Too Much Water Can Kill
Long distance runners and other endurance athletes have long
been educated to believe that drinking lots of fluids during a
long distance or endurance event was critical. And if you didn't
drink enough water, you ran the risk of dehydration.
Researchers - studying 488 runners in the 2002 Bost Marathon
found that the bigger danger is in drinking too much fluid
(water or sports drinks) rather than not enough. They found that
62 of the 488 runners, more than one in eight, had a serious
fluid and salt imbalance after the event. And three of them were
in the danger zone.
Hyponatremia - a condition where drinking too much water or
other fluids to the point where the salt level in the body drops
too much - can develop during marathon races where the runners
drink constantly to stave off dehydration.
Runners who actually gained weight (anywhere from 4-11 pounds)
during the event and very thin runners are most at risk. Runners
who drink sports drinks with very little salt in them are least
at risk. The goal of drinking during a race is to replace water
that is lost, not to take in more than you are losing.
A good way to learn how much is right for you is to weight
yourself before a heavy training session. Then drink and record
how much liquid you consume during the trainging. Then weight
yourself again. If you find that you weight more after the
training than before, you should cut down on your liquid intake.
By performing this exercise, you will learn how much liquid you
really need to injest during an event and be able to pace
yourself accordingly.
Hyponatremia can begin with confusion and lethargy and can
progress rapidly to more severe symptoms. They can include
twitching, siezures, stupor, coma and even death.
In recent years, hyponatremia has killed several amateur
marathon runners as well as competitors in the Marine Corps
Marathon.
To learn more about hyponatremia and proper hydration during
events, visit http://usatf.org/groups/coaches/library/hydration/