Muscle spasms, which can affect any part of the body, are an involuntary contraction in the muscle tissue. Depending on the muscle's size and location, it might be sharp and painful or nearly imperceptible. Technically, a cramp is a kind of muscle spasm that is brief and tends to relax relatively quickly, but the two terms are often used interchangeably. There are many types of spasms and several different underlying causes, so diagnosing repeated episodes is sometimes difficult. An effective treatment might come from physical therapy, dietary changes, medical intervention, or some combination of the three.
How the Muscles Work
Normally, muscles contract and relax according to signals sent by the brain through nerves. This is true of muscles connected to the bones and joints used in work or exercise, as well as those in the stomach and heart that work automatically. A nerve's electrical signal trips a muscle's delicate chemical balance to cause it to either flex or extend.
Why Spasms Happen
Most muscle spasms fall into one of two categories. There may not be enough of certain chemicals necessary for a muscle to function properly, called electrolytes, which can cause nerve signals to not travel correctly. Alternately, the nerve that triggers the muscle might be at fault, whether due to a problem with the nerve itself or with the brain. The common denominator is that the muscle is contracting inappropriately and without the person’s control.
Isolated or brief episodes of spasms are most likely the result of the muscle being injured or strained. At the end of a marathon, for example, runners may be seized with spasms because their body is depleted of water and essential electrolytes. The main electrolytes — conductors of electricity — in the body are potassium, magnesium and calcium. Excess exercise, particularly with poorly conditioned muscles, can also cause them to spasm.
A reaction to some chemicals, such as the poison strychnine, can cause muscles to seize or convulse uncontrollably. The toxins of some venomous animals may produce similar effects by disrupting the function of the nerves. When the nerves are damaged, such as by an injury or a condition like multiple sclerosis (MS), the spinal cord or brain can cause the muscles to spasm.
One of the more familiar muscle spasms is nicknamed a "charley horse." There are several variations and causes for this painful contraction of the calf muscle, but most often, it is due to trauma or dehydration during intense exercise. The crippling effect can last for a few seconds to several minutes. It cannot be relieved by sheer will, but relaxing, breathing and massaging the muscle may help it gradually relax. Fighting the pain of a charley horse will often cause other muscles such as the abdominals to contract as well, prolonging and intensifying the episode.
Stomach cramps are also common. They can be caused by a temporary condition, like a stomach flu infection, or by more serious conditions such as irritable bowel syndrome (IBS). Stomach cramps are also painful, and may be accompanied by nausea and vomiting. The stomach flu usually passes in a few days, although if a patient becomes dehydrated, he or she should seek medical attention. Controlling IBS with diet and medication can reduce its frequency and severity. Infants with the condition called colic have stomach spasms as well, but this is usually their immature brain's response to normal digestion and should improve with age.
Angina is a spasm of the heart muscle, caused when it does not get enough blood. It is associated with atherosclerosis, commonly called a "hardening of the arteries." It is usually felt as a painful tightening of the chest, sometimes expanding to the neck, shoulders and jaw. Medication is often used to treat it, although sudden pain, pain that gets worse, and cramping that lasts for more than 10 minutes may be a sign of a coming heart attack.
The first thing that a person can do to help prevent a muscle spasm is to stay hydrated. Drinking water or other healthy drinks throughout the normal course of a day or when working vigorously will make the muscles less likely to cramp. Good nutrition is also important, and studies have shown that low levels of potassium, calcium and sodium makes muscles more likely to spasm. Many athletes take mineral supplements and will eat a banana, which is rich in electrolytes, an hour prior to working out.
Another consideration is good muscle conditioning with regular exercise and stretches. This is particularly true of injured muscles, which can repeatedly spasm with routine signals from the brain. As the muscle heals with time and gentle therapy, its spasms will typically become less sudden and less frequent.
If preventative measures are not effective, and if a muscle spasm is frequent, the person who is experiencing them should consult a health care provider. A medical professional can investigate whether the patient has been exposed to toxins such as lead or pesticides, and he or she may test for neurological diseases. Medications, including muscle relaxants and pain relievers, may be prescribed for the symptoms.