Keep Your Cool - Human Body

Even when you are resting, your body generates so much heat that you are comfortable only when the air is slightly cooler than you are.

When you are working hard, your muscles can generate as much heat as a 2 kW heater.

Your body loses heat as you breathe in cool air and breathe out warm air. Your body also loses heat by giving it off from your skin.

The body's temperature control is the tiny hypothalamus in the brain.

Temperature sensors in the skin,in the body's core, and in the blood by the hypothalamus tell the hypothalamus how hot or cold your body is.

If it is too hot, the hypothalamus sends signals to your skin telling it to sweat more. Signals also tell blood vessels in the skin to widen - this increases the blood flow, increasing the heat loss from your blood.

If it is too cold, the hypothalamus sends signals to "If the skin to cut back skin blood flow, as well as signals to tell the muscles to generate heat by shivering.

If it is too cold, the hypothalamus may also stimulate the thyroid gland to send out hormones to make your cells burn energy faster and so make more heat.