Many medical investigations have found that the frequent occurrence of diseases in modern people is closely related to irregular work and rest. Sleeping at night, getting up in the morning, and disordered work and rest have become factors that can't be ignored affecting modern people's health. According to the ancient theory of health preservation, all human activities should be constantly adjusted with the changes of nature, which is beneficial to health. Huangdi Neijing is a famous classic of TCM health preserving, which has a scientific discussion on people's work and rest in different seasons and has important guiding significance for modern people's health preserving.

In spring and March, people lie down at night and get up early, and travel widely in the Yellow Emperor's Sutra. It is pointed out that spring is the season when human yang rises. In order not to interfere with the operation of yang, people should sleep late appropriately, so as not to inhibit the operation of yang by going to bed early. In the spring morning, the yang of nature is gradually rising, and the human body should conform to this natural law. It is necessary to get up early and do some relaxing activities, such as walking in the yard, to promote the rise of yang, which is beneficial to health. But no matter what season, don't go to bed too late, and go to bed before 1 1 in spring night to avoid damaging the liver.

In Xia San month, people lie down at night and get up early, which is the most vigorous time of human yang in summer. Huangdi Neijing holds that people should go to bed late and get up early, and receive proper sunlight. In summer, they still have to go to sleep before 1 1 in the evening, and get up earlier than in spring, and even get up at dawn to exercise around 5 am. This kind of work and rest in summer can promote various functions of the body with the help of the operation of yang, and is also conducive to the rapid excretion of garbage metabolized by the body, which is of great benefit to the health of the year.

In autumn and March, people should go to bed early and get up early, which is the season of convergence. The yang in nature begins to recover inward, and the human body should follow this rule. Therefore, people should pay attention to going to bed early in autumn, and it is best to fall asleep around 9 pm, which is conducive to the convergence of sun be the spirit. Although there is still a lot of yang in nature at this time, the general trend is in a circular state, so people have to get up early, but at this time they have to get up early in sync with the creatures in nature, and the Yellow Emperor's internal medicine says that they are all with chickens.

In winter and March, when you go to bed early and get up late, you must stay in the sun. Winter is the season of collection. At this time, the yin in nature is heavy, and the yang is hidden inside. The human body should follow this rule and go to bed early, preferably around 8 pm. Modern people are used to nightlife and sleep late in winter, so that the body's yang is constantly diverging and not collecting. Spring will rise and weaken due to insufficient yang, leading to various diseases. In winter morning, before the sun comes out, the yin is very heavy, which is easy to hurt the yang, so people in this season should get up late and wait until the sun comes out, which is conducive to protecting the yang and promoting health.