Andrew Huberman· PhD
Or if you're into the sauna or it's even like some people, including myself, if I take a hot shower or sit in a hot tub or a sauna late at night, well then I get a compensatory decrease in body temperature and I sleep great provided I hydrate well enough, 'cause that can be kind of a dehydrating thing to sit in hot, hot conditions. But if I do the sauna early in the day, unless I exercise immediately afterward then I tend to get the temperature drop, which makes sense because when you get in the sauna, you're get vasodilation. You throw off a lot of heat and then you generally get a compensatory drop in temperature. If you do that early in the day, that's right about the time that temperature is trying to entrain the circadian clocks of your body.