Most people lose as much as 1 qt (1 L) to 2 qt (2 L) of fluid during 1
hour of exercise. When you are not drinking enough fluids, your muscles get
tired quickly, and you may have leg cramps while walking or running.
If you are an athlete,
you can lose as much as 3 qt (3 L) of fluid an hour
during an intense workout. Fluid loss in endurance activities such as distance
running, cycling, strenuous hiking, or cross-country skiing can be severe.
These types of activities can quickly lead to heat exhaustion.
In endurance athletes, dehydration can cause symptoms, called post-extreme
endurance syndrome (PEES). Symptoms of PEES include decreased body temperature,
nausea, vomiting, diarrhea, dizziness, headache, muscle cramps, and an
inability to drink fluids.
Distance runners and other endurance
athletes are not the only ones to have problems with dehydration. Football,
basketball, and hockey players all may lose large amounts of fluid during a
game. High school and college wrestlers often decrease their fluid intake and
promote excessive sweating before a match in order to “make weight.”
To protect yourself from dehydration:
Drink plenty of water every
Take water with you when you exercise.
alcoholic drinks, which increase dehydration and make it hard to make good
Do not take salt tablets. Most people get plenty of salt
in their diets. If you are worried about replacing minerals lost through
sweating, use a sports drink.
Stop working outdoors or exercising
if you become dizzy or lightheaded or you feel very tired.
It is important to protect yourself from dehydration in
extremely hot or dry weather and at high elevations. Exercise early in the day
or later in the evening when it is cooler.