Why Water Is Not the Best Drink to Fight Dehydration

July 12th 2016

Tricia Tongco

Whether you're trying to catch Pokemon outdoors or sweating it out in a non-air-conditioned home, you'll probably find yourself working up a thirst during these hot, summer days.

Your first instinct might be to reach for a cold glass of water. But hold up: The New York Times reported that other beverages may be better at rehydrating you.

The Times based its conclusion on a "beverage hydration index" developed by a 2015 British study that tracked how long 13 common beverages remain in the body after being consumed. Fluids that last longer in the body provide more hydration, the Times reported.

The following beverages have a "significantly higher hydration index" than water, according to the Times. In other words, these drinks are more efficient at hydrating you than water:

  1. Oral rehydration solution (e.g. Pedialyte)

  2. Fat-free milk

  3. Whole milk

  4. Orange juice

The top fluid isn't too surprising: Drinks such as Pedialyte are specifically designed to help prevent dehydration resulting from vomiting and diarrhea.

But milk?

It might be hard to imagine quenching your thirst with a tall glass of dairy on a hot day. But the truth is milk has a unique advantage over water. Ronald J. Maughan, a hydration expert from Loughborough University and the lead author of the study, explained:

"Normally when you drink, it signals the kidneys to get rid of the extra water by producing more urine,” Maughan said. “However, when beverages contain nutrients and electrolytes like sodium and potassium, as milk does, the stomach empties more slowly, with a less dramatic effect on the kidneys.”

Another surprising finding: With the same hydration index as water, "coffee and beer are not dehydrating, despite common beliefs to the contrary," the Times reported.

Thanks to this study, we now know hydrating doesn't have to be such a boring, water-only affair.

[h/t The New York Times]