Deep sleep is a part of sleep, accounting for only 25% of the whole sleep time. Deep sleep is also called "golden sleep". Deep sleep is the most familiar and fragrant stage in human sleep. At this time, you can't hear any noise outside, and it's hard to be woken up by others. When you wake up, you will feel refreshed. Deep sleep is a child's physical growth and intellectual development; Young people are full of energy; Middle-aged people are physically strong; The guarantee of health and longevity for the elderly. Modern media constantly promote that it is best to sleep from 22: 00 to 23:00, because 12:00- 3: 00 pm is a deep sleep period. As long as you sleep well in these three hours, you will be full of energy all day. If you miss it, it will have a very bad effect on your body.