Why are there so many diseases at the turn of winter and spring?

The north wind often blows in winter. Stimulated by the winter climate with very dry air, short sunshine time and high atmospheric pressure, the physiological functions of human organs and systems must be contracted and adjusted accordingly to reduce heat consumption and ensure the necessary heat and nutrition supply for the body to resist cold and snow. On the contrary, under the influence of spring climate with long sunshine, increasing sunshine and rapidly rising temperature, the physiological function and metabolic rate of the body will be enhanced, and the biological clock rhythm will be greatly accelerated than that in winter. This is because sunlight and temperature are the main "regulators" of biological rhythm in human body. When winter and spring alternate, sometimes it presents winter climate characteristics, sometimes it presents spring climate scenery, which is changeable repeatedly, and it is warm and cold at first. Therefore, the physiological function of the human body is to contract in winter and move more in spring, which needs to be adjusted repeatedly. Once the adjustment is not timely or repeated, it is easy to cause some diseases. In addition, at the turn of winter and spring, some other diseases will appear in some organs and tissues of the human body, such as arthritis, cardiovascular and cerebrovascular accidents, neuropsychiatric dysfunction and so on. Old and frail people and children are more susceptible to various diseases. The same is true for some elderly people or critically ill patients who have a peak of death and illness in winter and spring alternate seasons. In order to nip in the bud, at the turn of winter and spring, people who are frail, very old and have young children should go out as far as possible, go to public places and crowded places, keep the indoor temperature relatively stable, and prevent the influence of external climate on their health and the invasion of germs.