Oh, my aching back!

Low back pain hurts a lot of people and costs a lot of money. Eight out of 10 people experience low back pain at some time in their lives. it is the most common adult disorder of the muscles and bones and is the most frequent cause for limitation of activity in the home and workplace. Low back pain costs billions of dollars annually in lost productivity at work and foregone wages.

How Does It Happen?

Stories vary. Many people relate the onset of low back pain to some particular movement--bending, lifting, pushing, pulling--or some related motion. The onset may be acute, sudden, and dramatic, or it may be almost imperceptibly gradual. Vulnerability to injury seems to be greater with repetitive activities that place stress on the support structures of the lower back. And research reveals that people who are overweight, who smoke, or who are unhappy with their jobs are at greater risk. Curiously, however, many people are unable to recall a specific incident or activity that brought on the pain.

Why Does It Happen?

The cause of low back pain is uncertain, but the most plausible theories indicate that strained muscles and ligaments are responsible for most of the discomfort. It is important to note that pain associated with numbness or weakness of the legs or caused by a direct blow may represent a more serious injury requiring immediate medical evaluation.

What Can Be Done About It?

Moist heat or ice packs? Rest or exercise? Medication or manipulation?

Many creative therapies are prescribed for the relief of low back pain, most without a strong basis in medical evidence. Fortunately, most people with low back pain due to stress or strain recover completely within a few days. Less than 10 percent have persistent pain beyond six to eight weeks. For those whose pain is particularly severe or prolonged, the following counsel regarding specific popular treatments may be helpful.

* Rest. Bed rest is unnecessary, and prolonged bed rest (beyond 48 hours) is detrimental to muscle tone. Sitting erect or standing is more beneficial than lying in bed. It is prudent, however, to avoid activities that are likely to reproduce the pain.

* Medication. Muscle relaxants, tranquilizers, pain pills (singly or combined), are widely prescribed for low back pain. Well-designed studies demonstrate that the benefits of these drugs are questionable and are often outweighed by side effects, such as drowsiness and potential drug dependence. Over-the-counter pain medications, including acetaminophen and ibuprofen, are usually adequate for relief.

* Physical Modalities. Popular but unproven and probably worthless therapies include various kinds of traction and supports, such as corsets and belts. On the other hand, both spinal manipulation and nerve stimulation have proven to be of benefit in certain cases. For most people, warm water applications, gentle massage, and moderate activity are helpful.

* Surgery. Consideration of surgery should be reserved for those with persistent, prolonged pain where conservative treatment has failed, and nerve damage is a concern.

So, if you awaken some morning with a back that hurts a lot, get up, move around a little, take a warm bath or shower, and try a mild analgesic. Chances are good that you will be pain-free and functioning normally within a day or two.

Ted Hamilton, M.D., is medical director Of Florida Hospital Centra Care in Orlando, Florida.