Heat cramps are painful, involuntary muscle spasms that usually occur during heavy exercise in hot environments. Inadequate fluid intake often contributes to heat cramps. The spasms may be more intense and more prolonged than typical nighttime leg cramps. Muscles most often affected include those in your calves, arms, abdomen and back, although heat cramps may involve any muscle group involved in the exercise.

If you suspect heat cramps:

• Rest briefly and cool down.
• Drink clear juice or an electrolyte-containing sports drink.
• Practice gentle, range-of-motion stretching and gentle massage of the affected muscle group.
• If your cramps don't go away in 1 hour, call your doctor.