"Drink more water" seems to be the all-encompassing solution to life. People swear it can ease sickness, eradicates exhaustion, clears pimples, helps you lose weight, etc. Hydration sustains life — scientists search far and wide for planets that have H2O. But there is such a thing as drinking too much water, and it can kill you.
First, it's important to know that every substance has a lethal limit. Water's lethal limit is way higher than, say, alcohol or hard drugs — but it does exist. It's 90 milliliters per kilogram, according to a study on rats, Gizmodo reported. In other words, assuming the same effect on humans, it's highly inadvisable for a 150-pound person to drink six liters (approximately 1.6 gallons) of water at once. In fact, based on the study, if 100 people did that, 50 of them would die.
The condition is called hyponatremia — it means water intoxication. Under normal circumstances, if you drink more than enough water to hydrate your body, you'll just pee the rest out. But if you drink a lethal amount of water, osmosis will transfer the extra H2O to your cells, causing them to swell — and if the water reaches your brain cells, your brain drowns.
"You should drink only when you need to, when you are actually thirsty," said Dr. James Winger, a family medicine professor at Loyola University Medical Center, according to the New York Times. "Thirst is a very reliable indicator," he added.
So who's died from hyponatremia? Mostly athletes and people on drugs. The condition became more relevant when marathon runners started dying from it a couple decades ago, according to the Times. They were mostly slower runners who didn't sweat much and therefore overcompensated by drinking too much water in their attempts to stay well hydrated.
Drinking too much water while exercising is the most innocent way to drown your brain — but overhydration while using the synthetic rave drug MDMA, also known as Molly or Ecstasy, has often caused hyponatremia as well.
Amphetamines cause feelings of thirst in the body. This, combined with the paranoia that causes people to feel like they'll die from dehydration while on the drug, ironically creates the perfect storm: people drink themselves to hyponatremia.
Don't get too alarmed — remember, you'd need to drink at least a gallon of water almost at once to drown your brain. But experts have said there's no need to drink eight glasses of water a day to stay adequately hydrated, either.