The depth of sleep is generally measured by a decrease in physical activity and a decrease in sensory sensitivity.
Deep sleep is a part of sleep, which accounts for only 25% of the total sleep time. Deep sleep is also called “golden sleep.” People’s nighttime sleep is generally divided into 5 to 6 cycles of recurrence, each sleep cycle is about 60 minutes to 90 minutes.
According to the changes of brain waves, myoelectric waves and eye movements during sleep, the sleep cycle consists of a non-rapid eye movement cycle and a rapid eye movement cycle.
Non-rapid eye movement sleep is divided into light sleep period, light sleep period, middle sleep period and deep sleep period 4, and then enters the “rapid eye movement sleep period”, which is regarded as the end of a sleep cycle, and then continues to start the next sleep cycle.
Studies have shown that the shallow sleep period and light sleep period, which account for about 55% of the total sleep time, have little effect on relieving fatigue, and only the mid-sleeping period, deep sleep period and “rapid eye movement sleep period” that enter deep sleep state. It has a great effect on relieving fatigue.
Because in the deep sleep state, the cerebral cortical cells are in a state of full rest, which is crucial for eliminating fatigue, restoring energy, and immune disease resistance.
However, this deep sleep only accounts for 25% of the total sleep time. Therefore, the evaluation of sleep quality can not only look at time, but more importantly, look at quality.
Is deep sleep the better?
of course not.The deep sleep time required by different people may be quite different. Adults usually spend 15% to 25% of their deep sleep time.
If you sleep for 8 hours, the deep sleep time is between 72 and 120 minutes, which is about 1 to 2 hours.It is worth noting that even if you sleep longer than usual, you can’t increase your deep sleep time.