Nearly Half Of Runners May Be Drinking Too Much During Races

Stay hydrated, don't hydrate. Stay hydrated, don't hydrate. What is a runner to do?

Nearly half of recreational runners may be drinking too much fluid during races, according to a survey of runners by Loyola University Health System researchers.

Expert guidelines recommend runners drink only when thirsty. But the Loyola survey found that 36.5 percent of runners drink according to a preset schedule or to maintain a certain body weight and 8.9 percent drink as much as possible.

Nearly a third of runners (29.6 percent) incorrectly believe they need to ingest extra salt while running. And more than half (57.6 percent) say they drink sports drinks because the drinks have electrolytes that prevent low blood sodium. In fact, the main cause of low sodium in runners is drinking too much water or sports drinks.

"Many athletes hold unscientific views regarding the benefits of different hydration practices," researchers concluded. The study was published in the June, 2011, issue of the British Journal of Sports Medicine.

Drinking too much fluid while running can cause a potentially fatal condition called exercise-associated hyponatremia. It occurs when runners drink even when they are not thirsty. Drinking too much during exercise can dilute the sodium content of blood to abnormally low levels.

Drinking only when thirsty will prevent overconsumption of fluids. "It's the safest known way to hydrate during endurance exercise," said Loyola sports medicine physician Dr. James Winger, first author of the study.

But since the "hydration" response can change with age, good luck with that.