New Study Says Runners Should Go Easy on Water

In a finding that flies in the face of decades of advice on the importance of hydration, research now suggests that overhydration poses a greater danger to runners, triathletes and even hikers than does dehydration. The New York Times reports that the study, published in the New England Journal of Medicine, involved 488 runners in the 2002 marathon. According to the Times, the runners gave blood samples before and after the race, and while most were fine, 13 percent of them drank so much that they had hyponatremia, or abnormally low blood sodium levels. Three had levels so low that they were in danger of dying. The Times reports that in 2003, U.S.A. Track & Field, suspicious of the risks of hyponatremia, changed its guidelines to warn against the practice of drinking a great deal of water before a race.