Thermoregulation is the is the ability that humans and other mammalian species have of internally regulating their body temperature.
For mammals it is imperative to keep the body temperature within certain boundaries. Body temperature in excess of, or below, said boundaries for a lengthy period of time can result in injury or death. Temperatures above or below these boundaries can be caused by disease or infection (fever) or long-term exposure to the elements (hypothermia and hyperthermia). The body uses many different mechanisms for thermoregulation; perspiration, increases/decreases in heart rate, restriction of blood flow, and shivering.