A recent study shows that athletes who drink too much water during strenuous exercise may be at risk for hyponatremia, or overhydration.
W. Larry Kenney, professor of physiology and kinesiology, said hyponatremia happens when athletes drink "a lot of fluid in excess of sweat they're losing," but added that it is an extremely rare condition.
Hyponatremia happens when the excess water in an athlete's body dilutes the sodium levels present, causing symptoms that are similar to dehydration, such as lightheadedness and nausea, Kenney said.
"It can cause the brain to swell if the sodium level gets low enough," which can result in death, he said.
Anna Graziano (freshman-division of undergraduate studies) said her sister once overhydrated, but only experienced fatigue and visited a doctor. "If you drink too much water, it flushes all the minerals out of your system," she said.
However, hydration in athletes is still important. "I don't want to scare athletes out of drinking appropriate fluids," Kenney said.
Kristine Clark, sports nutrition director and assistant professor of nutrition, said that while she doesn't see hyponatremia very often in the athletes she treats, "it is a small problem in a small section of the population" and can lead to health problems that are more dangerous than those caused by dehydration.
"It is usually a problem in endurance athletes, those that are participating in triathlons, marathons and long-distance bicycling," she said.
Clark said that in most cases, athletes do not overhydrate; rather, they are far more likely to become dehydrated as a result of not drinking enough fluids.
"It is also a problem based on what you're hydrating with. ... It happens with sports drinks because athletes are over-consuming calories," she said.
Clark also said that people who exercise aren't replacing electrolytes when they replace lost body fluids by drinking water only.
"Athletes lose body water with sweat ... but dilute blood plasma with too much water," she said.
The study on hyponatremia was published earlier this month in the New England Journal of Medicine.
