Coaching Management, 13.8, September 2005, http://www.momentummedia.com/articles/cm/cm1308/bbhydration.htm
In April, the New England Journal of Medicine published a study involving 488 runners in the 2002 Boston Marathon. It showed that 62 of those runners drank so much water or sports drink during the race that they had extremely low sodium levels, and three had sodium levels so low they were in danger of dying.
Should high school and college track and field coaches rethink their hydration advice for athletes in light of this highly-publicized study? In general, the answer is no, according to Dr. Marvin Adner, Medical Director for the Boston Marathon. Adner says that dangerously low blood sodium levels, also known as hyponatremia, are most common in slower athletes who participate in long-distance or long-duration events, and the condition is usually not an issue in the shorter races associated with track and field.
“Track and field athletes do not typically share the same risks as marathon runners,” says Adner. “If we’re talking about athletes who run distances like the quarter mile, they probably aren’t at risk. Athletes who compete for four hours of constant moderate exercise, such as a marathon, and who drink while they compete, are most at risk.”
The runners in the Boston Marathon study who developed complications from hyponatremia tended to be slower, taking four or more hours to complete the race, which gave them ample time to consume liquids. Those suffering from the condition drank about three liters of water throughout the race and actually gained weight during that time.
Adner advises coaches to monitor their athletes during long training sessions and to have them drink to maintain fluid levels. “If athletes are doing long workouts sweating and drinking a lot for a period of four hours or more, monitor their weight fluctuations,” he says. “If they’re gaining weight during a training situation, that’s a sign of overhydration. And if they’re losing weight, they need to drink more.”