For example, in a year, from winter solstice to spring and summer, the yin disappears and the yang grows, and the climate gradually turns warm and hot from cold pity; From summer to autumn and winter, the yang disappears and the yin grows, and the climate gradually turns from hot to cold. But generally speaking, the climate change of the four seasons is in a relative dynamic balance. If the physiological dynamic balance of human body is unbalanced, and one aspect of Yin and Yang is high or low, there will be pathological changes, such as cold syndrome, heat syndrome, excess syndrome and deficiency syndrome.