How Much Water Is Too Much?
Your goal is to stay hydrated without going overboard. Learn how much water intake is too much.
We always hear about how good water is for us. But is there such a thing as water overload? Can you drink too much water?
The fast answer? "You absolutely can, and doing so can cause a condition called hyponatremia," says Ginger Hultin, RD, a Seattle-based spokesperson for the Academy of Nutrition and Dietetics. "This is when there's excess fluid in the body that causes low levels of sodium, a critical electrolyte required for proper functioning of the body."
When hyponatremia occurs, the water levels in your body increase and your cells start to swell. Symptoms of hyponatremia range from nausea, vomiting, headache, fatigue and confusion to more serious ones such as seizures, coma and even death, according to the Mayo Clinic.
But how much water is too much? "Drinking more than the kidneys can eliminate could cause hyponatremia in some people," says Hultin, noting that the kidneys can eliminate 27 to 34 ounces of water per hour, or a total of 676 to 947 ounces (20 to 28 liters) per day. More than that might put you in the danger zone.
Exercise and hot weather can lead people to overdo their water intake, Hultin says, citing reports of hyponatremia in soldiers and in marathon runners. "Some of the biggest risk factors [of hyponatremia] include drinking excessive water while sweating or during prolonged sports of over an hour and not replacing electrolytes like sodium with food or properly formulated sports hydration beverages," she adds.
So how much water do you actually need in a day? For the typical healthy adult living in a temperate climate, about 15.5 cups (125 ounces) for men and 11.5 cups (91 ounces) for women should do it. These are the intakes established as adequate by The National Academies of Sciences, Engineering, and Medicine.
When assessing your water needs, be aware that you get water from sources besides water. "Keep in mind that you get fluids from the foods you eat and also beverages like juice, tea and coffee," says Hultin.
Also be aware that your water needs can change based on your activities, lifestyle, life stage (such as pregnancy or older adulthood) and state of health. Curious about how much water intake will meet your unique needs? A registered dietitian nutritionist can help you determine this. You can find one in your area by using the "find an expert" tool at eatright.org.
Amy Gorin, MS, RDN, is a registered dietitian nutritionist and owner of Amy Gorin Nutrition in the New York City area. She's a regular contributor to many publications, including EverydayHealth.com, ReadersDigest.com, NBCNews.com, and more. She also pens a recipe-focused blog, Amy's Eat List, where she shares easy, healthy recipes. Connect with her on Instagram, Facebook, Twitter and Pinterest.