Feel Better, Live More with Dr Rangan Chatterjee - BITESIZE | How to Master Your Sleep | Professor Russell Foster #357

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Starting point is 00:00:51 10. And these packs are perfect for keeping in your backpack, office, or car. If you want to take advantage of this limited time offer, all you have to do is go to drinkag1.com forward slash live more. Welcome to Feel Better Live More Bite Size, your weekly dose of positivity and optimism to get you ready for the weekend. Today's clip is from episode 292 of the podcast with Russell Foster, a professor of circadian neuroscience at Oxford University. In this clip, we discuss how a lack of sleep can affect our health, and Russell shares some of his top tips for better sleep. How sleep deprived are we as a society? And then secondly, what are those consequences?

Starting point is 00:02:00 Sleep deprivation varies a lot because, of course, sleep need varies a lot. But I think on average, people are saying that we're sleeping one, maybe two hours less than we were in the 1950s. And I think those data are pretty robust. And certainly, that's the case in adolescence, big time. And so, what are the consequences? Well, short-term sleep loss, we see changes in our emotions and our cognitive performance. So, we increase levels of irritability, the failure to process information accurately. We do stupid and unreflective things. We are less empathetic. I mean, it's really fascinating. We fail to pick up the social signals of friends and family. We're less socially connected.

Starting point is 00:02:48 We have reduced capacity to remember things. We are less creative. So all the things, reduced sense of humor. I mean, you know, all the things that make us this extraordinary creature, you know, these amazing humans, you know, all this creativity and wonderful interconnectedness goes as a result of even short-term sleep loss. Longer term, we also see that there's changes in immune responses. So it's likely because we're chronically tired, we're activating in a sustained way the stress axis, And that's going to push up blood pressure, it's going to throw glucose into the circulation. So it pre then disposes to things like obesity,

Starting point is 00:03:31 type two diabetes, and indeed, because of the suppression of the immune system, higher rates of infection, and indeed, cancer. Chronic sleep loss is so much more than feeling tired at an inappropriate time. It's associated with an impact upon our health at every level. Yeah, I mean, what you just went through there, it impacts negatively our day-to-day lives. You mentioned empathy. I mean, what do we need for good quality relationships with partners, children, work colleagues, family. We need empathy. So much of the stuff going on within the brain and the body whilst we sleep defines our ability to function during the day. And you know, it's really, we've got to start embracing sleep.

Starting point is 00:04:17 There's a lot in your book about our body clock, our body clocks, I i should say and what they all do what influences them one thing i've felt an experience when people when my patients when members of the public are thinking about sleep they're often thinking about the evening they're thinking about what do i do just before bed and of course that's important we're definitely going to get to that but i thought it would be useful particularly through the lens of the clock i guess talk about the morning why is what we do first thing in the morning so important for our ability to sleep at night yeah for our biology to work you need the right stuff the right concentration delivered to the right tissues and organs at the right time of day. And of course,

Starting point is 00:05:05 our circadian and sleep-wake systems do that. So if you disrupt them, you have a whole bunch of vulnerable points where things could fall apart. So we have this circadian system, this sort of internal representation of a biological day. And what it does is anticipate the very demands of the rest activity, the sleep-wake cycle. Now, for it to be of any use, the internal day needs to be set to the real day, the astronomical day. And the classic mismatch between biological time and environmental time is jet lag. And we eventually get over jet lag as a result of exposure to the light-dark cycle in the new time zone. as a result of exposure to the light-dark cycle in the new time zone.

