Bản chép lời đầy đủ của Solving Sleep

that you sort of put something on to listen to because I like listening to audiobooks and that often puts me to sleep. 00:02:42 Professor Russell Foster: One of my favorites is In Our Time, as I mentioned, but also that wonderful series Lord Peter Wimsey. That's very wonderful and non- threatening. 00:02:51 Krutika Adatia: Brilliant. For me it's Harry Potter because I've read the books and I've watched the movies, so it's familiar and it'll just... 00:02:56 Professor Russell Foster: I think that's a good point because it is familiarity with something that's non- threatening and gentle. 00:03:01 Krutika Adatia: Why is it that we need sleep? 00:03:04 Professor Russell Foster: Well, of course, for so long, sleep was disregarded as sort of an indulgence and a luxury and almost as an illness that needs a cure. And what's emerged over the past 20 years or so is that sleep is an absolutely essential part of our biology. The quality of our waking day is defined more or less by the quality of the sleep that we get. So it's an essential part of our biology and I think so many of us marginalize it. Sleep is always the first victim in squeezing more and more and more in to an over packed day. So we need to embrace it and not treat it as some sort of luxury. 00:03:43 Krutika Adatia: I'm glad you've mentioned that because I'm just thinking about our listeners who might be students and cramming or potentially working late into the night and often sacrificing their sleep, what we're saying is that that shouldn't be the case. 00:03:57 Professor Russell Foster: Absolutely. If we think about some of the things going on within the brain whilst we sleep and what's emerged again fairly recently is that sleep is a time when we consolidate our memory. All that information is rushing in during the day and we don't have time to process it effectively. And so whilst we sleep, we can consolidate memory. But the other thing, it's not just the retention of facts. There's a wonderful study from Germany which looked at the solving of problems. So this experiment was quite a complicated task. It was introduced to individuals in the morning, so they became familiar with the task and one group performed it that afternoon and only 20% of the group actually solved the problem. The next group introduced in the morning, familiarized with the task, performed it the following afternoon, but they were deprived of sleep. Again, about 20% of the group solved the problem. But the really interesting group, of course is introduced in the morning, performed at the following afternoon,

but with a full night of sleep, 60 to 70% of the group solved the problem. It's a brilliant example of how we're processing information. We're coming up with novel solutions to complex problems, and that's just one reason why students or all of us need to take our sleep very seriously. 00:05:15 Krutika Adatia: So we need that sleep to help with the consolidation, the sort of memory form, which is obviously important for learning. 00:05:19 Professor Russell Foster: And the answering of questions. So it's not just the retention of facts, it's the processing, it's the manipulation of that information, which I think is so amazing. 00:05:29 Krutika Adatia: That is incredible. I mean, this is probably a question that's sort of how long is a piece of string, but how many hours of sleep does an average person need? 00:05:39 Professor Russell Foster: Well, that's a really good question and it's part of the reason I wrote this book called Lifetime because I was fed up with the sergeant majors of sleep screaming, " You must get eight hours." The healthy range according to the National Sleep Foundation is between six hours and some people may need up to 11 hours and it's all about defining what you need and then defending your sleep. And so that's the key thing. Seven to eight hours is an average, but it would be wrong to impose an average value on everybody. It's like shoe size. You wouldn't dream of making everybody wear the same shoe size and we shouldn't dream of making everybody's sleep or expecting them to sleep exactly the same length. And the key thing is defining if you're tired or not and how much sleep do you need? Well, if are feeling that you are not firing all cylinders during the day, if you don't feel as though your brain isn't working accurately and precisely, that's a good indication you're not getting the sleep at night. If you oversleep on free days at the weekend, for example, if you need an alarm clock to drag you out of bed or somebody else, if you're craving caffeinated drinks to wake you up, if you're feeling sluggish during the day. And importantly if you or your friends and family note behavioral changes. You're more irritable, you're less empathetic, you're failing to pick up those sorts of signals from friends and family and you're doing stupid and unreflective things. This is all telling you you're not getting the sleep you need and you need to take a refresh and think, " Right, I'm going to go to bed a bit earlier and get a bit longer sleep." 00:07:17 Krutika Adatia: So I guess you're alluding to this in

