There are usually four main reasons for being cold. 1, the initial stage of infection, often due to viral and bacterial colds and infections, the body initiates an immune response, when the body will produce antigenic antibody complexes, so that the discharge of the pathogenic microorganisms that invade the body, will lead to a downward shift in body temperature, hypothalamus, central nervous system adjustment point, body temperature drop, cold symptoms. 2, cold body is also related to low basal metabolic rate, often The endocrine metabolic diseases, such as hypothyroidism, hypoadrenocorticism will also lead to hypothermia, cold body. 3, and finally, such as infectious shock, hypovolemic shock, distributive shock, cardiogenic shock leading to a transient blood supply, oxygen supply is insufficient, there will be pale and wet cold, low peripheral skin temperature, cold, fine pulse rate, blood pressure can not be measured and other shock conditions.