A:

Just about everyone has muscle cramps at one time or another. And they become more common as we age. They may happen after physical exertion (especially if more intense or longer than usual). But no one knows why some people who exercise regularly are more likely to get muscle cramps while others are not.

In fact, the cause of most muscle cramps is unknown. Risk factors include advanced age, pes planus (flat feet), lack of exercise, dehydration and diabetes. But plenty of people with these factors do not have muscle cramps. And most people with muscle cramps have none of these factors.

Many doctors order blood tests to check your potassium, calcium and magnesium levels. But for most people with muscle cramps, these test results are normal.

That said, there are recognized causes of severe or frequent muscle cramps. They include:

• Muscle or nerve injury
• Dehydration
• Low levels of electrolytes such as potassium, magnesium or calcium
• Poor circulation
• Vitamin deficiency (including B1 and B6)
• Medication use (such as diuretics and statins)
• Thyroid disease
• Pregnancy

Your treatment would depend on the cause -- if one can be found. So talk to your doctor. He or she may suggest that you see a neurologist, a specialist in nerve and muscle function.

In the meantime, these tips can help:

• Drink not only water, but liquids that contain salt, potassium and essential electrolytes.
• Stretch out the cramping muscle (which often means standing or walking around).
• Stretch before, during and after exercise.
• Apply heat to the cramping muscle.
• For calf or foot cramps, change shoe wear to improve arch support and cushioning.
• If you are pregnant, ask your doctor, midwife or nurse if you can take magnesium supplements. Studies suggest these may prevent muscle cramps.

Many people with muscle cramps (especially those that happen at night) say that quinine helps. But the best clinical studies question its usefulness. Quinine is no longer available in pill form in the U.S., but you can still find it in tonic water.

Muscle cramps are rarely dangerous. But they can be quite painful, aggravating and unpredictable. So it’s worth trying to find the cause and a safe treatment to stop them.