Dehydration

Did you know that about two-thirds of your body is made up of water? That’s a lot! Even though it’s normal to lose some water every day, there may be times that you lose too much and become dehydrated. Read on for more information about dehydration.

What is dehydration?

Dehydration is the medical term for the condition that occurs when someone’s body loses more water than they’re taking in. When the body doesn’t have enough water, it can’t work properly. Mild dehydration doesn’t usually cause problems, but if it isn’t treated it can become severe dehydration, which is a medical emergency.

What causes dehydration?

Your body naturally loses some water every day, through urination (peeing), bowel movements, and sweating. However, factors that may cause you to lose too much water include:

• Vomiting
• Diarrhea
• High fever
• Extreme sweating from intense physical activity or hot weather
• Certain medicines such as “diuretics” work to remove extra fluid in the body

You can also become dehydrated from not drinking enough water. For example, if you have a sore throat or you feel sick, you might not take in as much fluid as you should. Especially if you’re sick, it’s important to stay hydrated.

How do I know if I’m dehydrated?

Did you know that when you feel thirsty you’re actually already dehydrated? Dehydration usually starts with mild symptoms that get worse unless fluid/water is replaced. Other symptoms of dehydration include:

• Urinating less often than usual, or passing urine that looks dark yellow or brown
• Having a dry, sticky mouth or cracked lips
• Feeling tired
• Feeling dizzy or unsteady
• Sunken eyes (your eyes look “sunken” into your face)

What should I do if I’m dehydrated?

If you’re dehydrated, the best thing to do is drink fluids such as water or sports drinks. Avoid caffeinated beverages and drinks with a lot of sugar in them, such as coffee, soda, and juice; these won’t help. You’ll know when your body is rehydrated when your urine looks clear, or light yellow in color.

If you develop more serious symptoms such as extreme thirst, confusion, light-headedness, dizziness, or rapid heartbeat, call your health care provider right away or go to the nearest emergency department. These may be signs of severe dehydration, which usually needs to be treated in a hospital.

Can I prevent dehydration?

Yes. Here are a few things you can do to help prevent dehydration:

• Drink enough water every day (about 8-10 cups), even when you’re not sick.
• If you are sick, make sure that you drink water even if you’re not feeling well. It’s extremely important to keep your body hydrated.
• Make sure to drink extra fluids when the weather is hot and humid, because you’ll be losing water from your body as you sweat.

If you’re going to exercise or play sports, stick to the following hydration schedule:

When to Drink	How Much to Drink
2 to 3 hours before exercising	Drink 16 ounces of fluid
10 to 20 minutes before exercising	Drink 8-10 ounces of fluid
While exercising	Drink 4-6 ounces of fluid every 15-20 minutes
After exercising	Drink at least 16-24 ounces of fluid (this amount may vary individually depending on the intensity of exercise and heat/humidity)

I need to lose weight for a sports event and I’ve heard that “diuretic” medicines work. Can I use them?

If you’re an athlete (such as a wrestler), and you need to make a certain weight to compete in an event, taking diuretics or laxatives (medicines that cause increased urination and watery bowel movements) is not a good idea. Using these medicines can make you feel weak, and may cause serious problems such as changes in your heart rhythm. Anyone who exercises or plays sports should follow the hydration schedule listed above.

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Our health guides are developed through a systematic, rigorous process to ensure accuracy, reliability, and trustworthiness. Written and reviewed by experienced healthcare clinicians from Boston Children's Hospital, a Harvard Medical School teaching hospital and consistently ranked as a top hospital by Newsweek and U.S. News & World Report, these guides combine clinical expertise, specialized knowledge, and evidence-based medicine. We also incorporate research and best practices from authoritative sources such as the CDC, NIH, PubMed, top medical journals, and UpToDate.com. Clinical specialists and subject matter experts review and edit each guide, reinforcing our commitment to high-quality, factual, scientifically accurate health information for young people.