Your body's fire department.

Fi-i-i-re! When it's warm outdoors or you've been exercising hard, you might say that you feel hot enough to "burn up." That's when your body calls on its own special "fire department" to bring the heat down to a safe temperature level. Here's how it works.

Deep inside your skin are many tiny, coiled tubes that open onto the surface of your skin. These tubes are called sweat glands.

When your body is at a comfortable 98.6[degrees] F, your sweat glands have nothing to do.

But when your brain discovers that your body's temperature is climbing above its comfort level, it lets your sweat glands know to start pumping out water. This water is called sweat.

As air blows over your wet skin, the sweat evaporates, and your skin cools off. This lowers your body's temperature.

Without enough water in your body, your sweat glands can't work properly.

A water shortage will cause your body temperature to keep rising, which can be quite dangerous. That's why it's important to drink plenty of liquids--water is best--when you feel hot or when you're exercising.

No Sweat!

Ever pet a sweaty dog? No chance! That's because dogs, like many animals, have no sweat glands. Instead, a dog has to pant to keep cool. Air flows over its tongue and evaporates the saliva on it. This eventually lowers the dog's body temperature.