Heat Exchange with the Environment

Abstract

Under equilibrium heat flow conditions the amount of heat formed in the body per unit time is equal to the amount given off from the body surface, the temperature field within the body remaining constant over that time. For homeothermal organisms however this is true only for integrated values over longer periods, while the instantaneous values are in equilibrium only in most unusual circumstances. Usually the heat content of the body fluctuates widely as a result of accumulation and discharge of heat and of changes in the temperature field. The heat content of individual humans (specific heat of the body = 0.83 cal g⁻¹ °C⁻¹) may change by as much as several hundred kcal.