Cold chills are caused by an increase in the body temperature set point. Colds are caused by viral infections, at which time the body produces inflammatory factors to fight the viral infection. Inflammatory factors in the fight against infection at the same time, can also act on the hypothalamus thermoregulation center, is the human body temperature set point rise. The human body thermoregulation point rises above the body temperature, the human body will feel cold to stimulate the human body to increase heat production to make the body temperature to reach the thermoregulation point. This situation is similar to the outside temperature drops, the human body feels cold, when the outside temperature drops, the human body temperature receptors feel the outside temperature decrease, although the thermoregulation point does not rise, but the outside temperature is lower than the thermoregulation point, will also produce cold feeling, stimulate the body to accelerate heat production.