Why is winter solstice a good season for tonic?

The winter solstice is the shortest day and the longest night in a year. There is a saying in the Book of Changes that "the sun is born on the solstice of winter". Specifically, when the solar term runs into winter, the cathode is Yang. At this time, the yang in the human body is strong, and it is the easiest to absorb foreign nutrition and play its nourishing role, which fully shows that it is most appropriate to take supplements around this day.

The first sentence at the beginning of Jiuyin Zhenjing in Legend of the Condor Heroes is: Heaven can make up for the deficiency. This sentence comes from China's simple materialistic dialectical thought of yin and yang, which explains the principle and method of tonic. The reason for tonic in winter is that TCM health care attaches great importance to conforming to the objective law of the change of Yin and Yang in four seasons and maintaining the relative balance between Yin and Yang in human body and Yin and Yang in four seasons in nature, that is, "Yin and Yang are the secret, and God is the rule". If yin and yang prevail, it will lead to disease. Summer is sunny, and autumn and winter are cloudy. Winter is the coldest season of the year. Because nature is characterized by yin exuberance and yang decline, vegetation withers, and everything is hidden, the biochemical metabolism and functional activities closely related to nature of the human body are correspondingly weakened, the essence of the human body is restrained, and the skin on the body surface is dense. At this time, tonic is the easiest to absorb and store, thus achieving the goal of getting twice the result with half the effort. After three seasons of activities in spring, long summer and autumn harvest, human physical strength is exhausted, and liver function, yin and blood are "overdrawn". In winter, it is especially necessary to adjust and supplement in time. The solstice in winter belongs to the yin in the yin, and the yin cold is the most abundant. Coupled with frozen snow, cold wind and the fragility of human yang, it is bound to make yin more abundant, yang more declining, human disease resistance reduced, and old diseases are the most serious.