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SUNDAY, July 13, 2003 (HealthDayNews) -- Have you ever had a muscle in your arm or leg go into spasm in the middle of an exercise routine or during another kind of strenuous activity?
That means you've experienced heat cramps, which are painful and involuntary spasms caused by low salt levels in your muscles.
So if you perspire heavily, you're probably more prone to the problem because sweating drains your body's salt and moisture. That's why sodium-laden sports drinks are so popular with athletes -- they replenish the body's supplies.
Actually, even if you aren't a big sweater, a lack of fluid can cause your muscles to seize up. In this case, heat cramps may be a symptom of heat exhaustion.
The spasms usually affect muscles in your calves, arms, abdomen and back, although they can occur when you're exerting any muscle group.
If heat cramps creep up on you, the U.S. Centers for Disease Control and Prevention (CDC) offers this advice:
For people with heart problems or on low-sodium diets, the CDC recommends you seek medical attention for heat cramps.
More information
To find out more about heat cramps, visit the U.S. National Center for Environmental Health.