Feel Better, Live More with Dr Rangan Chatterjee - BITESIZE | Do This Every Morning to Optimise Your Health, Boost Your Mood and Improve Your Sleep | Professor Russell Foster #488

Episode Date: October 24, 2024

Today's guest shares some of the latest research on using circadian science to optimise our sleep and transform our health.   Feel Better Live More Bitesize is my weekly podcast for your mind, body, and heart. Each week I’ll be featuring inspirational stories and practical tips from some of my former guests.   Today’s clip is from episode 424 of the podcast Russell Foster, a Professor of Circadian Neuroscience at Oxford University.   Modern life has seen us push into the night, staying up later and extending our social and work lives around the clock.   In this clip, Russell shares why getting the right light at the right times can optimise our health, boost our mood and improve our sleep.   Thanks to our sponsor https://www.drinkag1.com/livemore Support the podcast and enjoy Ad-Free episodes. Try FREE for 7 days on Apple Podcasts https://apple.co/feelbetterlivemore. For other podcast platforms go to https://fblm.supercast.com. Show notes and the full podcast are available at https://drchatterjee.com/424   DISCLAIMER: The content in the podcast and on this webpage is not intended to constitute or be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or other qualified health care provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have heard on the podcast or on my website.

Today's Bite Size episode is brought to you by AG1, a science-driven daily health drink with over 70 essential nutrients to support your overall health. It includes vitamin C and zinc, which helps support a healthy immune system, something that is really important at this time of year. It also contains prebiotics and digestive enzymes that help support your gut health. It's really tasty and has been in my own life for over five years. Until the end of January, AG1 are giving a limited time offer. Usually they offer my listeners a one-year supply of vitamin D and K2 and five free travel packs with their first order. But until the end of January, they are doubling the five free travel packs to

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 424 of the podcast with Russell Foster, a professor of circadian neuroscience at Oxford University. In this clip, he shares why getting the right light at the right times can optimize our health, boost our mood, and improve our sleep. We, as a society, don't see light as a drug. We just think, well, we can expose ourselves to whatever light we want, whenever we want. Light is separate to our lives. We get on with our lives,

we do our work, we go on social media, we see our friends, we do whatever, but we don't give attention to light. So what is morning light? Why is it so important? And how much do we need? Yeah. So we have this internal clock, which is fine-tuning our biology to the very demands of the 24-hour day. And what is it? You say internal clock. Many of us picture a clock on our desk, right? So when you say we have an internal clock, what does that look like? Well, actually, there is a master clock within the brain, and it's called the suprachiasmatic nuclei. So, essentially, you can think about where this is. As the optic nerves go into the brain and fuse, sitting above there is a small paired structure of about 50,000 cells. And each one of those cells is capable of generating an endogenous 24-hour rhythm. I mean,

it's just extraordinary. And it's based upon a molecular feedback loop. So clock genes are turned on, they make their proteins. Those proteins then form a complex. They then go into the nucleus and turn off their own genes. The protein complex is then degraded, and then the whole thing can start again. And so it's a biological oscillation of about 24 hours. But it's not exactly 24 hours.

And so it needs to be set to the real day. So the internal day needs to be aligned to the external day. And the most important thing for that, it's not the only thing, but the most important thing is light. Now, light does different things to the clock at different times. So morning light makes us get up early. It advances the clock. Evening light delays the clock, makes us get up later. Now, because most of us, 90% of us, have a body clock that is slightly longer than 24 hours, we, under constant conditions, would drift later and later and later.

So what we need to be entrained to get that internal clock aligned to the external world is a daily nudge, an advance. That's why morning light is so important, because it gives us that advance, which is what we need on a daily basis. So interestingly, we did some studies on some students all over the world. And of course, students are notoriously late types. But we found that the later the chronotype, and I know we touched on chronotypes last time, the more evening light they got, which would delay the clock at the expense of morning light. So they were sleeping through, not getting the advancing morning light,

but they're out in the late afternoon, early evening, getting the dusk light, which is delaying the clock even further. So when we see light, it's so important. So we want to get light exposure, ideally natural light outside, as close to our wake-up time as possible. Yeah, exactly. Now, a couple of things to elaborate on there. We're recording this conversation in January in the UK.

It can often be 8am until you're getting morning light. So many children, many adults are having to get up, let's say at 6.30am to get ready for their day's activities. Your advice is you need to get morning light as soon as possible. Now, morning light may not be available from the outside until 90 minutes after that. So what's your advice with respect to that? And also, what does indoor lighting do and these kind of sad lamps? Are they useful?

