Sweat uses evaporative cooling to maintain body temperature. As liquids evaporate, they shed molecules into the air. The liquid changes into a gas, drawing heat from the liquid. The process draws heat from the body. Evaporation also cools the remaining liquid because faster-moving hot molecules are more likely to escape into the air, according to HowStuffworks.
Reference.com states that the hypothalamus is responsible for controlling sweating. There are thermosensitive neurons in both its preoptic and anterior regions. Temperature receptors on the skin provide input to the hypothalamus; however, the process is primarily due to an increase in an individual's core temperature. While sweating reduces the core temperature, evaporation decreases the surface temperatures.
The body also produces sweat in response to pain, fear, lack of oxygen and low blood sugar, according to About.com. This cold sweat is an indicator of another problem within the body and stops once the problem is rectified. Cold sweats are a part of the body's fight or flight response and are often an indicator of shock. If an individual is experiencing shock, the Mayo Clinic recommends calling for emergency medical assistance. The person should be made to lie down with his feet elevated and wrapped in a blanket to be kept warm. A person suffering from shock should never be given anything by mouth.