You're biking up a hill, pedaling as hard as you can. You're almost there and —
what's this? Your back is all wet and so is your face. Don't sweat it — it's
Your body works best when its temperature is about 98.6ºF (37ºC). When
your body gets hotter than that, your brain
doesn't like it — it wants your body to stay cool and comfortable. So the part
of your brain that controls temperature, called the hypothalamus (say: hi-po-THAL-uh-mus),
sends a message to your body, telling it to sweat.
Then special glands in your skin called — what else? — sweat glands
start making sweat. Sweat is also known as perspiration (say: pur-spuh-RAY-shun),
and it is made almost completely of water, with tiny amounts of other chemicals like
ammonia (say: uh-MOWN-yuh), urea (say: yoo-REE-uh), salts, and sugar. (Ammonia and
urea are left over when your body breaks down protein.)
The sweat leaves your skin through
tiny holes called pores. When the sweat hits the air, the air makes it evaporate (this
means it turns from a liquid to a vapor). As the sweat evaporates off your skin, you
Sweat is a great cooling system, but if you're sweating a lot on a hot day or after
playing hard you could be losing too much water through your skin. Then you need to
put liquid back in your body by drinking plenty of water so you won't get dehydrated
Why Does Sweat Smell?
Sweat isn't just wet — it can be kind of stinky, too. But the next time you
get a whiff of yourself after running around outside and want to blame your sweat
glands, hold on!
Sweat by itself doesn't smell at all. It's the bacteria that live on your skin
that mix with the sweat and give it a stinky smell. And when you reach puberty, special
hormones affect the glands in your armpits — these glands make sweat that can
Luckily, regular washing with soap and water can usually keep stinky sweat under
control. Many teens and adults also find that wearing deodorant
(say: dee-OH-der-ent) or antiperspirant (say: an-tee-PUR-sper-ent) helps.
So don't worry about a little sweat — it's totally normal and everybody sweats.
Sometimes too much sweating can be a sign that there is something wrong in the body,
but this is rare in kids. If you notice more sweat, it's usually just a sign that
it's time to start using a deodorant or antiperspirant. But if you think you have
a sweat problem, talk to your parent or your doctor about it.