Sleep's Critical Role in Everything Humans Do
Your body, on the other hand, slows down
In stark contrast to the brain’s activity during sleep, the body definitely slows down in order to accommodate rest. Breathing slows, as well as muscle activity. The liver switches from actively detoxing during the day, to synthesizing and rebuilding substances in anticipation for the next day. Blood pressure is also lowered due to what is called ‘nocturnal dipping’, which is a term for total-body relaxation. Regular individuals might see a drop of 4 to 5 points in their blood pressure, while those who exercise regularly could experience even better results, with a decrease in about 5 to 7 points of their blood pressure during sleep.
Body temperature also decreases during sleep by about 2 degrees, which is why sleeping in a cool room is recommended for a good night’s sleep, since a chilly room temperature mimics what the body does naturally by itself: cool off by a few degrees. Interestingly enough, the boy loses its capacity for thermoregulation during sleep, which means that, even with temperatures that would make a person shiver during the day, the body can usually just snooze through. On this last topic, Veasey stated that "We have no earthly idea why that happens."