Well, they're certainly useful. And I think we could learn something from our Scandinavian cousins here. And so in Tromso, which I visited, it was the most extraordinary place. Where's Tromso? Tromso, northern Norway. And it's in the Arctic Circle.

And of course, it's dark for two months of the year. And what the families do there is that they will have a light box and it's set to produce more than 2,000 lux. And we can talk about lux levels in a moment. For 30 minutes, so 2,000 plus lux, perhaps as high as 10,000 lux in some cases. And they have their breakfast in a moment for 30 minutes, so 2,000 plus lux, perhaps as high as 10,000 lux in some cases. And they have their breakfast in a room where there's artificial light, and they use that to set the clock to the external world. Of course, there's not much of a light-dark cycle, but of

course, they're stabilizing it in a sense for social reasons. And have they done that on the basis of scientific experiments? Or has it been something that they've figured out over time, we need to do this for our physical and mental well-being? I think it's a bit of both. I mean, we've got good data showing that morning light is really important for stabilising sleep-wake. And also, you mentioned seasonal affective disorder. The treatment, I mean, some data for SAD and light

is really interesting. Many of us were very skeptical when this first emerged. You know, say, oh, well, you know, sit in front of a light box. What's the control? You know, you sit in front of a light box and you don't turn the lights on. You can, you know, you work out that it's not going to work. So, is it just a placebo effect? And then a range of much more sophisticated experiments showed that it really was the light. And one fascinating study compared non-seasonal depression and light, and they compared placebo, Prozac, and 10,000 lux for 30 minutes in the morning. And light was more effective than placebo at two weeks.

Prozac was only statistically significant at eight weeks. And then light was more effective than Prozac. So light seems to be very powerful for both non-seasonal and seasonal depression. This is a really interesting point, something I wanted to discuss with you today. This idea that light is medicine, this idea that light is a drug. Your trial that you just mentioned there, or certainly the trial you're citing, is really comparing light to a drug. Yes, yes, absolutely. So in your view, should we consider light as powerful as drugs? I think we absolutely can.

And it would be naive not to think that for the following reason. You know, all life on Earth has evolved on a planet that rotates once every 24 hours. We're exposed to a light-dark cycle. The light-dark cycle has dominated our evolution and our biology. illuminated our evolution and our biology. And because from, what, the 1950s, we could produce cheap, affordable, efficient light, we've invaded the night. And we've thrown away this incredible part of our biology as a result. And it's fascinating that, you know, the humans are wonderful. I mean, we're remarkably arrogant. We think we can do whatever we want, whatever time we choose.

I mean, you know, it's part of the success story. But actually, we do it at some considerable cost. And I think it's about tuning in to those incredibly powerful biological drivers, environmental drivers of our biology. You mentioned Lux before, which of course is a unit of light. Could you

expand on lux? What exactly is it? And maybe give us some examples of the amount of lux we're often exposed to when we're either inside or outside. Yeah. So lux comes in values. So if we think about the sort of light that we'd see outside, so shortly after dawn on a clear day, you would have about 10,000 lux. By noon, that could get to 100,000 lux, even in Britain. No, you know, it's not common. Do we just measure it as a static measurement,

or is it more if you are outside on a sunny day in July in the UK for 10 minutes, you get X amount of lux. If you're there for 20 minutes, you get Y amount of lux. Is it like that? Yeah, it's certainly additive. And of course, it's constantly fluctuating because of cloud cover and whether you're moving inside or under a tree or whatever. But if you just took

your lux meter out and you pointed it skyward, you could get up to 100,000 lux on a bright, bright sunny day. Most of the time, it's going to be something around 50,000, 60,000 lux. But as we go inside, this is where the big changes are occurring. So if you stand on a reasonable sunny day and you point the meter at the window, you could get between 3,000 lux and 1,000 lux. Walk two to three meters into the middle of the room and it's dropped to maybe as little as 100 lux. And why is that a problem? Or a potential problem? Well, yeah. And of course, the sorts of levels of light

you're seeing in the evening would be something like 90 lux in most domestic settings. Even with bright kitchen LED lights on? It varies, of course, a lot. And kitchens now are very well illuminated. So that would be more. That would be 400, 500, maybe even 600 lux.

