Thermal Equilibrium
Thermal equilibrium is when the body is losing the same amount of heat that it is producing, hence body temperature stays constant over time.
The body reaches thermal equilibrium with its surrounding environment when its body temperature matches the temperature of the surrounding air, water or ground. This would mean that there is zero net heat exchange with the surrounding environment. To maintain thermal equilibrium with its surroundings, and therefore maintain internal thermal homeostasis, the body can alter the level and type of heat exchange with the environment. The body can alter the circulatory system, to increase or decrease heat exchange with the environment. Internal temperature can be increased through a method known as metabolic heat production, whereas it can be reduced through a process called evaporative heat loss.