Nov. 13 (HealthDay News) -- Exercise may seem best at preventing illness rather than treating it, but a new study suggests that low-impact physical activity could make an immediate difference for people with one tough-to-treat condition: fibromyalgia.

Women with the little-understood chronic pain syndrome who exercised moderately for four months reported feeling better in a number of ways.

The study didn't say how much more likely the women were to feel better after adopting an exercise regimen, and it's not clear how long the effects last. Still, the findings are promising, said study lead author Daniel S. Rooks, an assistant professor of medicine at Harvard Medical School.

"Exercise should become a part of the treatment plan for people with fibromyalgia," Rooks said. "Basic, simple walking, starting slow and gradually improving, as well as basic flexibility training should be part of what people do to help themselves."

Fibromyalgia causes intense pain and can produce fatigue, insomnia and other symptoms. An estimated 3.5 percent of U.S. women suffer from the syndrome, compared to 0.5 percent of men.

There has been much debate about fibromyalgia, particularly over the role that mental health may play in its progression. Treatment options include pain medications, antidepressants and counseling.

Doctors often recommend exercise as a treatment, but it hasn't been clear exactly what kinds of physical activity should be recommended, Rooks said.

Enter the new study, in which researchers looked at the experiences of 135 women with fibromyalgia from 2002-2004 who were assigned to one of four groups, three of which consisted of exercise regimens.

The researchers gave questionnaires to the women about the state of their fibromyalgia, both before they began the four-month exercise programs and after they completed them. Those who took part in strength training, aerobic activity, and flexibility training -- along with a self-help course on managing fibromyalgia -- reported the most significant improvement, the study found.

Women also improved after taking part in just flexibility and aerobic exercise or in all the three types of activity but without the self-help course. Those who just took the course noted the least improvement.

"Everybody improved if they exercised," Rooks said. "Everybody had some improvement in some aspect of things we were testing."

The study was published in the Nov. 12 issue of Archives of Internal Medicine.

The exercise levels required in the study, which was funded by the Arthritis Foundation and U.S. National Institutes of Health, were moderate and didn't require sweating, Rooks said. "Part of the message is that you didn't have to work like you were training for the marathon to improve your health," he said. "That was an important message we tried to communicate throughout the study. It was a very well-received message."

There were other benefits of exercise, too. Social function, mental health, fatigue and depression also improved, the study authors wrote. The beneficial effect on physical function of exercise alone and in combination with education persisted at least six months.

Why would exercise be so helpful? "There is a physical part of it and an emotional part of it," Rooks said. "It gives people confidence that they can use their muscles when people have been telling them not to use their muscles."

Dr. Roland Staud, professor of medicine at the University of Florida and a fibromyalgia expert, said exercise is crucial for improvement in patients with chronic pain.

He called Rooks' study well done, if small, and said it shows the value of aerobic exercise in particular. "A lot of fibromyalgia patients think exercise creates more pain, and that wasn't shown here."

SOURCES: Daniel Rooks, Sc.D., assistant professor of medicine, Harvard Medical School, Boston; Roland Staud, M.D., professor of medicine, University of Florida, Gainesville; Nov. 12, 2007, Archives of Internal Medicine