Take that, muscle cramps!

Here are the best ways to stop painful cramps — and prevent them from returning.

 Image: © ChesiireCat/Getty Images

A muscle cramp always feels like a surprise. The involuntary contraction strikes without warning, whether it's a charley horse in the middle of night or a back spasm as you reach for an everyday object. But don't let that cramp throw you for a loop. "When it suddenly strikes, don't exercise or tighten the muscle. Just gently stretch it to your tolerance. That helps to relax the muscle and relieve the uncontrolled contraction," says Madhuri Kale, a physical therapist at Harvard-affiliated Brigham and Women's Hospital.

What causes cramps?

Exercising without properly warming up the muscles can lead to cramps. Cramps also occur when a muscle is not able to relax properly (such as from a deficiency of magnesium or potassium in your diet) or when it becomes irritated by a buildup of lactic acid (which can happen if you don't rest your muscle after it has exercised a lot). Dehydration can worsen both of these problems. Kale says older adults often don't drink enough water at night because they want to avoid having to go the bathroom, and they end up dehydrated.

Reduced blood flow to the muscles also can cause cramps. This can occur from narrowing of the arteries to your legs caused by atherosclerosis. It can even happen for stranger reasons. "Some people say they get cramps at night if their feet stick out from under the blankets. Being cold can constrict the blood vessels," Kale says.

Misfiring nerves that get confused because of neurological conditions (such as Parkinson's disease, neuropathy, or spine problems that compress nerves in the low back) can cause cramps as well. Even common foot problems (such as flat arches) can do it.

Finally, Kale says, cramps sometimes result from certain medications, like diuretics, that can cause both dehydration and mineral imbalances. Statin drugs, on the other hand, can cause constant muscle aches, but they rarely trigger cramps.

Relief for cramps

Learn some stretches that provide rapid relief when cramps come.

Kale's shortcut for nighttime leg cramps in the calf: "Sit up in bed, loop the blanket around your foot, and gently pull your toes toward you while you keep the knee straight," she suggests

Alternatively, for cramps in the front of the lower leg, just stand up at the side of the bed, put your weight on your toes, and lift your heels; this gently stretches the cramped muscle.

For back cramps, Kale recommends the "child's pose" yoga posture (see "Move of the month").

For hamstring cramps (in the back of the thigh), sit on the floor with your legs extended in front of you. Slide your hands down your legs until you feel a burning sensation in the cramped muscle. Hold for 30 seconds, then slowly return to a sitting position.

After you've stretched the muscle, Kale recommends putting a heating pad on the area to promote blood flow. Then gently massage the muscle.

Tips to prevent cramps

Kale suggests staying hydrated throughout the day, eating foods rich in magnesium (especially leafy greens) and potassium (bananas, black beans), wearing warm socks at night if you have leg cramps, and keeping your muscles strong and flexible with regular exercises.

Quinine tablets used to be recommended, but aren't anymore unless cramps are disabling. "They can have some bad side effects and interactions with other medications," Kale says.

And one more point: "Cramps are extremely painful, but they're not a sign of serious illness," says Kale. "Stretch the muscle and resume your activity once the cramp goes away."