Can You Drink Too Much Water?

We often hear about the importance of drinking plenty of water. But did you know that drinking too much water can be bad for your health?

Drinking excessive amounts of water can overwhelm your kidneys and dilute the sodium content of your blood. The condition is sometimes called water intoxication or hyponatremia. When this happens, water moves into cells – including brain cells – and can cause swelling. Hyponatremia can lead to a host of symptoms, including:

• Headache
• Nausea or vomiting
• Fatigue
• Confusion
• Muscle cramping or weakness

Severe cases can lead to seizures, loss of consciousness or death, though these occurrences are rare. In 2007, hyponatremia caused the death of a radio show contestant after she took part in a water-drinking contest and reportedly drank nearly two gallons over two hours. More recently, actress Brooke Shields said she had a grand mal seizure caused by drinking too much water.

How Much Water is Enough?

The widespread belief that you should drink eight, 8-ounce glasses of water a day for good health is a myth. There is no scientific research behind it.

There’s no standard amount of water you should drink daily – it varies person to person and depends on health conditions and levels of physical activity. The National Academy of Medicine estimates an optimal daily fluid intake is approximately 15 cups for healthy men and 11 cups for women. That includes fluids consumed from foods and beverages. About 20 percent of your daily fluid intake comes from foods.

A good rule of thumb for healthy people is to drink according to thirst. Older adults may have a decreased level of thirst and should make it a point to drink water even if they’re not thirsty. Urine color is another good gauge of hydration: Light yellow is good. Dark yellow indicates dehydration. Also, you may need to drink more than usual if you have vomiting or diarrhea.

How Much Water Is Too Much?

There is no set amount of water that causes water intoxication. The kidneys can process about one liter of fluid per hour, so any amount above that over a number of hours can be risky.

• Among healthy people, endurance athletes tend to be at greatest risk for overhydrating.
• Certain medical conditions such as kidney and liver disorders can contribute to overhydration.
• Certain drugs such as diuretics, anti-psychotics and ecstasy can increase thirst and lead to overhydration.

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University Hospitals has a team of clinical dietitians with the expertise to provide counseling and personalized eating plans for anyone looking to enhance their health, meet nutritional goals or lose weight safely and effectively.