Everyone’s biological clock is different, so for individuals, the time to sleep is different from person to person. Sleeping from 10:00 pm to 6:00 am each night is appropriate, but usually going to bed past 11:00 pm is considered staying up late. The best time for the body to rest and repair is between 11pm and 3am. Sleep during this time can promote the growth and development of children and adolescents, and promote the rest and recovery of the adult organism. If you stay up late for a long time, you may experience mental depression, fatigue and drowsiness, memory loss during the day, which also leads to a decrease in body resistance and susceptibility to colds and other symptoms. In addition, stay up late is not conducive to skin recuperation, easy to lead to aging, acne, freckles, dull complexion. There can also be hypertension, diabetes, coronary artery spasm, leading to myocardial infarction, cerebrovascular accidents and other diseases. Therefore, the time to go to sleep according to personal work, study time deployment, it is recommended that regular rest, avoid staying up late, it is best not to go to bed more than 11:00. Ensure sufficient sleep, can effectively relieve physical fatigue, relaxed mood.