Is Your Home Keeping You Awake? Professor Russell Foster Rethinks the Rules of Sleep

Homing

In this episode of Homing, Professor Russell Foster, a leading expert in circadian neuroscience at the University of Oxford, challenges comm

Key takeaways

• Sleep duration varies widely; there's no universal 'eight hours' rule—individual needs differ.
• Waking up during the night is normal and shouldn't cause anxiety.

Main topics

• The science of circadian rhythms and their impact on sleep
• Debunking the myth of eight hours of sleep

Notable quotes

"Sleep is not an enemy, it's a profound friend. If we embrace it, we'll get the sleep that we need."

Conclusion

Professor Foster concludes by urging listeners to shift their mindset around

Transcript preview

Speaker 1 (0:03) Hello, welcome to a new episode of Homing. I hope you've all been having a really good summer or a good winter, as the case may be. I was looking at our stats the other day and homing has a big following now in Australia and New Zealand. And so a heartfelt hello to all of our friends over there. Today we are talking about one of the most elemental of homing behaviours, which of course is sleep. We spend about a third of our lives doing it. And I don't know about you, but I've had a bit of a checkered history with sleep. There have been times in my life when I've really struggled with it. But I think I've come to realise that setting your home up in the right way can actually really help. So with that in mind, my guest today is one of the world's leading experts on sleep. And his name is Professor Russell Foster. And he is Professor of Circadian Neuroscience at the University of Oxford. Russell and I were introduced by my literary agent. Tom Killingbeck, who also published Russell's brilliant book, which is called Lifetime, The New Science of the Body Clock and How It Can Revolutionize Your Sleep and Health. Let me just say actually up front that this is not a podcast that's going to fill your head with loads of strict rules that you have to adhere to to get the perfect night's sleep. It's quite the opposite, in fact. Russell is a surprisingly easygoing guy with a very sensible approach, I think. So he was very reassuring on lots of things, including... you know eight hours isn't the magic number that we all think it is it's perfectly normal to wake up in the middle of the night and we shouldn't worry about that too much he's not a fan of sleep trackers so they often do more harm than good and this is a really big one screen time before bed he's not worried about it so i was quite pleased about that perhaps the most reassuring idea is that we need to stop trying so hard when it comes to sleep so as russell points out the more we worry about it the more elusive it tends to become. I found this really interesting. I think it's a really quite unique take on this issue of sleep that we all mull over and have difficulties with from time to time. I really enjoyed talking to Russell and I hope you enjoy it too. Here it is. Speaker 1 (2:16) Hi, Russell. Hi, Matt. Great to join you. Yeah, thank you so much for being here. Thanks for being on Homing. I'm really looking forward to talking to you. I know we've been trying to set this up for a little while. I know. I'm sorry. Speaker 2 (2:27) It's been constant travel this year for all the right reasons, but I do apologise. No, Speaker 1 (2:32) no, no, you don't need to apologise. You know, sleep is a subject that I think we all care about very deeply. I've had my own ups and downs with it over the years, so I'm really interested to find out. a few things about sleep in relation to our home environments, in relation to our environments in general, and a few things we might be able to take away today. But my first question for you is one that I usually ask. In your opinion, this word home, what does it mean? How would you define it, would you say? Speaker 2 (3:03) I guess for me, it would be the place where I feel I can relax. I don't feel threatened. It's a space I like to share with others, but also perfectly happy being there on my own. And ideally, it's a place that you can be happy. Speaker 1 (3:21) Very good. And was it a happy place for you when you were growing up out of interest? What kind of environment were you raised in? Speaker 2 (3:30) Luckily, I spent a great deal of time with my grandparents. So they made a home incredibly protective and wonderful. I mean, there were a bunch of stuff going on within the family. And so I did spend a great deal of time with my grandparents. And I think I got to know them remarkably well. I mean, it's extraordinary. They were born in the Edwardian era, you know, 1906 and 1909. And yet they were some of the most... remarkable, kind, generous individuals I've ever met. And I gained a great deal with spending time with them. And in fact, on the topic of home, when we bought this house, and the children are in their 30s now, we always wanted them to have a bedroom that they could come back to, that they could regard as theirs. And the joy is