The thermoregulatory system of homeotherms has an inherent ability to hold core body temperature within a small variation of a set point. Excursions above and below the set point can cause compromised body function, injury, and even death may occur.
Operation of the thermoregulatory system is based on a complex, nonlinear network of feedback control signals and responses to adjust the thermal resistance between the body core and the environment and to modulate the rate and distribution of internal energy generation. The operation of the thermoregulatory system is remarkably efficient over a broad spectrum of physiological states and environmental conditions.
In certain circumstances, however, the thermoregulatory system is unable to maintain the core temperature within the set operational range, or there may be therapeutic or prophylactic reasons to override the system to maintain a reduced core body temperature.