The reason why Xu Wenbing opposes winter swimming is that it violates the principle of winter storage. According to relevant information, Xu Wenbing, a famous master of modern Chinese medicine, opposed it. He believes that winter swimming violates the principle of winter storage. People who swim in winter must have strong innate endowment and sufficient kidney essence, otherwise it will do harm to their health. Winter swimming refers to swimming in outdoor waters (including natural waters such as rivers, lakes and seas and artificial waters such as reservoirs) at natural water temperature in winter.