Usually the best time for human body to sleep is from 23:00 at night to 7:00 in the morning of the second day, 8 hours of sleep is the best time for human body to sleep. The best sleep time according to the human body in the deep sleep phase to more than 4 hours, light sleep phase to less than 3 hours, but people from sleep to enter the deep sleep phase usually takes about 3 hours, so at 23 points to sleep, in the morning at 2-3 points into the deep sleep phase of the whole day. Entering the deep sleep phase at 2-3 a.m. has the greatest effect on body protection, enhancing the protective effect of cardiovascular endothelial cells and gastrointestinal tract balance and barrier capacity, which has a good repair and improvement effect on cardiovascular endothelium and cardiovascular blood supply. In addition, entering deep sleep time at 2-3 am can eliminate fatigue, increase human memory, reduce plant nerve dysfunction, etc.