Why do people need sleep?

        This is an old and fresh topic with no satisfactory answer yet. In the early days, it was considered to be a kind of pause in consciousness, and later it was regarded as a temporary mental rest, similar to animal dormancy, which is a kind of "disconnection and inactivation" of nerve cells. Since the electrophysiological technology, people It gradually unveiled its "veil of mystery."

　　 It turns out that human sleep is not a passive and static process as originally thought, it is only caused by the continuous entry of various stimuli into the brain during fatigue or awakening. Polysomnography found that people’s sleep is a periodic and regular active physiological process in different phases.

        According to the characteristics of the described electroencephalogram, eye movement and electromyography, it can be roughly divided into rapid eye Dynamic sleep (abbreviated as REM) and non-rapid eye sleep (abbreviated as NREM).

        In the REM sleep stage, rapid and irregular eye movement can be found, breathing and heart rate increase, blood pressure rises, and muscle tone decreases; non-rapid eye movement sleep can be further divided into 1, 2, 3 4. During the four periods, regular and characteristic brain electrical activities such as sleep spindle and high-amplitude slower brain electrical activities can be seen during the period. And a REM sleep and non-REM sleep constitute a sleep cycle, about 60-90 minutes, about 4-7 such cycles in a night, young people sleep overnight, REM sleep is about It accounts for 20%-25%, and non-rapid eye movement sleep accounts for about 75%-80%.

        Further studies have found that in the REM sleep stage, continuous sleep produces short periodic awakenings, which is beneficial to the body to remain alert to changes in the surrounding environment, and to increase protein synthesis in infants and young children, and it is beneficial to maintain neurological function in adults. Complete, participate in the transformation and consolidation of memory. In the non-REM sleep stage, it is found that the energy consumption of the body is reduced, and the secretion of various hormones of the pituitary increases, and the secretion of growth hormone reaches the peak in the fourth stage, so it can eliminate the body's fatigue and restore physical strength.

In short, sleep is very important to the physical and psychological health of the human body. People should arrange their lives scientifically, have regular schedules, have good sleep, and enjoy a happy life.