Deliberate cold exposure timing should consider baseline body temperature circadian rhythm to optimize states or avoid interfering with sleep.

“That background or what we call baseline circadian rhythm in core body temperature is important to remember because it helps us frame both the effects of deliberate cold exposure and helps us frame when you might want to use deliberate cold exposure in order to access specific states. It also points to times within the 24 hour cycle when you might want to avoid using deliberate cold exposure, if your primary goal is to get to sleep.”

“cold exposure late in the evening will start to increase your body temperature again. And that can make it hard for some people to fall asleep.”

“However, if you have trouble sleeping, I would recommend doing the cold exposure early in the day to match that natural heating, that natural increase in body temperature that occurs across the 24-hour so-called circadian rhythm.”

“I would hypothesize that it also might lead to some of the um subjectively reported improvements in sleep because in order to fall asleep you need your core body temperature to drop by about 1 to 3° yes”

“I could imagine that doing deliberate cold exposure at different times um just by way of convenience or by way of intention could be very beneficial because my body temp is going to be quite a bit warmer at one time of day versus another and in that way keeping the system tuned”