your answer that you've just given, but figuring out how many hours of sleep you need is just being a bit more self- aware. 00:07:27 Professor Russell Foster: Absolutely, yes. And as I said, we think we don't really need sleep, so we work way into the night and I certainly did as a student, but I don't think it did me any good because I didn't get that consolidation of memory and processing of information. 00:07:42 Krutika Adatia: And so are we saying that maybe we might not always need the same amount of sleep every day as well? Could it vary? 00:07:49 Professor Russell Foster: Sleep is a very dynamic part of our biology. It changes as we age and due to external circumstances, we may not get the same sleep every night, but essentially it's trying to get the best sleep we can. 00:08:01 Krutika Adatia: Now just moving on to another topic here, which I know you also have a specialism in, and that's circadian rhythm. Can you tell us what exactly is the circadian rhythm? 00:08:12 Professor Russell Foster: If we step back and think about, well, what's our biology? What does it do? Well, ideally it delivers the right stuff at the right concentration to the right tissues and organs at the right time of day. And this circadian rhythm's internal biological clock provides the time structure to allow us to do the right stuff at the right time. And fine tune our physiology and behavior to the very demands of the rest activity, the sleep wake cycle, which of course has evolved as a result of sitting on a planet that revolves once every 24 hours. And so it's providing this essential time structure for life. So in anticipation of going to bed, we see that core body temperature drops, we see other factors, hormonal changes occur, and then in anticipation of waking up in the morning before we've even woken up, core body temperature rises, metabolic rate increases, and we're mobilizing glucose and hormones underpinning energy so that when we do wake up, we can exploit that new environment, the dawn to our best of abilities. So it's this wonderful device to anticipate predictable change within the environment and allowing us to function optimally. 00:09:25 Krutika Adatia: Right. And so are we saying everyone has the same kind of biological body clock or does it vary from individual to individual? 00:09:33 Professor Russell Foster: It certainly varies, and that brings us really to the subject of chronotype. And that sort of crudely means whether you're a morning person, a lark, an intermediate dove, or a late person, an owl. And there are three factors that

contribute to this. One is your genes. So we know that there are subtle changes, very small changes in some of the clock genes which underpin our circadian rhythms. And they can make you get up earlier or make you get up late. And so by essentially their contribution to our genes, our parents are still telling us what time to go to bed and get up. So there's that element which is to some extent fixed. The other thing that changes is how old we are. So from about the age of 10, there's a tendency to want to go to bed later and later and later peaking in the late teens, early twenties. So there's a sharp rise in wanting to go to bed later. And then there's a slow return as you age to want to go to bed earlier. So by the time you're in your late fifties, sixties, you're getting up and going to bed at about the time you got up and went to bed when you were 10, 11. But the key thing is that somebody in their fifties, sixties will want to go to bed on average two hours earlier than when they were going to bed in their late teens and twenties. And that sharp rise and slow move to a more morning chronotype is due to the hormonal changes associated with puberty. So we've got genes, we've got the sex hormones. And the third thing, which is the thing we have some control over and is often overlooked is when we see light. So morning light advances the biological clock, makes us get up earlier and go to bed earlier. Evening light, dusk light delays the clock, we want to go to bed later and get up later. We did some studies actually on university students a few years ago all over the world, and we found that the more owl- like they were, they were missing the morning light, which will get them up earlier, but they were getting lots of late afternoon evening light, which would push the clock later. And so it's a key point because if you're a late type, you can set the alarm, either sit in front of a light box. If it's sunny outside, go outside 30 minutes and you can sort of nudge clock forward in time. So there's three things, genes, age, development, and when you see light. 00:12:00 Krutika Adatia: What happens then to our sleep when students are stressed or anxious? 00:12:06 Professor Russell Foster: Well, this is the great enemy of sleep. Most people don't have a sleep problem at all. It's dealing with anxiety and stress and that can delay sleep onset. Or if you wake up, it'll be very difficult to get back to sleep again. And so what you need to do is devise strategies that de- stress. First of

