What Are Nocturnal Leg Cramps?
Benign nocturnal leg cramps, sometimes known as a charley horse, are muscle spasms in the calf that can occur one or many times during the night. Cramping may also occur in the soles of the feet. They typically last from a few seconds to a few minutes. Some people experience them regularly, others only on isolated occurrences.
Causes of Nocturnal Leg Cramps
In many cases, the cause of nocturnal leg cramps remains unknown. Among the conditions that might cause leg cramps are:
- Calcium and phosphorus imbalances can cause cramping, particularly during pregnancy. Imbalances in these minerals can also occur when fluid levels in the body become low, for example from taking diuretics, excessive perspiration, vomiting, or diarrhea.
- Low potassium or sodium (salt) levels.
- Deficiencies of a nutrient called hesperidin, an antioxidant flavonoid found in oranges and other citrus fruits, have also been linked to nocturnal leg cramps.
- Overexertion, standing on concrete for long periods, or prolonged sitting (especially with the legs contorted) may contribute to nighttime cramps.
- Having structural disorders in the legs or feet (such as flat feet) may increase the risk for cramps.
- Among the many medical causes of muscle cramping include hypothyroidism, Addison's disease, uremia, hypoglycemia, anemia, and certain medications. Various diseases, such as Parkinson's, that affect nerves and muscles cause leg cramps. Peripheral neuropathy, a complication of diabetes in which the nerves in the extremities are impaired, can cause cramp-like pain, numbness, or tingling in the legs. Patients with kidney disease undergoing dialysis are also prone to leg cramps.
Individuals at Higher Risk for Nocturnal Leg Cramps
Nocturnal leg cramps occur at all ages but peak at different times. They are particularly common in adolescence, during pregnancy, and in older age, affecting up to 70% of adults over age 50 at some point.
Pregnant women and those taking diuretics are also at risk for leg cramps because of low calcium levels and an imbalance in calcium and phosphorus.
Consequences of Nocturnal Leg Cramps
Nocturnal leg cramps, like restless legs syndrome, rarely have any serious consequences. However, they can be extremely painful and long-lasting. In some cases, severe and persistent symptoms can cause chronic insomnia and considerable mental distress.
Managing Nocturnal Leg Cramps
Once a cramp begins, straighten the leg, flex the foot upward toward the knee, or grab the toes and pull them toward the knee.
Walking or shaking the affected leg, then elevating it, may also help.
If soreness persists, a warm bath or shower or an ice pack may bring relief.
Preventing Nocturnal Leg Cramps
Lifestyle Tips. Nighttime leg cramps are generally treated with lifestyle changes.
- Everyone with leg cramps should drink plenty of water (at least 6 - 8 glasses daily) to maintain adequate fluid levels.
- Pregnant women and others who get legs cramps due to low calcium levels should reduce milk intake, because drinking milk does not correct the underlying imbalances in calcium and phosphorus. Instead, they should boost calcium levels by taking nonphosphate calcium supplements.
- To prevent cramps from occurring, nightly stretching exercises may be the best preventive measure. Patients should stand about 30 inches from a wall and, keeping the heels flat on the floor, lean forward and slowly move the hands up the wall to achieve a comfortable stretch. A few minutes on a stationary bicycle at bedtime may also help.
- While in bed, loose covers should be used to prevent the toes and feet from pointing, which causes calf muscles to contract and cramp. Propping the feet up higher than the torso may also help.
- During the week, swimming and water exercises are a good way to keep muscles stretched, and wearing supportive footwear is also important.
Quinine. Quinine had been widely used to prevent leg cramping but was banned by the FDA for over-the-counter pharmacy sales because it was reported to cause some serious, although rare, side effects, including bleeding problems and heart irregularities. Other, less serious side effects include headaches, vision problems, and rash
The FDA has since banned the marketing of most quinine drugs, cautioning against the off-label use of the drug to treat RLS. Only one form of the drug, Qualaquin, is approved for treatment of some types of malaria. Pregnant women and those with liver problems should avoid quinine in any form.
Supplements. Some small studies indicate that the mineral magnesium, taken as magnesium citrate or magnesium lactate, may provide some benefit, including in pregnant women with leg cramps.
In one small study, taking vitamin B complex was helpful. Other supplements tried for leg cramps include vitamin E, calcium, and potassium or sodium chloride, but these do not appear to be very effective. Sodium chloride (salt) may be helpful, but Western diets already contain excessive sodium.
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