When you sleep, your breathing becomes slower and your blood pressure drops. Furthermore, the heart rate decreases. The body at rest, in fact, requires less cardiovascular effort. During the night, then, the body temperature also tends to lower. Before falling asleep, it begins to decrease and even drops by more than two degrees during the night. During the day, the body temperature is around 36.5°C: lower in the morning, it rises in the afternoon up to 37°C.
Because the temperature drops at night
The circadian clock, which is a group of cells located in the hypothalamus of the brain, is connected to the eyes. The sleep and wake cycle is regulated precisely by communications between the eyes and the brain. And it is known as circadian rhythm. During the day, your eyes detect natural light and tell your brain that you should be awake. This condition stimulates the production of cortisol, which is known as the hormone and transmits feelings of alertness. Thus, your internal temperature also remains constant. However, when natural light fails, the brain releases melatonin, which serves to relax the body. This causes the body temperature to decrease, starting two hours before falling asleep.
Because the temperature on the contrary can rise (but it is not normal)
Sleeping in an insufficiently ventilated room leads to an excessive perception of heat and consequent sweating which, especially in summer, is harmful. Ventilating rooms before sleeping is always recommended. If possible, sleep with the door open. Wear "fresh" clothing, preferring natural fibers (especially cotton) to synthetic ones. Better if loose and comfortable. Nighttime temperatures may rise as a side effect of certain medications or in cases of illness and infections.
So what is the optimal body temperature at night?
Regardless of the season, an external temperature that does not exceed 20°C is the best one for resting well. Sleeping in a cool environment, both in summer and winter, promotes quality rest. Nighttime body temperature should never exceed the "classic" 36.5°C. A lower temperature is always recommended, as long as it does not fall below 35°C. As clinical studies demonstrate, various symptoms of insomnia have been associated with body temperature abnormalities. There is therefore a direct relationship between insomnia and an altered temperature