Hydration Is Essential, but Can You Drink Too Much Water?

MDs explain the risks of overhydration, plus how much water you should really be drinking.

Pick up almost any lifestyle magazine, turn to a random page (that isn't an ad), and chances are you'll see some version of the same tip: Drink more water. Dry skin? You're probably dehydrated. (Nope, that's a myth.) Feeling off? Drinking plenty of water is a form of self-care. Not sleeping well? Be sure to increase your water intake during the day, but take it easy in the evenings because you don't want to be running to the bathroom all night.

Given all this pro-hydration advice, it's no wonder some people feel pressured to force themselves to drink eight glasses of water each day—even if, in truth, it's not really in their best interest. Don't get us wrong: water is absolutely an essential part of our overall health, and becoming dehydrated can lead to all sorts of problems. But where hydration is concerned, it is possible to drink too much water. Here's what to know about drinking far more water than you need to, or overhydration, including the signs, risks, and treatments.

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Is it possible to drink too much water?

In short, yes: There is such a thing as drinking too much water—but why is that bad? "Kidneys can excrete up to 28 liters of fluid in a day, but only one liter an hour," says Christina Lang, MD, internal medicine and pediatric physician at UCHealth in Fort Collins. "Drinking more than this can lead to water intoxication and electrolyte imbalances."

According to Natasha Trentacosta, MD, a sports medicine specialist and orthopedic surgeon at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles, overhydration is often seen in athletes if they drink an excessive amount of water. Doing so can dilute the sodium in their bodies, resulting in a condition called hyponatremia.

Additionally, people with certain kidney diseases can become overhydrated without drinking large amounts of water, because they are unable to regulate the excretion of the water in their urine, Dr. Trentacosta explains. "Normally, drinking large amounts of water—even up to 6 gallons—can be managed by the natural ability of our bodies to regulate water excretion through the combined efforts of the pituitary gland, kidneys, liver, and heart," she says. "If any of these organs are dysfunctional, that upper limit can be lowered."

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How much water should you actually drink per day?

If you're wondering how much water you should drink each day, you're not alone, as the varying advice can get confusing. According to Dr. Trentacosta, staying properly hydrated means taking in roughly 30 to 50 ounces of water, and doing so periodically throughout the day. "Hydration includes water from drinks, but also from water-rich or 'wet' snacks like fruit and vegetables," she explains, noting that adequately hydrated people have pale and clear urine.

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Warning signs you're drinking too much water:

The most common signs of overhydration are confusion, disorientation, nausea, and vomiting, Dr. Lang says. She adds that in more severe cases, additional symptoms can include muscle cramping, weakness, increased blood pressure, double vision, and difficulty breathing.

But what exactly is happening to the body when it gets too much water? "The signs and symptoms of overhydration are the result of our electrolytes being diluted," Dr. Trentacosta explains. "Hyponatremia may present with lethargy or altered mental status as the brain is sensitive to sodium levels in the blood."

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What are the biggest risks of drinking too much water?

It is rare, but the truth is that, yes, you can technically die from drinking too much water. As Dr. Trentacosta mentioned earlier, drinking too much water can cause the sodium level in your blood to drop, resulting in hyponatremia. "This can lead to dangerous fluid shifts into the cells of the body, particularly the brain," Dr. Lang explains. "With excessive water drinking, above what the kidney can excrete and/or without replacement of electrolytes (sodium, potassium), a person can have swelling of the brain (cerebral edema), which can be fatal."

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How to prevent and treat overhydration.

Instead of having to deal with the effects of drinking too much water, Dr. Lang says that it's best to avoid doing this in the first place. But if it's too late for that, and you've noticed any of the signs of symptoms we described above, it's best to seek immediate medical care, given the impact hyponatremia can have on your brain.

If you're dealing with severe hyponatremia, a member of your healthcare team may put you on a sodium solution IV to gradually replace the sodium in your blood, according to the National Kidney Foundation. But because it's also important to make sure your sodium levels don't increase too much or too quickly, you'll likely have to stay in the hospital so your condition can be monitored. Your healthcare provider may also give you medication to help manage symptoms like headaches, nausea, and seizures.

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Sources
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  1. National Kidney Foundation, Hyponatremia. Accessed October 22, 2022.

  2. Peechakara BV, Gupta M. Water Toxicity. Accessed October 22, 2022.

  3. Peri A. Morbidity and mortality of HyponatremiaFront Horm Res. 2019;52:36-48. doi:10.1159/000493235

  4. Diringer M. Neurologic manifestations of major electrolyte abnormalitiesHandb Clin Neurol. 2017;141:705-713. doi:10.1016/B978-0-444-63599-0.00038-7

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