Within the last few years the condition known as hyponatremia has begun to attract the attention of sports
medicine physicians, exercise physiologists, and the medical directors at some
of the larger marathons around the country.
Hyponatremia has been called water
intoxication because of the symptoms it produces. According to Dr. Tim Noakes,
Professor of Exercise & Sports Science Director at the University of Cape
Town, a person with hyponatremia looks like he or she
is mildly drunk. They can’t concentrate
normally…they forget what you were talking about and start to concentrate
elsewhere.”
Hyponatremia
occurs when the body becomes dangerously low in sodium. It’s caused when you literally take in too
much water. Although scientists have
known about it for a long time, it has only been in the last few years as more
runners have been competing in marathons that it has become a concern. According to Dr. Noakes,
fluid has to be ingested at high levels for several hours for hyponatremia to occur.
He suggests that a runner would have to be drinking water regularly for
at least four to six hours to develop the condition. So runners taking four to six hours or more
to run a marathon are at particular risk.
Unfortunately, symptoms of hyponatremia
tend to mimic those of severe dehydration and/or heat exhaustion. By giving the athlete more water to drink the
hyponatremia becomes worse, as more sodium is flushed
out of the system. If a runner with hyponatremia is given fluids intravenously, they can suffer
a fatal reaction. Dr. Noakes and other sports medicine professionals recommend
that physicians and other medical personnel at road races be alert for signs of
hyponatremia.
One of the earliest symptoms is a craving for salty food. Although hyponatremia
is rare, it’s wise to be aware that it can occur, particularly if you’re
running a marathon in unusually hot weather.
Hyponatremia serves as a reminder that water is good, but don’t forget sports drinks, which replenish your body with the sodium, potassium, and other trace minerals you lose through sweat. It’s worth repeating: if you’re going to be running (or racing) for longer than an hour, you should be drinking a sports drink as well as water.