all, embrace sleep and enjoy the sleep that you get. Recognising that your sleep pattern may be different from your partner or whoever you share your life with. And we're going back to defining how much sleep that you need. And so at the end of the day, you need to wind down. That may be relaxation therapy, for example. It may be exercise. Don't exercise too close to bedtime because that can raise core body temperature and that can actually delay you getting to sleep. That's one of the interesting things about sleep initiation. That's a drop in core body temperature. The other thing I recommend is not talking about stressful subjects. It's often the only time of the day when you and a partner can actually talk about the stuff that needs to talk about, but it's actually sometimes rather stressful. And so I've certainly banned in our house any mention of family finances while we're lying in bed at the end of the day. 00:13:21 Krutika Adatia: That's a good idea. 00:13:22 Professor Russell Foster: Just find a time but don't have it before you go to sleep. So it is all about finding those techniques that allow you to relax and wind down. Many people use mindfulness, it doesn't work for everybody, but many people have found that. Also, a relaxing bath for example. It's experimenting and finding out what works for you. There will be a solution. I think many people feel that sleep is what you get, but actually as we've touched on, it's a very dynamic behavior and we do have a lot of control over it. And it's coming to terms with anxiety and stress will absolutely improve your sleep. 00:13:56 Krutika Adatia: And I like the point that you've mentioned about avoiding stressful conversations, maybe even watching stressful things. 00:14:03 Professor Russell Foster: Absolutely. 00:14:03 Krutika Adatia: Because I know when I watch a show that's quite emotionally charged or it's a bit upsetting, it takes me a little bit longer to go to sleep. 00:14:12 Professor Russell Foster: Well, I have to say I've become a coward. I don't watch the evening news any longer. It's just too stressful. And so again, it's identifying the things that do make you anxious and avoiding them. 00:14:25 Krutika Adatia: And it's probably a nice segue talking about screens and watching things. What impact does screen time and certain types of light exposure have on scene? 00:14:36 Professor Russell Foster: I'm so glad you mentioned this because there's an awful lot of nonsense out there. It's another reason I wrote Lifetime. There's a famous experiment that came out from the states which was

looking at a Kindle before you go to sleep. And the press report says, looking at a Kindle, it was called a light emitting book before you go to sleep will disrupt your sleep. Well, you need to look at the experiment. What people were asked to do was look at their Kindle on its brightest light setting for four hours immediately before sleep on five consecutive nights. And what that did at the end of five nights was delay sleep onset by nine minutes. It may have been statistically significant, but biologically that's just meaningless. And what's so interesting is that in those experiments, people were kept under dim light prior to using the Kindle at night. Another group repeated experiment essentially, but exposed people to moderate levels of light during the day for about six and a half hours and any subtle effects were completely abolished. Showing why it's really important to get out during the middle of the day, get some bright light exposure because that will then desensitize the clock sensitivity to light in the evening and reduce the chances of wobbling and moving around the sleep wake cycle. So don't worry if a Kindle is what relaxes you and you can get off to sleep using one, do so. The thing to be very careful about though is the content. Where we do have good data is that if you're using your iPhone or your tablet or whatever, and it can have an alerting effect. It's not the light, it's what it's doing to the brain to alert it. And again, it's all part of that relaxation whereby you need to wind down and yes, sure use a Kindle, but it may be a few pages of Jane Austen, whatever, but it shouldn't be some sort of Xbox frightening video thing. 00:16:33 Krutika Adatia: That's really interesting. So ideally, I don't want to be doom scrolling social media. 00:16:37 Professor Russell Foster: No, no, I think that doom scrolling is exactly right, and I think we all are tempted, but we mustn't because it's again, the great enemy of sleep. 00:16:44 Krutika Adatia: I know we spoke a little bit about this earlier in terms of what we might be able to do to try and get a better sleep, but is there a specific environmental setup that students might want to have in place before they go to sleep to help them sleep better? 