we could be a thousandth of asleep or a hundredth asleep. And, you know, th- this, this idea that the brain can exist in different stages of sleep or wake at the same time, by the way, also extends to, to the nighttime. So for example, in people who sleepwalk, who do really rather dramatic things, and, you know, I've had, I've seen patients, for example, who've driven in their sleep. One patient who rode a motorbike in her sleep. I've seen, uh, people do some incredibly complicated things, like cooking a meal in their sleep. All of these sleepwalking-type events relate to the fact that certain parts of the brain are in very deep sleep, whereas other parts of the brain actually demonstrate waking activity. So, the bits of the brain that are s- remain asleep are the frontal lobes, which are, you know, basically where our rational thinking, where our decision-making occurs, and the parts of the brain that are responsible for memory, uh, a part of the brain called the hippocampus. Whereas, actually in these events, there are s- other areas of the brain, like the areas responsible for movement or for vision or emotion, uh, demonstrate waking activity both on an electrical basis but also on a metabolic basis as well.

  30. 1:22:47 – 1:25:08

    Dreaming

    1. GL

    2. SB

      Why do we dream? It's a big question, isn't it?

Episode duration: 1:58:55

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