in sleep, people lose thermoregulation from involuntary nerve system. Especially during the REM sleep. That is to say the body will not make effort to keep up body temperature if all of sudden the ambient temp drops - the temp when you just get into sleep might be warm but later it may drop even from running fans - the arousal from low body temp is also reduced during sleep and leads to very late response if any to wake up. That's why parent will tuck their infants well even when it's warm. Babies usually have 50% REM sleep of all.
【在 l******a 的大作中提到】 : : in sleep, people lose thermoregulation from involuntary nerve system. : Especially during the REM sleep. That is to say the body will not make : effort to keep up body temperature if all of sudden the ambient temp : drops - the temp when you just get into sleep might be warm but later : it may drop even from running fans - the arousal from low body temp is also : reduced during sleep and leads to very late response if any to wake up. : That's why parent will tuck their infants well even when it's warm. : Babies usually have 50% REM sleep of all.