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Quick Facts

Overhydration

By

The Manual's Editorial Staff

Last full review/revision Jun 2020| Content last modified Jun 2020
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Everyone needs water and electrolytes (minerals, such as sodium and potassium, that help with many body functions) to be healthy. Normally, your body automatically balances your level of water and electrolytes. Drinking gives you what you need, and being thirsty tells you when you need to drink. Your kidneys automatically pee out extra water as urine.

What is overhydration?

Overhydration is having too much water in your body. This happens when your body takes in more water than it puts out.

  • In a healthy person, drinking extra water is unlikely to cause overhydration because whatever isn't needed goes out in the urine

  • Usually, overhydration happens when your kidneys aren’t able to pee out extra water

  • Extra fluid may give you swollen legs or have trouble breathing

  • Overhydration affects the balance of electrolytes in your body, which can cause symptoms such as confusion or seizures

What causes overhydration?

Normally, your body automatically balances the amount of water and electrolytes it has. If you have too much water, your brain signals your kidneys to make more urine.

The two main causes of overhydration include:

  • A medical problem that keeps your kidneys from getting rid of extra water

  • Drinking way more water than your kidneys can handle

Medical problems that could keep your kidneys from getting rid of extra water include:

People don't usually drink way too much water, but this can happen when:

  • Athletes drink more than they need because they don't want to get dehydrated

  • People have a mental problem that causes them to drink too much water

What are the symptoms of overhydration?

You often have no symptoms.

If you have heart, kidney, or liver problems you may have symptoms like:

  • Fluid swelling in your lower legs

  • Fluid in your lungs causing trouble breathing

If you drink way too much, you may:

  • Feel tired, weak, and confused

  • Urinate a lot

How can doctors tell if I have overhydration?

Doctors can usually tell from your symptoms and a physical exam. Sometimes, they'll do blood and urine tests.

How do doctors treat overhydration?

When possible, doctors treat the cause of your overhydration. Doctors may have you:

  • Limit the amount of fluid you drink, often less than 4 cups a day for several days

  • Sometimes, take medicines that make you urinate more (diuretics, sometimes called water pills)

  • Be cared for in the hospital to adjust your fluids and electrolytes if they are severely out of balance

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