Hi there, it's Matt here and welcome back to the podcast. Now, in our previous episode. We spoke about the role of temperature at the start of the night and how we have to warm up to cool down to fall asleep. In this episode. We're going to discuss how temperature can then help you stay asleep across the night. And finally, we will reverse engineer.
The trick and we will speak about how temperature can help you. Wake up in the mornings. Let's return to that whole body temperature suit that I described in the previous episode. If you don't remember, it's designed by a wonderful sleep scientist in the Netherlands and it's very similar to this whole body wet suit and covering that wetsuit are very thin tubes that have water running through them. And in that way, you can select
Actively warm or cool different parts of the body. However, you want and using that same suit as we discussed in the previous episode. You can warm up the surface areas of the body to cool down the core of the body, to fall asleep. But we've since discovered is that, if you then keep cooling the body down, across the night, sleep becomes, both more stable and more plentiful, for example, if
If we take a group of older adults, who often struggle with sleep and also those who suffer from insomnia, both of those groups will have on average around about a fifty percent likelihood of waking up in the middle or the second half of the night. And of course, once they wake up, they will struggle to get back to sleep. But if you actively cool the body, at night, reducing down, that core body temperature, further.
You can decrease that number to less than 5%. And in fact, we've even found that cooling the body in the middle of the night, will boost the size of those deep electrical brain. Waves of deep non-rem sleep that we spoke about in the first episode now, knowingly, or not. You have probably used this proven temperature manipulation to help your own sleep. A
We, for many of us is to draw a hot bath in the evening, and soak the body before bedtime. And you may have thought that your sleep is better after a warm bath or a hot shower. Because when you get out, you're nice and toasty and you fall asleep and you stay asleep better indeed, it's the exact opposite when you've had a warm bath or a shower, all of the blood races to the surface of your skin.
And I get that sort of Rosy cheek look. And as a result with that blood coming to the surface of your skin. When you get out of the bath, your core body, temperature, actually
plummets. And that
is why you fall asleep, faster and stay asleep more easily. In fact, it's so reliable that we call it the warm bath effect in sleep science. And in fact, if you use that method, you can increase the amount of
deep sleep by somewhere between 10 to 15 percent.
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Now, all of the methods that we've spoken about so far regarding temperature or more active interventions, but passive room, temperature also makes a difference here and the long. And short of it. Is that the optimal temperature for sleep at night for the average. Human adult, at least seems to be somewhere between 16 to 18 degrees Celsius or somewhere between
And if I'm doing my mathematics correctly 61 to 65 degrees Fahrenheit of probably got that wrong, but you get a sense of where this optimal sweet spot of temperature is for the ambient room within which you sleep and on average, when adults are slumbering under those temperature conditions, sleep seems to be optimal, but of course, I want to be clear. Everyone will be a little bit different. For example, men will typically
Hotter than women. And by the way, if you're worried about that, very cold bed room, temperature that I described. You can take a hot water bottle to bed and use it for your feet. You can were thick socks if you like that perfectly normal, but cold the ambient temperature must be. And by the way, I will freely admit to using a hot water bottle at night, especially during the winter here. I will leave my windows open year-round and you can do that to us.
Long as it's safe for you to do so, but when I do that, particularly during the winter, is this pretty cold in the bedroom. So I do like to have a hot water bottle. I warm it up, then put it in there about five minutes before, but you don't want to know this about me. This is my personal sleep nonsense. Let me come back to our scientific story. So that's falling asleep that we discussed in the first episode and here we've spoken about staying asleep. So far, the final step we have to discuss of course, is waking up and
Here, temperature makes a difference to what we've discovered. Is that as you move through to those late morning hours of your sleep, particularly, as you start to enter those REM sleep, Rich phases, late in the morning. We see a rise in core brain temperature. And in fact, just as an aside. It's one of the ways that we've been playing around at my sleep center with modifying, REM sleep, by trying to increase temperature to see if we can increase,
Kris REM sleep or dream, sleep and reliably in humans. And people who do animal studies. They will consistently find that it's in the last 30 minutes before people would naturally wake up in the morning, that their body temperature really starts to increase as with breaking up, waking up, can be hard to do for many people, especially if you're not sleeping in synchrony, with your chronotype, which we've spoken about.
Three episodes before. However, one way that we can ease that process of waking up is trying to warm up the ambient temperature of the bedroom in the last 30 minutes before your alarm goes off. So if you have a smart thermostat, try to program it to increase the temperature to around about 21 degrees Celsius or around 70 degrees Fahrenheit in the last 30 minutes before your alarm goes off.
Off. And that is the tale of temperature, which really comes in three parts. We need to warm up to cool down, to get to sleep. And then we need to stay cool to stay asleep. And finally, we need to warm up to wake up. And with that, I will say stay cool tonight. Get hot tomorrow morning. And I will simply say, thank you again, so much for listening and I will
See you next time in the next episode. Take care for now.
