( Many people are drinking too much wate...)Runners -- Let thirst be your guide

Many people are drinking too much water, including sports drinks, when exercising, a practice that could put some individuals engaging in prolonged types of endurance exercise at risk of potentially lethal water intoxication, say international experts who study disorders of water metabolism. Such exercise includes marathons, triathlons, and long distance cycling.

This serious condition, known as exercise-induced hyponatremia (EAH), could be prevented if only people would respect their personal thirst “meter,” or would undertake a “sweat test” to determine how much water they actually need to drink in order to replace just the body fluids lost during exercising, the researchers say.

A group of experts in this condition has issued a number of papers and recommendations, including an international consensus statement on this disorder published in the Clinical Journal of Sports Medicine in 2005. Joseph Verbalis, M.D., Professor and Interim Chair of the Department of Medicine at Georgetown University Medical Center and a member of this group, recently updated the scientific community on the causes of this disorder in the May issue of Sports Medicine.

Verbalis says the goal of the group is to understand the biological basis of EAH, and in that way, assure that no athlete ever succumbs to it again. A number of marathon runners have died from EAH, including one at this year’s London Marathon in April. One recent study found that 13 percent of Boston marathon runners suffered from EAH, though most cases are mild enough so that they are not noticed by the athletes themselves.

“The tragic aspect of the deaths that have occurred from EAH is that these are healthy young people who otherwise would have lived normal, long lives,” says Verbalis, who is also Chief of the Division of Endocrinology and Metabolism at Georgetown.

“The data clearly indicate that EAH is caused by excess drinking during endurance exercise activiti
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Source:Georgetown University Medical Center