1. It is able to eliminate fatigue and restore physical strength. During sleep, the basal metabolic rate decreases, so it can restore physical strength; 2, is to protect the brain and restore energy. Oxygen consumption of the brain is greatly reduced in the sleep state, which is conducive to brain cell energy storage; 3, is to enhance immunity. Sleep can enhance the body’s ability to produce antibodies, thereby enhancing the body’s resistance, modern medicine often sleep as a means of treatment; 4, is to delay aging and promote longevity. Research data show that long-lived old people have good sleep habits, sleep can ensure the long life; 5, is to protect mental health. Sleep is very important to maintain normal mental activities, lack of sleep will cause irritability, agitation, mental depression, etc.; 6, is beneficial to skin beauty. Sleep can accelerate skin regeneration and protect the skin.　　So sleep is an important physiological process of the human body, it has a very important role in human energy, physical recovery and growth and development.