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:
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.
eMedicineHealth Medical Reference from Healthwise
To learn more visit Healthwise.org