Muscle cramps facts

Muscle cramps facts

• A muscle cramp is an involuntarily and forcibly contracted muscle that does not relax.
• Almost everyone experiences a muscle cramp at some time in their life.
• There are a variety of types and causes of muscle cramps.
• Numerous medicines can cause muscle cramps.
• Most muscle cramps can be stopped if the muscle can be stretched.
• Muscle cramps can often be prevented by measures such as adequate nutrition and hydration, attention to safety when exercising, and attention to ergonomic factors.

What are muscle cramps?

A muscle cramp is an involuntarily and forcibly contracted muscle that does not relax. When we use the muscles that can be controlled voluntarily, such as those of our arms and legs, they alternately contract and relax as we move our limbs. Muscles that support our head, neck, and trunk contract similarly in a synchronized fashion to maintain our posture. A muscle (or even a few fibers of a muscle) that involuntarily (without consciously willing it) contracts is in a "spasm." If the spasm is forceful and sustained, it becomes a cramp. Muscle cramps often cause a visible or palpable hardening of the involved muscle.

Rest cramps: Cramps at rest are very common, especially in older adults, but may be experienced at any age, including childhood. Rest cramps often occur during the night. While not life threatening, night cramps (commonly known as nocturnal cramps) can be painful, disruptive of sleep, and they can recur frequently (that is, many times a night, and/or many nights each week). The actual cause of night cramps is unknown. Sometimes, such cramps are initiated by making a movement that shortens the muscle. An example is pointing the toe down while lying in bed, which shortens the calf muscle, a common site of muscle cramps.

Dehydration: Sports and other vigorous activities can cause excessive fluid loss from perspiration. This kind ofdehydration increases the likelihood of true cramps. These cramps are more likely to occur in warm weather and can be an early sign of heat stroke. Chronic volume depletion of body fluids from diuretics (medicine that promote urination) and poor fluid intake may act similarly to predispose to cramps, especially in older people. Sodium depletion has also been associated with cramps. Loss of sodium, the most abundant chemical constituent of body fluids outside the cell, is usually a function of dehydration.

Body fluid shifts: True cramps also may be experienced in other conditions that feature an unusual distribution of body fluids. An example is cirrhosis of the liver, which leads to the accumulation of fluid in the abdominal cavity (ascites). Similarly, cramps are a relatively frequent complication of the rapid body fluid changes that occur during dialysis for kidney failure.

Low blood calcium, magnesium: Low blood levels of either calcium or magnesium directly increase the excitability of both the nerve endings and the muscles they stimulate. This may be a predisposing factor for the spontaneous true cramps experienced by many older adults, as well as for those that are commonly noted duringpregnancy. Low levels of calcium and magnesium are common in pregnant women unless these minerals are supplemented in the diet. Cramps are seen in any circumstance that decreases the availability of calcium or magnesium in body fluids, such as taking diuretics, hyperventilation(overbreathing), excessive vomiting, inadequate calcium and/or magnesium in the diet, inadequate calcium absorption due to vitamin D deficiency, poor function of the parathyroid glands (tiny glands in the neck that regulate calcium balance), and other conditions.

Low potassium: Low potassium blood levels occasionally cause muscle cramps, although it is more common for low potassium to be associated with muscle weakness.

What is the treatment of skeletal muscle cramps?

Most cramps can be stopped if the muscle can be stretched. For many cramps of the feet and legs, this stretching can often be accomplished by standing up and walking around. For a calf muscle cramp, the person can stand about 2 to 2.5 feet from a wall (possibly farther for a tall person) and lean into the wall to place the forearms against the wall with the knees and back straight and the heels in contact with the floor. (It is best to learn this maneuver at a time when you don't have the cramp.) Another technique involves flexing the ankle by pulling the toes up toward the head while still lying in bed with the leg as straight as possible. For writer's cramp (contractures in the hand), pressing the hand on a wall with the fingers facing down will stretch the cramping finger flexor muscles.

Gently massaging the muscle will often help it to relax, as will applying warmth from a heating pad or hot soak. If the cramp is associated with fluid loss, as is often the case with vigorous physical activity, fluid and electrolyte (especially sodium and potassium) replacement is essential. Medicines generally are not needed to treat an ordinary cramp that is active since most cramps subside spontaneously before enough medicine would be absorbed to even have an effect.

How can you prevent muscle cramps?

These tips may help prevent muscle cramps:

• Drink plenty of water and other fluids, enough so that your urine is light yellow or clear like water.
• Limit or avoid drinks with alcohol.
• Make sure you are eating healthy foods (especially if you are pregnant) that are rich in calcium, potassium, and magnesium.
• Ride a bike or stationary bike to condition and stretch your muscles.
• Stretch  your muscles every day, especially before and after exercise and at bedtime.
• Don't suddenly increase the amount of exercise you get. Increase your exercise a little each week.
• Take a daily multivitamin supplement.

If you are taking medicines that are known to cause leg cramps, your doctor may prescribe different medicines.

What if muscle cramps keep coming back?

Talk with your doctor if you have muscle cramps that keep coming back or are severe. These may be symptoms of another problem, such as restless legs syndrome.

If cramps keep coming back, bother you a lot, or interfere with your sleep, your doctor may prescribe medicine that relaxes your muscles.

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014