Night leg cramps: What causes them?

A muscle cramp is an involuntary, sustained tightening (contraction) of one or more of your muscles. It can result in intense pain and an inability to use the affected muscles. Night leg cramps are contractions of the leg muscles, usually in the back of the lower leg (calf). They often occur just as you're falling asleep or just as you're waking up.

The exact cause of night leg cramps isn't known. Some experts believe they may be due to abnormal processing of electrolytes — essential elements and chemical substances your body needs for basic functions — by muscles. Almost everyone has occasional leg cramps. But they occur most often in older adults. Common causes of night leg cramps include:

• Muscle overexertion
• Prolonged sitting
• Dehydration
• Pregnancy
• Diabetes
• Decreased potassium levels
• Neuromuscular disorders, such as Parkinson's disease
• Certain medications, such as albuterol, niacin, diuretics, and some calcium channel blockers and antipsychotic medications
• Alcohol use

If you do get a leg cramp, you may be able to make it go away by:

• Walking on the affected leg
• Massaging the affected muscle
• Straightening your leg and flexing your foot toward your knee until you feel the calf muscles stretch
• Applying a cold pack to the affected muscle
• Taking a hot bath

To help prevent night leg cramps:

• Drink plenty of fluids during the day.
• Stretch your leg muscles before bedtime.
• Get adequate potassium in your diet.

If you have frequent and severe leg cramps at night, talk to your doctor. Treatment results vary. But the most effective treatments based on current research are:

• Vitamin B-12
• Gabapentin

Night leg cramps should be distinguished from another common cause of night leg discomfort called restless legs syndrome, a condition in which your legs have a creepy, crawly or fidgety sensation unless you move them. The sensation often worsens as night approaches. Restless legs syndrome is a neurologic condition that requires different treatment from that of night leg cramps.