Why Do We Sweat?

Words to Know

Sweat glands

Tiny factories in your skin that make sweat

You have millions of sweat glands all over your body!

Evaporate

When a liquid turns into invisible gas and floats away

When sweat evaporates, it takes heat with it to cool you down.

Bacteria

Super tiny living things you can't see without a microscope

Bacteria on your skin eat sweat and make the stinky smell.

Evaporative cooling

Getting cooler when water turns to gas on your skin

Sweating is your body's way of doing evaporative cooling.

Check What You Learned

Fun Facts

• Sweat is produced by eccrine sweat glands, which are located all over the body. There are approximately 2–4 million sweat glands in the human body.

  Source: American Academy of Dermatology

• Sweat is composed of about 99% water, with small amounts of salt, proteins, and oils.

  Source: Cleveland Clinic

• Evaporation of sweat from the skin surface cools the body — this is called evaporative cooling. The heat of vaporization of water means energy (heat) is absorbed when liquid turns to gas.

  Source: NIH MedlinePlus

• Sweat itself is odorless. Body odor is caused by bacteria on the skin breaking down proteins and lipids in sweat produced by apocrine glands (located mainly in armpits and groin).

  Source: Mayo Clinic

• Horses are one of the few animals that sweat extensively like humans to cool down. Dogs primarily cool themselves by panting, not sweating through skin.

  Source: Smithsonian Magazine

• The human body can produce up to 1.5–2 liters of sweat per hour during intense exercise in hot conditions.

  Source: American Council on Exercise