If your back hurts -- and for seven of 10 Americans it sometimes does -- the cure may be as simple as putting one foot in front of the other. Walking can lessen pain, hasten healing, boost strength, increase flexibility, and, in the long run, prevent recurrences.

Need proof? A 2004 study in The Spine Journal showed that a single session of an exercise such as walking can reduce low back pain 10 to 50 percent. And a 1993 study found that just 10 minutes of treadmill walking led to a significant reduction in back pain.

"Walking is one of the simplest things you can do for yourself," says Dr. Dave Drake, director of musculoskeletal and sports medicine at Virginia Commonwealth University in Richmond.

Typically, the cause of back pain is a muscular strain or spasm brought on by lugging around heavy objects. But sometimes it strikes with no noticeable cause. The pain usually lasts a few days or weeks, but if the injury involves compressed nerves or spinal discs, the hurt can last months, or even years.

Walking works because it stimulates the brain to release serotonin and endorphins, neurotransmitter chemicals that make you feel better physically and mentally. Walking also blocks pain through distraction. This is known as the gate control theory of pain: When you work the big muscle groups in the trunk and legs -- muscles with correspondingly large nerves -- the signals fired to the brain literally overload pain messages coming from smaller nerves.

"Start out slow and easy and gradually build up speed and distance," says Dr. Jeff Susman, chair of family medicine at the University of Cincinnati.

Walk around the block, stroll the mall, or start off on a treadmill. Always walk on a flat surface while you're healing, because hills force you to lean forward and strain the lower back. Be prepared for some discomfort -- at first. "It sounds paradoxical, but it's better to work through the pain," Susman says.

However, if walking gives you shooting leg pain or numbness, stop and see a doctor.

Originally published in Better Homes and Gardens magazine, April 2005.