that they come home a lot. It was our daughter's birthday just recently. And so she had a whole bunch of people over for a party. And so I think it's a place where you can feel calm and happy. And I got a great deal from living with my grandparents. Speaker 1 (4:33) That's lovely. Well, you mentioned the bedroom there. What has been your relationship like with sleep over the years? Why have you spent your career trying to understand this particular thing? Well, my sleep is pretty good. Speaker 2 (4:50) I mean, I'm a late chronotype, which means I like to go to bed late and get up late. But of course, that changes as you get older. But certainly as a student, I would go to bed really quite later and if I could, sleep in. But it's on the whole been pretty good. Why have I decided to study it? Well, I think it's one of those... extraordinary frontiers in biosciences. You know, it's such a profound behaviour. You know, 30 % of our lives could be spent asleep. And yet we haven't until fairly recently understood why it's so fundamental and what's so important about sleep. And I find that mystery really exciting. Speaker 1 (5:29) Okay, well, let's go there then. Why is it so important? And, you know, why do we sleep at all? Yeah, I Speaker 2 (5:34) think that what we've understood over the past 15, 20 years, perhaps, is sleep is not this luxury and indulgence, which is only meant for wimps, but it's one of our pillars of health. And so... Without sleep, we have a breakdown in our emotional responses. So, for example, we show more irritability, anxiety. We do stupid and unreflective things. We do risk-taking. One fascinating set of studies has shown that the tired brain remembers negative experiences but forgets positive ones. So when you're tired, your whole worldview is distorted. You know, the tired brain will crave stimulants like caffeine to stay awake during the day. and of course to reverse that at night it may resort to alcohol which is a sedative and of course doesn't provide a biological mimic for sleep. Cognitive responses also fall apart. Our ability to not only remember things but process information, come up with innovative solutions to complex problems. Our sense of humour begins to break down. All the things that allow us to be remarkable creatures, to be humans. our ability to communicate, interact with others, come up with new ideas, is all... really quite profoundly influenced by poor sleep. And of course, long term, we activate a whole range of biological triggers, which means that we are at greater risk for cardiovascular disease, greater risk for cancer, we have immune suppression, a greater vulnerability to mental health. And there's even, in some people, a greater vulnerability to developing dementia, if you get poor sleep in your middle years. So I think so many people think of poor sleep as feeling sort of tired at an inconvenient time, whereas in fact it impacts globally. The quality of our sleep defines the quality of our consciousness and to a large extent who we are. Speaker 1 (7:30) So we're always told to aim for this mythical eight hours, right? Is that the right thing? How do we know if we're getting enough sleep? Speaker 2 (7:37) Oh, this mythical eight hours. It's why I wrote... my book Lifetime, because I was really fed up with the sergeant majors of sleep screaming, you know, you must get eight hours. And of course, sleep is a very variable, very dynamic thing. And it, you know, one shoe size does not fit all and one sleep size doesn't fit all. So the key thing is that. You know you're not getting enough sleep, and it's kind of straightforward, if you don't feel you can function optimally the next day. We can all get a sense of whether we're firing on all cylinders or not. If you require an alarm clock or somebody to get you out of bed, if it takes you a long time to wake up, if you've got this sort of grogginess, sleep inertia, if you oversleep, for example, on free days or on holiday, if your friends or family tell you that, hang on, you're a bit more irritable. You don't have as much empathy. You seem to be more impulsive. If you're just not feeling right. And the problem is that we tend to want to listen to devices rather than ourselves. And we're the best judge of whether we've had a good night of sleep or not. Speaker 1 (8:47) Okay. Well, that's, yeah, that's fair enough. So what's the sort of minimum that people tend to be able to get away with? I mean, you know, you do meet some people and they sort of say, I just don't need a lot of sleep. How many hours are we talking there? Speaker 2 (8:59) Well, there's two answers to that question. The first thing is the tired brain often can be deluding itself. And a classic example is taxi drivers. You get into a taxi. They say, would you work the night shift? And they say, yeah. And I say, is it a problem? And they say, no, no, it's no problem at all. And then you bring them into the lab and you test their cognitive abilities. And they're terrible. So often we don't. quite know how tired we are because we