00:17:00 Professor Russell Foster: Certainly. I think that to make the bedroom or the place where you sleep a place of calm, and it's very difficult because many bedrooms are also offices and this of course is what happened during Covid. But if you can possibly take away the work space from the sleep space, then that's really good. Make sure there's street lights, have good blackout curtains, make sure the bedroom isn't too warm because many bedrooms are overheated and if it's too hot, it's much more difficult to drop that core body temperature, which was one of the triggers that helps you get off to sleep. So that's really important. I also think, and I think we Brits might be a bit cheap about this, is that we don't invest in decent mattresses and pillows and duvets. I think there's a huge resistance to do that, and yet we spent a third of our lives in bed, so why not have a decent pillow and a decent duvet? And so make sure that's right. Other people will define the sleeping space with a distinctive smell. It may be lavender, it may be whatever. The evidence that it actually works above placebo isn't strong, but I think there's a psychology here. Which is you go into that space, you associate it with sleep, and it can then put you... It's part of that adjustment, that winding down, " I'm now in the sleeping space." And that's reinforced by a distinctive smell. So those would be things for the bedroom. But it's also important that during the day you stop drinking coffee at around about two, three o'clock in the afternoon. Some people are really sensitive to coffee, and what you often find is this sort of cycle of stimulation and then sedation. So you've driven the working day with endless cups of coffee, so you're wired, then you want to approach sleep time. You think, " My goodness, I'm fully awake. What am I going to do?" So you take a few slugs of glasses of wine or alcohol of some sort, or even worse, which are prescription drugs. And what they do is that they are sedatives. They do not provide a biological mimic for sleep. And in fact, alcohol can actually damage some of the wiring, which is consolidating sleep and giving you an improved ability to consolidate memory and actually find solutions to complex problems. So don't use sedatives either, other people's prescriptions or things like alcohol or indeed antihistamines. Which of course some antihistamines, the drowsy ones, you often see people dosing up with those really trying not to try and allow natural sleep to take its course. So yes, I think that's really important. 00:19:41 Krutika Adatia: You've mentioned some really interesting things and a couple of things I resonate with. So you mentioned the duvet, the pillow, not underestimating that, and I'm just thinking about it is helping me understand perhaps my own behavior and emotions that

when I do sometimes go to hotels or holidays and I'm not able to sleep, it's probably because the pillow is not comfortable or I'm just used to my home bed. 00:20:03 Professor Russell Foster: So we go back to smell. And so you might want to take a small amount of your partner's aftershave or perfume or the lavender that you've defined your bed with a few drops on the pillow. Again, it provides that familiarity which makes you feel you are at home and it'll be easier to sleep. 00:20:20 Krutika Adatia: And the interesting point about coffee, I mean, I'm not a coffee drinker, but I do drink tea, but just interesting to know and be mindful of when you have that last cup of coffee. 00:20:30 Professor Russell Foster: And tea. We've switched in our house to decaffeinated tea for many, many years now, and I do think it makes a difference. One of the other problems that many people face is a partner who snores and you need to check that they don't have obstructive sleep apnea, which is the cessation, the stopping of breathing and then this sort of waking up sort of thing. That's dangerous and then you need to see your GP. That's actually really important. But if it's just snoring, then what do you do about it? Well, there are earplugs, but many people can't deal with that. It is absolutely no shame if you can sleep in an alternative sleeping space to go there. So many people say, " Oh, I couldn't possibly do that. It's the end of a relationship." And I say, " No, absolutely not." It's the beginning of a new relationship because you're going to get a decent night's sleep and then the time you'll have together will be more empathetic, you'll have more fun, you'll be less resentful. And so many people, in fact, a 25- year- old came up to me the other day and said, " How old do you have to be before you can sleep in several rooms?" 00:21:31 Krutika Adatia: Brilliant. 00:21:31 Professor Russell Foster: Again, it's horses for courses. What works for you? 00:21:37 Krutika Adatia: So Russell, you've obviously mentioned natural sleep and ways that we can think about meditative techniques to unwind. There's obviously a lot out there in terms of medication or supplements that we can take. What are your thoughts and views about that? 00:21:52 Professor Russell Foster: Well, of course sleeping tablets, ideally you shouldn't use them long- term. The occasional sleeping tablet, just to sort of correct the whole situation is fine. And I think most GPs now will only give you five or seven days supply, and I think you shouldn't push it beyond. So avoid sleeping tablets if you possibly can. A couple of other drugs. So one is magnesium, and I saw some