Drinking water even when not thirsty? Don’t, researchers say

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Hyponatremia – a condition that is a direct result of too much water or sports drinks intake – has become one of the major reason for deaths of marathon runners and experts have suggested that the simplest way to reduce risk of hyponatremia is to drink water only when you are thirsty.

According to James Winger, MD, Loyola University Medical Center sports medicine physician consumption of fluid only when you are thirsty is an innate thirst mechanism guide that will help you limit drinking in excess and reduce the risk of developing hyponatremia while providing sufficient fluid to prevent excessive dehydration.

For those of you who are not aware, exercise-associated hyponatremia (EAH) occurs when drinking too much overwhelms the ability of the kidneys to excrete the excess water load. Sodium in the body becomes diluted. This leads to swelling in cells, which can be life-threatening.

Some of the symptoms of mild EAH include lightheadedness, dizziness, nausea, puffiness and gaining weight during an athletic event. Symptoms of severe EAH include vomiting, headache, altered mental status (confusion, agitation, delirium, etc.), seizure and coma.

According to the guidelines published in the Clinical Journal of Sport Medicine, there have been instances wherein EAH has occurred during endurance competitions such as marathons, triathlons, canoe races and swimming; military exercises; hiking; football; calisthenics during fraternity hazing; and even yoga and lawn bowling.

Athletes are often recommended to consume as much fluid as they can or drink more than their thirst dictates by, for example, drinking until their urine is clear or drinking to a prescribed schedule. But excessive fluid intake does not prevent fatigue, muscle cramps or heat stroke.

“Muscle cramps and heatstroke are not related to dehydration,” Dr. Winger said. “You get heat stroke because you’re producing too much heat.”

Modest to moderate levels of dehydration are tolerable and pose little risk to otherwise healthy athletes. An athlete can safely lose up to 3 percent of his or her body weight during a competition due to dehydration without loss of performance, Dr. Winger said.

The guidelines say EAH can be treated by administering a concentrated saline solution that is 3 percent sodium – about three times higher than the concentration in normal saline solution.

The guidelines are published in an article titled “Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015.” in the Clinical Journal of Sport Medicine.