The Blog

Water, Water Everywhere . . .

And if you're thirsty you should drink. Or, why the Cult of the Nalgene bottle is misguided.

12:00 AM, Jul 1, 2005 • By STANLEY GOLDFARB
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So is there any benefit to water-bottle toting and forced intake? To those who suffer from kidney stones and those with recurrent bladder infections, some incremental fluid intake is beneficial. But the idea that everyone who exercises needs to force fluids in order to be adequately hydrated and avoid calamity is simply not true. In fact, as was recently reported in the New York Times--just before the running of the New York Marathon--the excess consumption of water during situations such as a 26 mile run is dangerous. Recommendations to consume water at a rate faster than about a pint every half hour are excessive, as recently reported in the European Journal of Applied Physiology. The reason for this is that the body actually generates water through the metabolism of fats and starches and sugars during intense exercise so that large volumes of excess water are not needed and, if consumed too quickly, can overcome the kidneys' robust excretion capacity and lead to a dangerous dilution of body fluids, brain swelling, loss of consciousness, and even serious brain injury.

And by the way, there is no evidence that the few ounces of extra water in the system improve the luster of your skin, either. Given the fact that those few ounces distribute themselves uniformly in the 35 quarts throughout the body--including the liver, muscles, brain, and skin--you cannot notice them. The idea that drinking water can "flush out impurities from your system" is an idea that also belongs in the toilet. The kidneys handle water in a manner that separates the amount of water excreted from the elimination of the waste products of metabolism as well as salt, potassium, calcium and the many other components of the urine. Drinking all that water dilutes the urine but does little else.

So water-bottle-toters of the world unite and liberate yourselves from the belief that drinking all that water keeps you healthy or attractive. Unless you are engaged in really intense work in a hot environment, drink when you're thirsty--it's nature's way. If you are running a marathon, drink in moderation as the guidelines suggest. And if you do get a little dry and thirsty during your 20 minutes of spinning at the gym, a trip to the oh, so inexpensive water fountain will get you and your body fluids back to where they need to be.

Stanley Goldfarb MD is associate dean of clinical education at the University of Pennsylvania School of Medicine and a nephrologist.