Sleeping is asked by the university! As the saying goes, going to bed early and getting up early is good for your health. There is only one concept, no quantification and no meaning. The key to sleep quality lies in deep sleep. It can be said that only 2~3 hours of sleep is enough. Usually 0 to 3 o'clock is the time for deep sleep, but you can't go into deep sleep as soon as you fall asleep. There is a transition period, usually 1~ 1.5 hours! Conversely, it is best to go to bed from 22: 30 to 23: 00 to prepare for a deep sleep! The recommended work and rest time is: 22: 00 ~ 23: 00 in summer-> 6: 00 ~ 7: 00 in sleep-> 21:30 ~ 22: 30 in winter-> Fall asleep at 6:30-7:30-> At noon, people's alertness is declining. At this time, taking a nap helps to restore the spirit and is good for work, study and health. The optimal sleep time of all ages is as follows: newborn 20 hours, preschool children 14- 15 hours, pupils 12 hours, middle school students 10 hours, college students 9 hours, adults 8 hours and the elderly 6-7 hours.