Water: How much to drink?

The question of how much daily water you should drink has come up again. This time a recent study in the Proceedings of the National Academy of Sciences says that your brain will tell you exactly how much to drink.

No need to sweat the nine glasses a day for women and the 13 for men that the Mayo Clinic recommends. Or the eight-glass rule, which seems to have become common wisdom. Researchers say there isn’t enough proof to back up those numbers. In fact, according to the study, your body will tell you when to drink and when not to. Bottom line: Drink when you’re thirsty. Drinking when not thirsty might actually confuse the brain, the researchers said.

forget about those eight glasses of water, according to a new study.


Researchers studied 19 people, who were asked to exercise. By the time the subjects had finished they’d lost nearly 1 percent of their body weight in water. Obviously they were thirsty. So researchers watched their brains under an MRI scanner while they drank water. They were told to continue drinking even after they were no longer thirsty. The less enjoyable it became for the subjects to drink, the harder it became for them to swallow. Eventually areas of the brain that control swallowing became overactive, limiting the benefit of the water.

The moral of the story: Just listen to your brain.


Stacy Finz