So the sort of light you get from a Kindle, for example, on maximum setting would be 30 lux. So very low. So low, yeah. And so what does it all mean? Well, the circadian system requires relatively bright light over an extended period of time. And so there's a lot of controversy at the moment

because people have said, okay, well, in fact, domestic light setting, let's say 100 lux, will actually shift the clock. But you have to have seven and a half hours of light exposure to get any effects. So it's a good example of where intensity and duration are being titrated and integrated by the circadian system. However, other more recent studies have shown that actually those low levels of light, even for seven hours or so,

are completely abolished if you've seen relatively bright light during the day. So we said that dawn and dusk is sort of the most important times for shifting the clock, but the clock sensitivity is being gated by the sort of light exposure that you get during the day. So what these studies showed is that 500 lux or more during the day for four or five hours would actually abolish even subtle effects of dim light in the evening which i think is really interesting so you're initially saying that essentially that the lux you will expose your

eye to outside dramatically outweighs anything you could get inside broadly speaking yeah broadly speaking which is why getting outside, particularly in the morning, is so important to set the circadian rhythm. Exactly. Unless you use a light box, which is in the 2,000 to 10,000 range. Like you mentioned before in Northern Norway,

what they're using. Exactly. Okay. Then you were saying there was some research, and I know you touched on this last time, I think it was the Harvard research, showing that actually light exposure in the evening will delay the clock, but it was seven hours plus.

It was a longer, well, the particular experiment, individuals were exposed to a Kindle, brightest intensity for five consecutive nights for four hours before bedtime. And that delayed sleep onset just statistically significantly by 10 minutes. So it had an effect, but it was a small effect. But what's so important is that the latest studies showing that if you had reasonable levels of light during the day abolished those

small effects of reading a light emitting e-book. Yeah. And this is something I became aware of maybe five, six years ago. I was reading some research that indicated that if you get a lot of light exposure in the day, it mitigates and insulates you from some of the negative impacts of light at night. And you're saying more research is now supporting that. Exactly, yes. So if you work outdoor for whatever reason,

or you're able to get out for, I don't know, a one-hour walk at lunchtime. I know many people in offices probably can't do that, but if you can walk to work, walk back from work, assuming it's light outside. Yeah, get off the tube a bit earlier so you can extend that walk. It's cumulative.

The more light exposure you get in the day, the more it insulates you from nighttime light exposure. That's, I think, very empowering because there is a lot of concern over nighttime light exposure. You also mentioned in our first conversation that light exposure in the evening may not delay the clock so much, but it increases alertness. I really want to unpick that because a lot of people will report to me that when they're not looking at screens for, let's say, an hour before bed, and I've seen this in my own life, when I'm not, my sleep is much better. I fall asleep quicker and I'm more rested when I wake up. Yet some of this research is saying it may not be to do with the clock.

That's right. Can you help us understand that? So of course, light is critically important for regulating the circadian system, but light can have a direct alerting effect upon the brain. And so we're not absolutely, it looks like lower levels of light can have an alerting effect that won't have such an effect upon the circadian system. So it still could keep you up? Yes, but it's not by shifting the clock. But it's very difficult to disentangle because there's the light alerting effect. But if you're working on a computer screen and you're, let's say, doing social media and you're being energized by emails and you're doing all that sort of stuff,

that will also have an alerting effect. So, in fact, relatively low levels of light and other activities that have an alerting effect on the brain could act synergistically. So, I think the rule of thumb would be, ideally don't use devices for 30 minutes and maybe an hour before bedtime for two reasons. One, it could have an alerting effect upon the brain, but also because of the sorts of alerting effect upon the brain, but also because of the sorts of alerting effects that social media, emails, and all that, and just thinking

does if you're sitting in front of a computer screen. And it's all part of the process of winding down. As we discussed last time, most people don't have a sleep problem. They have an anxiety or a sleep issue. And the more you can do to relax and wind down before that transition into sleep, the easier sleep will become. Hope you enjoyed that bite-sized clip. Do spread the love by sharing this episode with your friends and family. And if you want more, why not go back and listen to the original full conversation with my guest. If you enjoyed this episode, I think you will really enjoy my bite-sized Friday email. It's called the Friday Five. And each week I share things that I do not

share on social media. It contains five short doses of positivity, articles or books that I'm reading, quotes that I'm thinking about, exciting research I've come across, and so much more. I really think you're going to love it. The goal is for it to be a small yet powerful dose of feel-good to get you ready for the weekend. You can sign up for it free of charge at drchatterjee.com forward slash Friday Five. I hope you have a wonderful weekend. Make sure you have pressed subscribe, and I'll be back next week with my long form conversational Wednesday and the latest episode of Bite Science next Friday.