How is a constant body temperature maintained and heat production and heat transfer balanced?

Constant body temperature is a property of warm-blooded animals. Regardless of the environment, our temperature is constant and this ensures a stable existence in any natural conditions – the equator or the extreme north. Heat transfer is regulated through the narrowing and expansion of the skin vessels. When expanding, a person gives off heat to the environment, and when narrowing, the return decreases. Therefore, in the cold we turn pale, and in the heat we blush. Also, sweat glands play an important role: when the air temperature rises, we can increase the production of sweat and with it give off heat, cooling down. When we freeze, we generate energy, for example, by muscular work (shivering in the cold) and by breaking down the reserves of subcutaneous fat.