Muscle cramps (also called Charlie horses) are painful spasm that mainly affects muscles in the legs and feet. A cramp generally last only a few minutes and then ends on its own, although massage and stretching can hasten the process and certain foods may help to prevent its reoccurrence.
The human body is made up of about 600 groups of muscles, which constitutes 40% of an average person’s weight. Each muscle is made up of many thousands of long fibers bound together with connective tissue. The bundle fibers can shrink or lengthen, allowing muscles to contract or relax.
How muscles get energy
Most of the fuel necessary for muscular activities comes from glucose, the end product of carbohydrate metabolism, which is stored as glycogen in the liver and muscles. Vitamins, particularly those in the B group, are crucial to the process that converts carbohydrates, proteins, and fats to energy. In fact, our need for thiamine is directly related to the amount of energy we expend.
We need iron to form hemoglobin, the blood pigment that supplies muscles with oxygen for energy conversion. Also critically important to muscle function are sodium, potassium, and electrolytes, because their electrically charged particles (ions) relay nerve impulses from the brain to the muscles, instructing them when to contract and relax. Calcium is the trigger for muscle contraction. And to come full circle, potassium is stored in the muscles with glycogen and—like glycogen—it is rapidly depleted when the muscles undergo a vigorous workout.
When muscles burn glycogen for energy, lactic acid forms as a waste product and remains in the muscle tissue until circulating blood clears it away. During periods of intense exercise, a buildup of lactic acid can cause severe muscle pain and fatigue. The pain, which is similar to muscle cramps, dissipates with rest, which allows blood to remove extra lactic acid.
The spasms of true muscle cramps may be caused by an inadequate supply of blood to the muscle, overstretching, or injury. The correct fluid balance is important in muscle function. If the fluid volume is too low, the electrolyte balance is thrown off killer, the kidneys respond by conserving sodium at a high rate, fluid is retained in the tissues, and there is not enough circulating fluid to flush out waste products and keep the muscle contraction mechanism working smoothly. There should be enough water to keep electrolyte in the proper concentration for relaying impulses from the nerves to the muscles, but not too much water, which dilutes the blood and lowers electrolyte concentration.
Electrolyte depletion is not often a problem, because these minerals are amply supplied by a properly balanced diet. Although the electrolytes are excreted in sweat, the amounts loss is very small, even with profuse perspiration during vigorous activity. The exception is potassium, which is drawn out of body stores along with glycogen.
Managing muscle cramps
Individuals who may suffer from Charlie horses include athletes, who can deplete their glycogen reserves through very intense activity and lose potassium and salt in heavy perspiration; those being treated for hypertension with beta-blocking drugs or certain diuretics, which increases the amount of potassium excreted in the urine; and women in the later months of pregnancy, who lose larger quantities of potassium in the urine.
A daily serving of high-potassium food—for example, a handful of dried apricots, pecans, walnuts, or sunflower seeds; a glass of tomato juice or citrus juice; or a banana can help to banish muscle cramps and prevent their recurrence. Caffeine and nicotine constrict blood vessels, decreasing the circulation to the muscles and contributing to muscle cramps. If muscle cramps are a problem and you smoke, make every effort to quit; also switch to decaffeinated beverages if you haven’t already done so.
People confined to bed rest or chair rest for extended periods often suffer muscle Charlie horses. Apart from dietary measures, the best remedy is regular exercise to tone the muscles and improve the circulation. Try curling and uncurling the toes a dozen times in a quick succession; alternatively, straighten the leg, bend the foot upward, and then extend the foot and point he toes a dozen times in quick succession. Repeat these exercises throughout the day.
Occasional cramps that abate within a few minutes are no cause for concern. Frequent or prolonged cramps or spasms accompanied by other symptoms, particularly in older adults, should be evaluated by a doctor.
Some people are awakened during the night by a jerking of their leg muscles; others suffer from an aching, uneasy sensation that doctors call “restless leg syndrome.”Certain medications that affect the nervous system may cause theses conditions; often they occur for no apparent cause. In some cases, drugs may help; getting out of bed and walking. Or frequently changing positions, may give some relief.