Spring is here, and with the gradual rise in temperature, many people are caught in the dilemma of “spring sleepiness”, the nights never seem long enough, and colds come in waves. There are many reasons for colds. Many people take off their heavy coats or take a shower immediately after sweating outside, which causes a transient decrease in body temperature and a change in internal conditions, making it easy for germs to take advantage of the environment and induce colds. Spring is a season of wearing a cotton jacket and wearing a skirt to “despise” each other, and a season of sleeping with your arms outside the quilt cold and inside the quilt hot. So some people ask: “Why do you sleep at night with your shoulders and arms outside the quilt will feel cold, easy to catch a cold, but the face is exposed for a long time but not cold?” The head has a number of organs that are very important to the body, and maintaining the normal work of these organs requires a large amount of blood supply, which brings sufficient heat to the face. In addition, from an anatomical point of view, the head is closer to the heart, so it is easier to get sufficient blood supply, so it is more ‘not afraid of cold’ compared to the extremities of the limbs. There are also studies claiming that the face has better cold resistance (ability to adapt to the external environment) due to long-term exposure. Compared to the head, the blood supply to other parts of the body is relatively lagging, so it is understandable that it is easy to catch a cold. In March and April, the temperature has risen, but do not forget to keep warm. Spring is a child’s face, said to change, prematurely take off thick clothes, once the temperature drops it is difficult to adapt, will make the body resistance to decline, and germs will take advantage of the situation, easy to cause a variety of respiratory diseases, we often hear that “spring cover autumn freezing” in the spring cover is very necessary.