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Medically reviewed by: Melanie L. Pitone, MD

What Is Dehydration?

When it's hot outside and you've been sweating, you get thirsty. Why? Thirst can be a sign of dehydration (say: dee-hye-DRAY-shun). Dehydration means that your body doesn't have enough water in it to keep it working right.

A person gets water by drinking and eating. You lose water when you sweat, urinate (pee), have diarrhea, or throw up. You even lose a little water when you breathe.

Our bodies need water to work properly. Usually, you can make up for the water you lose — like when you come in from outside and have a long, cool drink of water. If you don't replace the water your body has lost, you might start feeling sick. And if you go too long without the water you need, you can become very ill and might need to go to the hospital.

Why Am I Dehydrated?

Many times kids get dehydrated when they're playing hard and having fun. Have you ever gotten really sweaty and red-faced when you've been playing? This often happens when it's hot outside, but it can happen indoors, too, like if you're practicing basketball in a gym.

Kids also can get dehydrated when they're sick. If you have a stomach virus, you might throw up or have diarrhea (say: dye-uh-REE-uh) or both. On top of that, you probably don't feel very much like eating or drinking.

If you have a sore throat, you might find it hard to swallow food or drink. And if you have a fever, you can lose fluids because water evaporates from your skin in an attempt to cool your body down. That's why your mom or dad tells you to drink a lot of fluids when you're sick.

What Are the Signs of Dehydration?

Being thirsty is the top clue. Here are some other signs that a person might be dehydrated:

  • feeling lightheaded, dizzy, or tired
  • rapid heartbeat
  • dry lips and mouth

Another sign of dehydration is not peeing as much or having dark or strong-smelling pee (pee usually is a pale yellow color).

What Should I Do?

If you can, try not to get dehydrated in the first place. If you're going to be going outside, it's a good idea to drink water before, during, and after you play, especially if it's hot. Dehydration can happen along with heat-related illnesses, such as heat exhaustion and heat stroke.

So do you have to drink eight glasses of water a day? No, but you do need to drink enough to satisfy your thirst, and maybe a little extra if you're going to be exercising. Also, it's smart to dress in cool clothes and take breaks indoors or at least in the shade.

If you're sick, keep taking small sips of drinks like water or diluted juice, even if you're not that thirsty or hungry. Eating an ice pop is a great way to get fluids. Other foods, such as fruits and vegetables, contain water too, but if your stomach is not feeling well you might not be ready for them.

Limit soda and other sugary drinks, such as fruit punches, lemonades, and iced teas. These drinks have a lot of sugar that your body doesn't need. Some also contain caffeine, which can make you pee more a lot. In other words, it tells your body to get rid of fluids. And as you now know, that's the opposite of what you need to do if you're dehydrated!

Do I Need a Doctor?

Some cases of dehydration can be handled at home. But sometimes, that isn't enough to get a kid feeling better. A kid may need to go to the doctor or emergency room if they have a heat-related illness or a virus with vomiting or diarrhea that just won't quit.

At the hospital, the good news is that an intravenous (say: in-truh-VEE-nus) (IV) line can get fluids into your body fast. An IV line is a special tube (like a very thin straw) that goes right into your vein, so the liquid goes right to where your body needs it most. It may pinch a little when the nurse is inserting it, but it will help you feel much better.

Medically reviewed by: Melanie L. Pitone, MD
Date reviewed: June 2023