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 the types and causes of muscle cramps?
Skeletal muscle cramps can be categorized into four major types. These include “true” cramps, tetany, contractures, and dystonic cramps. Cramps are categorized according to their different causes and the muscle groups they affect.
Types of muscle cramps: True cramps
True cramps involve part or all of a single muscle or a group of muscles that generally act together, such as the muscles that flex several adjacent fingers. Most authorities agree that true cramps are caused by hyperexcitability of the nerves that stimulate the muscles. They are overwhelmingly the most common type of skeletal muscle cramps. True cramps can occur in a variety of circumstances as follows.
Injury: Persistent muscle spasm may occur as a protective mechanism following an injury, such as a broken bone. In this instance, the spasm tends to minimize movement and stabilize the area of injury. Injury of the muscle alone may cause the muscle to spasm.
Vigorous activity: True cramps are commonly associated with the vigorous use of muscles and muscle fatigue (in sports or with unaccustomed activities). Such cramps may come during the activity or later, sometimes many hours later. Likewise, muscle fatigue from sitting or lying for an extended period in an awkward position or any repetitive use can cause cramps. Older adults are at risk for cramps when performing vigorous or strenuous physical activities
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 of dehydration 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.
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.