How temperature and sleep are connected
You have probably already noticed that it is impossible to fall asleep if you are too cold or too hot. This makes developmental sense, to ensure your own survival. Basically our body core is well shielded from the outside world, so that even with temperature changes the body core temperature does not change immediately. Our body compensates for this. However, this does not work indefinitely, at a certain point the body has to drastically restrict its functions to ensure survival. Sensors in the skin give permanent feedback on how high the outside temperature is. As a result, the brain regulates the degree of activation. Because if it's too cold or too hot, it's better not to sleep.
As mammals, we humans are "equally warm". This means that we are able to regulate our body temperature ourselves, even when we are exposed to changing temperatures. All warm beings have evolved from warm creatures, whose heat balance is strongly dependent on external factors. Thus reptiles do not lie in the sun for their complexion, but because they need the heat gained from it for their activities. In return, they can only sleep when their whole body has cooled down.
In us mammals this is a little more complex. Our body core temperature also falls when we sleep, but our skin temperature rises in parallel.
If we look at these biological backgrounds, we find it is easiest to fall asleep when our body core is nice and cool. The extremities on the surface of the skin are warmer because the high number of blood vessels in these regions allows heat to dissipate. More blood circulation in the feet and hands means more heat dissipation and therefore a cooler body core, which ultimately leads to better sleep.
Through certain behaviours you can create the ideal temperature environment for your body and a quick fall asleep:
- Before going to sleep, raise the skin temperature by taking a hot shower, footbath, warm clothes or socks, for example
- Avoid extreme ambient temperatures in the bedroom, as these would start an activation that is not conducive to sleep. Low temperatures in the bedroom, on the other hand, can promote the desired cooling via the skin and help you fall asleep quickly.
You can find further information on this topic here: https://blog.humanos.me/how-to-fall-asleep-faster-warm-feet-quick-to-sleep/