Starting point is 00:05:51 But what we require in any time zone is daily exposure to the light-dark cycle, and particularly morning light for 90% of us. Most of us have either a long body clock or a body clock that's slightly longer. And so it will naturally drift a little bit later and later and later each day and the effects of light are not the same morning light advances the clock makes it makes us get up earlier and go to bed earlier whereas dusk light delays the clock it makes us go to bed later and get up later and so what morning light does to us is take this drifting clock and shoves it forward a bit in time so it's beautifully aligned. Now, of course, this is important at every level. I mean, we did a study a few years

Starting point is 00:06:30 ago on teenagers all over the world and found that the later the chronotype, the eveningness versus morningness, the greater the evening light these young people got. So they were getting up after morning, so not getting the morning light, which would young people got. So they were getting up after morning. So not getting the morning light, which would advance the clock, but they were getting evening light, which would delay the clock. So part of their going to bed late and getting up late is when they were actually seeing light. And so morning light, for most of us,

Starting point is 00:07:00 is really important to set the biological clock, which then aligns all of our activity including the sleep-wake cycle to the appropriate time of day and this light exposure whereas in the morning it advances the clock and in the evening it delays the clock so pushes it back what light exposure are we talking about here because let's say in the evening or at dusk you saw natural lights not artificial lights yeah does that still do the same thing at pushing it back or does that have a different wavelength that doesn't affect us in the same way well you're you're sort of impinging upon what i've sort of been working on for a long time which is how does how does light interact with the body

Starting point is 00:07:43 clock and the first sort of extraordinary finding was that the visual cells within the eye, the rods and the cones, are not required to detect that dawn-dusk cycle. There's a third photoreceptor within the eye. And we've been working out most recently how those receptors interact with this sort of master clock within the brain.

Starting point is 00:08:04 So that's one thing. The second thing is that these photoreceptors need quite a bit of light. So we don't really appreciate, because our visual system is so good, but we live our lives in dim, dark caves. So shortly after dawn, natural light is some 50 to 100 times brighter than average domestic light conditions. And so, really what the clock is looking for is a bright light signal. And so, we're talking in the hundreds to thousands of lux range. So, if you think of natural light, okay, moonlight would be

Starting point is 00:08:41 0.01 lux, and a bright sunny day, even in the UK, can just about get up to 100,000 lux. And those weird, amazing photoreceptors need, as I say, this sort of 100 to 1,000 lux range. Now, it's complicated because it depends upon how long you're exposed to that light. So you can compensate to some extent for a lower light intensity by increasing the duration. And this is where we fall into some problems, because there's a lot of stuff out there saying you shouldn't look at a kindle immediately before you go to bed, because it'll shift the biological clock. So the most detailed study, which was from a group at Harvard, asked people to look at a Kindle on its brightest intensity four hours before bedtime. And they asked them to do this on five consecutive nights.

Starting point is 00:09:35 And after that, on the fifth day, sleep was delayed by an average of 10 minutes. And it was just statistical. And as one of my colleagues said, well, it may be statistically significant, but it's biologically meaningless. And so, but we do know that light in the evening can delay the clock. But how much and what intensity

Starting point is 00:09:57 and for how long is still being resolved? Clearly, the brighter the light and the longer you see it before bedtime could shift the clock. But what we do know that light is doing is increasing alertness being resolved. Clearly, the brighter the light and the longer you see it before bedtime could shift the clock. But what we do know that light is doing is increasing alertness and therefore delaying sleep onset. So it's probably not the light from the devices changing the clock, but it's the light from the devices changing alertness and therefore delaying sleep. Yeah, super, super interesting. So if we just stick to what that study showed,

Starting point is 00:10:25 that was on a Kindle. I know when I've heard you speak before that you regard Kindles as quite different from smartphones or looking at social media. Perhaps you could explain why that is. Well, because a Kindle is fairly, you know, you're just reading it basically. Whereas a smartphone, you're checking your emails, you're looking at social media, you're just reading it basically. Whereas a smartphone, you're checking your emails, you're looking at social media, you're checking the news, you might even be listening to music at the same time. And so these are really interactive devices and they will be increasing alertness and therefore delaying sleep onset. Yeah, so interesting. You know, Russell, one of the things that's helped my sleep a lot over the past years, quite a few things recently, one is to avoid any sort of emotional stimulation in the evening.

