Can I Drink Too Much Water?

Photo-Illustration: The Cut; Photo: fizkes/Shutterstock

At some point, we’ve all made a resolution to drink more water. Maybe we’ve even invested in a gallon-size water bottle, spiked it with lemon, and set reminders on our phones to do hourly chugs. But to what end? Are we really as dehydrated as we’ve been led to believe? As it turns out, no — in fact, it’s pretty easy to overhydrate ourselves.

“Overhydration is a very real thing,” confirms Erica Zellner, a health coach who specializes in sports medicine at Parsley Health. Its most extreme form, known as hyponatremia or water intoxication, is very rare and usually happens alongside medical conditions like uncontrolled Type 2 diabetes or congestive heart failure. Sometimes it can also be drug-induced (say, by the extreme thirst that ecstasy can cause). It is life-threatening and requires immediate hospital treatment, but most people never even get close to that point — according to Zellner, you’d have to be drinking at least two to three liters in as little as fifteen minutes. “It’s really, really difficult to get to the point of water intoxication, because our bodies have wonderful buffer systems to prevent it,” she says.

Water intoxication is dangerous because it throws your salt and electrolyte levels out of whack. “Salts, electrolytes and minerals like potassium and magnesium have to be finely regulated by the kidneys and other barrier mechanisms in the body,” says Zellner. “All of these create a balance so that our muscles can contract and our bodies can send signals from cell to cell from neuron to neuron.”

However, milder forms of overhydration do exist, as Zellner learned the hard way when she drank too much water the day before a Tough Mudder competition. “When I started to run, my legs cramped up so badly that I fell over and couldn’t go on after a couple of miles,” she says. All the water she’d consumed the day before had lowered her salt and electrolyte levels, so that when she started to sweat, she lost even more and her muscles couldn’t contract properly.

So, the lesson there is to always drink something with electrolytes in it, right? Not exactly. “For the average person, normal water should be enough, even on a very hot day,” says Zellner. “The point when you need a sports drink or a coconut water is when your activity lasts longer than an hour, or if you’re sweating so much that you’re actually getting a salty crust on your skin.” Of course, there wouldn’t be anything harmful about drinking a sports drink before that point; you just probably wouldn’t need it. (Zellner also confirms that electrolyte drinks can be helpful in a morning-after situation, if you’re feeling a little delicate after drinking alcohol and dehydrating yourself.)

But in normal situations, you probably don’t need to force yourself to drink if you’re not thirsty. “I think people sometimes challenge themselves to drink quite an unnecessary amount of water,” says Zellner. “Aside from very frequent bathroom breaks, headaches and poor concentration can be signs that you’re overhydrated.” Of course, headaches and poor concentration can also be signs of dehydration, but if you’re three-quarters of the way through a gallon jug of water at your desk, that’s probably not the issue. “For most people, half of your body weight in ounces is a sufficient amount of water a day,” added Zellner. (So, for example, if you weigh 150 pounds, 75 ounces of water ought to do it — a little over nine cups.)

As for the rumors that warm water is better for your gut: If you like drinking it, go for it, but there’s not any particular health benefits associated with water temperature, says gastroenterologist Dr Marvin Singh. “Some people find that having a warm drink first thing in the morning, even just water rather than tea or coffee, does have a positive impact on their digestion, but there’s no concrete literature to support it being more beneficial,” he says.

So, for the most part, you should drink what you like, when you feel like it. Cheers.

Can I Drink Too Much Water?