The theory of "four qi regulating the spirit" is a supplement to the simple theory of "yin and yang are regular, and daily life is regular", saying that our body should adapt to the changes of the four seasons, adjust according to the laws of the four seasons, and keep healthy through prevention in advance. If you don't pay attention to nursed back to health at ordinary times, the root of the disease will be deep and it will be difficult to adjust later. Therefore, health preservation is not something that only the elderly should do, but should be regarded as a habit, a normal state, and adjust one's body and state with the seasons to keep healthy.