Starting point is 00:11:08 So I've, this has probably been going on for six or seven years now, I've had to educate the people around me, particularly my family, that I go to bed early, I wake up early. I just, it suits me. I don't know if I am actually a morning type. I certainly live like a morning type, but then I set everything up around that because ever since my kids were born, they've always got up really early. And I know for me, I'm a much better human being when I've had time to myself in the morning before anyone else is there. So I would shift it back so that I could have an hour to myself before they wake up. So I'm now in a

Starting point is 00:11:45 position where I usually go to bed by nine o'clock at the latest, and I'm up by 5am at the latest. When I can stick to that consistently, I feel fantastic. Yeah. And that's exactly what we should all be doing. We should be defining, you know, what our biological needs are, and also, of course, what our social needs are, societal needs are, and particularly our work, and try and tune ourselves accordingly. You know, it's so important. Yeah, and so that process required me to help people around me understand that, look, after seven, half seven, I really do not want to be contacted with anything unless it's an emergency.

Starting point is 00:12:26 I know. And of course, it's very difficult because of course, towards bedtime is the only time when many couples get chance to talk about stuff. But of course, it can be charged. And so, for example, I have banned any discussion of family finances before we go to bed or anything like that. You have to carve out time at a different time. The other thing that's interesting about your earlier bedtimes, of course, is you'll be eating much earlier. And that can be very important. The data now are very clear that trying to concentrate one's calorie intake

Starting point is 00:13:01 during breakfast and lunchtime and a very light supper or an earlier supper that you can possibly manage is better for our metabolic health and reduces the chances of weight gain, obesity and type 2 diabetes. So you have a double advantage there by going to bed earlier. One of the things that has really helped me over the last years is, you know, I try my best not to be on my screen before bed. Usually I'm good with that, although I'm human and, you know, I fall prey to the temptation like anyone else might do. I try and read before bed. And in my bedside lamp, I put these low lux bulbs in. So I've got this like amber low lux bulb. Now, I really feel it's made a massive

Starting point is 00:13:47 difference the way I feel. It just feels softer. And whenever, if I'm in another room or staying somewhere where they've got a usual bulb and I think, wow, this is quite obnoxiously bright. So are these things helpful in your view? They are indeed. It sort of maps on again to the biology. This is what you'd certainly recommend because the lower the light, you'll reduce alertness and it'll be easier to get to sleep. And of course, if it's bright light, then of course you will shift the clock. But most artificial light is not going to have much of an effect. But the other thing, of course, is that what you're doing is defining the sleeping space. And so, for example, we need to sort of reinforce the fact that the bedroom or the

Starting point is 00:14:32 sleeping space is what you do when you want to go to sleep. So, you have a lovely mattress, you have great pillows, you might even have a distinctive smell, like lavender or something else, because you associate that distinctive smell with the sleep state. And I know people who, when they go and they travel and they're staying in a hotel room, they'll take a partner's perfume or aftershave because that defines the sleeping space for them. So the extent to which those are almost placebo effects doesn't matter. If they work, then you should embrace them. You know, I mentioned that amber bulbs that I have in my bedside lamps. I think also, as well as the biological explanation, I think there's also, I guess, something behavioral about them for me in terms of it's, it signals to me,

Starting point is 00:15:25 oh, it's now evening time. It's rest time. It's not stimulation time. Do you know what I mean? So I think sometimes- Yeah, it's that winding down. We assume that we can go from a fully conscious state, you know, the gear analogy, you know, going from first gear to fifth gear, you can't do it. You have to do it through stages. And again, winding down from the wake state to the sleep state requires an adjustment. And whether that's, as you were saying, you enjoy reading some novel under relatively dim light before going to bed. Some people listen to music or something else that they find relaxing. And it's adopting those behaviors that make the transition easier. And again, it's, as you were saying, it's and it's it's adopting those behaviors that make the transition easier and

Starting point is 00:16:06 again it's it's it's as you were saying it's the brain knows what's coming next and what's coming next is sleep hope you enjoyed that bite-sized clip i hope you have a wonderful weekend and i'll be back next week with my long-form conversational wednesday and the latest episode of bite science next friday conversational Wednesday and the latest episode of Byte Science next Friday.

Feel Better, Live More with Dr Rangan Chatterjee - BITESIZE | How to Master Your Sleep | Professor Russell Foster #357

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