can override it when we have to. The other thing is that the National Sleep Foundation have said that sort of the healthy range, and this isn't the average, this is the range, is somewhere between six hours and perhaps 10, 10 and a half hours. So it's a really quite a broad range. And of course, it changes as we age. So when we're babies, we may sleep 19 hours in 24. The time we're in our teens, on average, it's nine hours, but some will need more, some less. When you get to old age, it's about seven hours or so. On average, some people will still need much more or much less. And it really is, I don't want to put a figure on it because it's such an individual thing. Yeah, Speaker 1 (10:09) yeah, yeah. Speaker 2 (10:09) That makes sense. Can we ever catch up on sleep that we've lost? Yeah. So this is, again, a really important point because there's some very nice experiments here where people were only allowed to sleep about four hours a night as opposed to people who slept... Normally. And over this time, individuals were monitored for their cognitive ability and emotional responses. And as the four-hour days went on, the cognitive abilities dropped and the irritability increased. Then they were allowed to sleep for a couple of days. So it's a bit like having a very demanding week and then sleeping over the weekend or sleeping excessively over the weekend. They did catch up partially, but they didn't catch up fully. So they were still starting their Monday morning with a bit of sleep debt. So yes, you can catch up. But as we'll discuss later, one of the problems of oversleeping in the morning is that you miss morning light. And I know we're Speaker 1 (11:10) going Speaker 2 (11:10) to get to that and explain why morning light is so important. So that can be a real problem. Speaker 1 (11:15) Okay. Well, let's move on to the body clock. So this circadian rhythm that we read about and we hear about, what is that? What does that mean? Speaker 2 (11:24) Well, you can think of the body clock as being an internal day. And why do we need it? Well, what our biology needs to do is deliver... the right stuff at the right concentrations to the right tissues and organs at the right time of day. And what I mean by right time of day is to cope with the extremely varied demands of rest activity, light and dark, as we sit on a planet that revolves around the sun. I mean, it's really important to emphasize, and it's such an obvious thing that we don't... We don't often think about it. I mean, this revolution of the Earth on its axis produces profoundly different environments. And essentially all life on Earth has evolved to deal with those big changes. Now, what the body clock is doing is providing a time structure to anticipate those different demands of our physiology and so tweak biology. So, for example, blood pressure, the release of glucose rises in anticipation of the more. morning, an activity where we need more glucose, we need our blood to get those nutrients to the more metabolically active tissues. And then at the end of the day... glucose metabolism decreases, blood pressure decreases in anticipation of body temperature. It decreases in anticipation of sleep. So what the clock is doing is providing this time structure for life. And without that time structure, we can't do the right thing at the right time, and our biology falls apart. Now, I've likened this to an orchestra, whereby all the members of the orchestra are playing at a slightly different volume and a slightly different time. And so instead of a... beautiful symphony, we have this cacophony of sound. And that's what happens when our biological timing, as dictated by the circadian system, begins to Speaker 1 (13:12) fall apart. I see. That's a really good way of explaining it. And what are the sort of environmental cues that we need to be able to maintain this rhythm? Speaker 2 (13:22) Well, the first thing is that... The human body clock, like all body clocks, circadian rhythms, are not exactly 24 hours. And for about 90 % of us, it's slightly longer than 24 hours. And what we need is a daily adjustment by the light-dark cycle. And it's light that provides the most important time giver to the internal clock. And morning light is especially important for us. And let me explain why. So light has different effects at different times. Morning light tends to advance the clock, make us get up earlier and go to bed earlier the next day, whereas dusk light delays the clock. We want to go to bed later and get up later the next day. So as the seasons expand and contract, we're being nudged forward and then back in accordance with the changing light-dark cycle. Now, why morning light is so very important is that the body clock, as I said, is slightly longer than 24 hours. So it's drifting later. So it needs a daily net advance to drag it into alignments. And that's what morning light does. It drags a slightly delayed clock forward by advancing the clock to make it beautifully aligned with a light-dark cycle. So that's why we all bang on about