Heat cramps usually affect people who sweat a lot during strenuous activity. This sweating depletes the body’s salt and moisture.  The low salt level in the muscles causes painful cramps.  Heat cramps may also be a symptom of heat exhaustion.  Heat cramps are muscle pains or spasms—usually in the abdomen, arms, or legs—that may occur in association with strenuous activity. If you have heart problems, or are on a low-sodium diet, get medical attention for heat cramps.

If medical attention is not necessary, take these steps:

• Stop all activity, and sit quietly in a cool place.
• Drink clear juice or a sports beverage.
• Do not return to strenuous activity for a few hours after the cramps subside, because further exertion may lead to heat exhaustion or heat stroke.
• Seek medical attention for heat cramps if they do not subside in one hour.