The first principle of health preservation in Huangdi Neijing is: "Four seasons are suitable for cold and summer." Only when people adapt to the changes of the four seasons can they be beneficial to health. The characteristics of all the year round: "Spring is born and summer is long. It is common to harvest in autumn and store in winter, and people should also deal with it."

Chinese medicine pays attention to the unity of man and nature. Work at sunrise and rest at sunset. You should go to bed early and get up early.

Chinese medicine believes that "nourishing the kidney" is particularly nourishing. Minute hour: 23: 00 ~ 1: 00. So, go to bed before 1 1 at night.

Although Huangdi Neijing requires sleeping late in spring and summer and getting up early in autumn and winter, Chinese medicine is dialectical. What's early and what's late is relative. The general principle is that you can go to bed before midnight all year round.