Mayo Clinic Health Library

Heat cramps

Updated: 04-03-2012

Heat cramps are painful, involuntary muscle spasms that usually occur during heavy exercise in hot environments. The spasms may be more intense and more prolonged than are typical nighttime leg cramps. Inadequate fluid intake often contributes to heat cramps.

Muscles most often affected include those of your calves, arms, abdominal wall and back, although heat cramps may involve any muscle group involved in 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
  • Don't resume strenuous activity for several hours or longer after heat cramps go away
  • Call your doctor if your cramps don't go away within one hour or so