“Drink eight glasses of water a day.” “If you’re thirsty, you’re already dehydrated.” “Hydration is the key to healthy skin.” If you’ve never heard these water mantras before, move over so I can share the rock you’ve been hiding under.
The Guardian published an interesting article this week titled, “The truth about hydration: should you drink eight glasses of water a day?” In it, writer Amy Fleming unpacks the various claims that water, and lots of it, can transform us into energetic, unstoppable, ageless goddesses, and that those drinking less than two liters per day are withered, headache-suffering husks who deserve every misfortune that dehydration rains upon them. What’s real, and what’s junk science?
Here’s what’s true: you should be sure to drink some amount of water every day. Harvard Medical School says four to six cups. Hydration is better for your skin than dehydration. And dehydration has the potential to cause mild headaches. So, drinking water throughout the day has its benefits, and hey, it’s just downright refreshing—and much of the time, it’s free.
But here’s where the science behind “eight glasses a day” and “thirst means you’re dehydrated” gets murkier. For one thing, go ahead and wait until you’re thirsty to down a glass of water, if you prefer, because healthy adults are still well within the body’s ideal water level by the time thirst kicks in. Despite the claims from hydration hawks, there’s no reason that your fluids can’t come in the form of coffee, milk, or even beer, all of which have been shown to hydrate about as effectively as water. And while experts recommend a certain amount of fluid intake each day, there are recommended limits, too. Water intoxication is a real condition than can occur when you drink more water than your body can even pee out, leading to electrolyte imbalance and disrupted brain function. It’s rare, but it can kill. So don’t do that.