Hi there, it's Matt Walker here, and welcome back to the podcast. Now. I'm sure you've heard of that phrase where people will tell you cold hands, warm heart. So, the saying goes in truth. I don't know of any scientific data to back that up. But there is scientific truth. However, in the statement warm feet, good sleep and we'll get to that.
Because for the next two episodes were talking all about temperature, how your own temperature and specifically the temperature of different parts of you and the temperature of your bedroom can change, how well or how poorly you sleep at night. What we discovered many years ago. Was that your brain and your body need to drop their core temperature by about 1 degree Celsius or about 2 to 3 degrees Fahrenheit.
In order for you to fall asleep and for you to stay asleep across the night and this is the reason why you will always find it easier to fall asleep in a room. That's too cold than too hot because the room that's too cold. Is at least taking you in the right temperature. Direction for good sleep at night. And we've seen this time and time again so I can bring you into my sleep center and upon arrival. I
I'll insert a rectal probe so that I know exactly what's happening with your core body temperature. You may think that that sounds like no fun for you, but I can also say that it is far from the most desirable thing to insert as a scientist. That the things that we do for research. Let's just say that the two of us will have slightly less dignity at the end of that procedure.
And after inserting the rectal probe, I will then remove all sense of time. There will be no clocks, no windows, no phone, no computers. And then I'll simply ask you to go to bed at whatever time, you wish, whenever you feel most sleepy. And even though you have no idea of what your core body temperature is sure enough. You will say that you hit your
He sleepiness right at the steepest decline in your core body temperature that I'm measuring with the rectal probe. But let's double click on this temperature thing and delve a little deeper because it's even more nuanced than this one. Essential way for you to drop your core body. Temperature is to ironically warm up your extremities, specifically your hands and your feet.
Now, I know that that sounds counterintuitive. But it's one of the key ways that your body regulates temperature and some wonderful and bizarre experiments made us. Realize this fact, for example, the scientists have found that if they gently warmed the paws of rats, so that they encourage the blood to rise, to the surface of the skin of those Paws away from the core of the body. Those poor.
Wars would emit heat away from the center of the body and it would drop their core body temperature rapidly. And as a result, the rat drifted off to sleep far. Faster than was otherwise normal. And I just love the idea by the way of scientists sort of cuddling these rats in some kind of luxurious cotton wool and gently warming their paws. Fantastic
image.
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Of vitamin D Supply with your order as well. Anyway, thanks so much for listening to this segment. And now let's get back to the podcast, my colleague, and very dear friend in the Netherlands Professor, Zeus and summer and has actually conducted an even more elegant study. But in humans, what he constructed was a whole body temperature sleep.
In
suit and it's not dissimilar in appearance by the way to a wetsuit now water was involved but nobody got wet. Thankfully because lining this special suit was a whole intricate network of thin tubes or veins essentially and crisscrossing the body almost like a detailed road map, covering all major districts of the body, the arms, the hands, and the feet, he could then X.
Exquisitely and selectively control, the warming of different parts of the body. All the while the participants were laying quietly in bed asleep and had no sense of what was going on, absolute genius. And in his first series of studies, he selectively warmed, the feet and the Hands by just a small amount only by about one degree Fahrenheit, or less than point five.
Celsius but what that warming of the hands and the feet caused was arising of the blood to the surface of the skin. And essentially what he was doing, was Charming the heat out of the core of the body of these participants were it had been trapped and as he warmed the extremities of the body, the core temperature dropped significantly. And the upshot was that he had these healthy participants.
Issa pants, falling asleep, 20% faster than was normal. And we've now seen similar results in groups, that we know, typically struggle with sleep, both older adults, and also patients with clinical insomnia. And if you manipulate temperature in the same way, the older adults will fall asleep, 18 percent faster than is normal. And the insomnia, patients will fall asleep. A full 25%. Faster than is normal.
So, that's the process of falling asleep. And how temperature is involved in, how we fall asleep. In the next episode. We're going to focus on staying asleep. And then finally on waking up and how temperature can change both of these things. But for now, I will simply say thanks once again for tuning into the episodes. I know I'm gonna keep saying tuning in. I know it's that you download and just listen but
Thanks again for tuning into these episodes, and thanks also for subscribing to the podcast and for all of the kind and very supportive reviews that people have put out there. Please don't feel any need to do that. But if you do feel moved, goodness me, it makes such a difference to me. So thank you again. And I will see you in the next episode where we take on temperature part
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