recent data on magnesium, which looked really promising. I wouldn't say that we've got the complete data yet, but magnesium may help some people get off the... It's very difficult because there's always a placebo effect with these issues. But anyway, magnesium may be something you want to try. I don't know of any adverse effects, but obviously you have to be careful. And if you do take magnesium and you're on other medications, you must let your GP know so there's no possibility of a conflict. And I guess melatonin, which is what many people are familiar with. Melatonin can be prescribed by your GP. And of course many of us passing through an airport see endless shelves full of melatonin. So what's the facts? Melatonin is emphatically not a sleep hormone. There are people who don't produce any melatonin because they're on beta blockers, for example, and their sleep is barely affected. So what we do have is some data suggesting that if you take three milligrams of melatonin prior to bed, it can reduce the time it takes to get to sleep, but it won't keep you asleep. But it can reduce the time to get to sleep by about 10 minutes, maybe 20 minutes. And it doesn't work for everybody. About 70% of people has some sort of effect ranging from 20 minutes too much, much lower. In the experiments that had been done, the most efficacious use of melatonin reduced sleep timing by I think 15 minutes or so. So it's not a big effect, but it might help as long as you don't use it routinely. The occasional use of melatonin, I mean, I tried it when I was flying to Australia. I found it didn't work at all for me. So again, occasional use, fine. If it works for you again, fine. I suspect there's a big placebo effect. But those are the two sort of things on the market at the moment. Magnesium and melatonin. As I say, melatonin, you can't buy over the counter in the UK, but of course you can get it all over the place. 00:24:13 Krutika Adatia: That's great. And obviously you've given some great examples of an environment we could create our sleep more, but there might be listeners or students watching or listening to this thinking, " Oh God, I have irregular sleep pattern." And they might be having it often. Could you just sort of spotlight, what kind of impact is that having on their ability to learn? 00:24:33 Professor Russell Foster: Well, it may have no impact. Again, there's lots of variation between individuals, but if you're

waking up and you're not getting back to sleep, it's almost certainly, again, going back to the anxiety and the stress. And it may well be that you'll want to leave the sleeping space and go to somewhere else, keep the lights low, read something, listen to music that is relaxing, and then you will feel tired and then go back to sleep again. The key thing is we do have a condition which is now called sleep anxiety, which is the terror of not falling to sleep or if you wake up, you can't get back to sleep. One trick incidentally is if you've got one of those illuminated digital alarms by the bed, cover it up. Because if you wake up and you glance, you think, " Oh my goodness, I've only got two hours before the alarm goes off." That completely stresses you out and makes many people say, " Oh, well that's it. Might as well get up, drink coffee and do emails." And actually that two hours can be very valuable. So's it about staying calm and then going back to sleep again. It's the ability to use things like mindfulness, other relaxation techniques to get you back to sleep. 00:25:41 Krutika Adatia: So Russell, what is the impact of lack of sleep on cognition and brain health? 00:25:46 Professor Russell Foster: In terms of one's emotional responses, you see that even a couple of nights of no sleep, one's mood fluctuates quite significantly. Irritability increases, anxiety, loss of empathy, the failure to pick up those social signals from friends and family. Risk- taking and impulsivity. This is extraordinary and there's some great studies on this. And so, " Yes, I know I can get through the traffic light before it turns red." No, you won't. And if you weren't tired, you'd never think of doing that sort of thing. Negative salience, and I think this is really important because some lovely studies have been done, which shows that the tired brain remembers negative experiences but forgets the positive ones. So one's whole world view is dominated by this negative salience. So that's a really important effect of not getting enough sleep. And of course we've talked about the use of stimulants and sedatives, but one has to be careful because that can lead into sort of illegal drug use, and that's always a major worry. So that's sort of our emotional responses. Let's think about our cognitive responses. Well, overall one's ability to process information is affected. One area I think is really interesting is the ability to multitask. So what we're constantly doing is being bombarded with information and we have to extract the salient bits and pay attention to that and ignore everything else. And when we're tired, that sort of focus of attention can be very much disrupted. Our ability