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UVA Expert Challenges U.S. Obsession with Hydration


During hot summer weather some people worry about dehydration – especially when exercising, but an expert at the University of Virginia says we may actually be drinking too much fluid.  

Dr. Mitchell Rosner, chair of the Department of Medicine at UVA, never carried a water bottle as a kid, and he’s not convinced the average person today needs to worry about fluid intake.

“There’s sort of a mythology that’s come up around the idea that you have to drink,  you have to maintain your hydration, and you need all this water," he says.  "There’s really not a lot of evidence that that is the case.”

True, he adds, there are circumstances where drinking water – even before exercise – would be wise.

“A good example is summer football practice where kids are going to be sweating profusely.  In those circumstances it’s important to drink ahead.”

But drinking too much water too fast can overwhelm our kidneys and upset the balance of sodium in our blood causing headaches, nausea, seizures or even death.

"That happens rarely," Rosner says, "but it can happen in circumstances where people are really trying to push themselves to drink a whole lot of fluid when they don’t really need that."

He notes most people can tolerate a small degree of dehydration.

“If you watch elite runners during their marathons, they rarely take in fluid during those times.”

And what about sports drinks.  Are they a good choice for sweaty athletes?

"My concern with many of the sports drinks is that more than anything they’re a source of sugar and extra calories that are not of great nutritional value, and the electrolyte composition of those sports drinks tends to be pretty low."

Rosner says water is the best bet, and there’s an easy way to tell if you need some.

"I have found repeatedly that if people use thirst as their guide, they do just fine."

And, of course, drinks that contain alcohol or caffeine are not helpful when hydration is the goal.