to multitask, it goes down. We've talked about the memory consolidation, the processing of information, our communication skills, decision- making skills, our creativity, productivity, all of the stuff that makes us... Even our sense of humor. All the wonderful things that make us human are very much affected by even short- term sleep disruption. Now, I don't want to make people more anxious, but I think that it's worth being sensitive to the fact that this is, if you find you're, for example, sliding towards depression, then not getting the sleep that you need can actually nudge you down that path. Long- term sleep disruption, as you see in night shift workers is associated with a whole range of physiological issues, changes in immune response as even in long- term night shift nurses, higher rates of cancer. It's very interesting. The World Health Organization has now classified night shift work as a probable carcinogen because of the data. So it's really important. Also driving. So there's a study a few years ago showing that 57% of junior doctors had either had a crash or a near miss on the drive home after the night shift. Now, most of your students won't be doing night shift work, but it does illustrate the fact that if you're tired, you're going to experience these micro sleeps, which means you could fall asleep at the wheel. And I think if you're vulnerable to mental health issues, then poor sleep can nudge you in that direction, can make it worse. 00:28:47 Krutika Adatia: That's great. It seems like sleep is really integral to so much of our being. 00:28:52 Professor Russell Foster: It is, absolutely. It defines really the conscious state. 00:28:56 Krutika Adatia: I sort of touched on this already, but what are some of the practical tips that we might want to give our listeners and our students who are struggling to stay asleep and fall asleep? 00:29:07 Professor Russell Foster: Well, there are lots of things we can do, as I say, and of course it's a matter of finding out what works for you. But on the rule of thumb, it's that morning light which sets the body clock, which means you can stabilize the sleep wake cycle. And so stick to a regime, ideally don't oversleep at the weekend. You can catch up a bit, but you never do completely. So it's far better to get a stable sleep wake across the seven days of the week rather than massive oversleeping at the weekends. And

of course, that oversleeping at the weekend will mean you miss the morning light, which means that you're not going to get that steady thing. So many students, for example, will have shortened sleep during the week, massively oversleep at the weekends. They don't get the morning light, but they get afternoon and evening light that delays the clock. So it's more difficult to get up on that Monday. And so that's one thing. We've touched on make sure the bedroom isn't too warm, make sure you've got the right bedding. Try and make the sleeping space a place of haven and calm. Don't get stressed if you wake up. Chances are if you stay calm, you will get back to sleep again. 00:30:14 Krutika Adatia: Thank you for all your useful insights and those golden nuggets. I've learnt loads as well that I'm going to take on board. But finally, three top tips from our conversation today that you want to make sure listeners think about. 00:30:28 Professor Russell Foster: Well, I think that we need to embrace our sleep. We've got to absolutely realize, as I said right at the beginning, the quality of our sleep defines the quality of our waking state. It is not an indulgence, it's a critical part of our biology. So much of our ability to function depends upon it, so take it seriously. The second is most people don't have a sleep problem. They have an anxiety issue. So it's finding ways to wind down to relax and not to make sleep (inaudible) to become terrified and worried about sleep. And if you wake up, your chances are you will get back to sleep. So it's all about staying calm. And what were the third thing? I think it would be to be aware that there's an awful lot of variation in our sleep. It's a very dynamic part of our biology. One size does not fit all, and so it's all about defining what our individual needs are and then defending them. I mean, you struggle because you're a morning person, then you had to go out late on a Friday. And sometimes you just have to be strong and say, " I'm sorry, I'm going to be a bit of a party pooper." Obviously not too often, but it's about defining what's good for you. 00:31:41 Krutika Adatia: Thank you so much, Russell. That's been a great conversation. That's it from this episode of On Your Marks. Thank you Russell for chatting with me today. For more information about ACCA exams, you can go to www. accaglobal.com forward/ exams. And to watch the video version of this podcast, check out the link in the show notes. I'm Krutika Adatia and this has been On Your Marks. On Your Marks is a fresh air production for ACCA. Its lead producer is Eva Higginbotham and its executive producer is Annie Day. The videographer is Yohan Forbes, and the sound engineer is Basil Oxtoby. See you next time.