People with arthritis don’t exercise enough, and more than a third of adults with arthritis don’t exercise at all, according to a study in the May issue of American Journal of Preventive Medicine.

“People with arthritis are not meeting physical activity recommendations made at the federal level and by experts in the arthritis field,” said co-author Jennifer Hootman, Ph.D., of the Centers for Disease Control and Prevention. “That’s not good, because we know that being more active is beneficial for arthritis.”

While exercise has been shown to decrease their pain, delay disability and improve gait and function, people with arthritis are even more likely to be inactive than adults in the general population.

“These findings are not surprising,” said Kate Lorig, a professor at the Stanford University School of Medicine, who was not involved with the study. “What’s important for people with arthritis to realize is that the most dangerous type of exercise is not to do any.”

Hootman and colleagues reviewed data from the 2002 National Health Interview Survey, an ongoing household survey designed to be representative of the U.S. population. The survey included 6,829 people who had been diagnosed with arthritis and 20,676 people without arthritis.

Just 37 percent of adults with arthritis met the least stringent physical activity guidelines established by a panel of experts in arthritis, physical activity and public health in 2001 -  a percentage similar to people without arthritis.

But participation rates at the more rigorous federally recommended levels of physical activity were even lower for people with arthritis -  30 percent compared with 33 percent for people without arthritis.

Twenty percent of people with arthritis reported performing some type of activity to strengthen their muscles. Both aerobic and strengthening exercises have been shown to help people with arthritis.

People with arthritis least likely to be physically active were those who had difficulty walking up ten stairs, grasping small objects, bending or kneeling, lifting ten pounds or standing for two hours.

“We can’t tell from this survey which came first - the inactivity or the problems with function,” said Hootman. “But we do know that getting people with arthritis active actually improves function.”

The authors say that fear of pain and the misconception that exercise can harm joints are obstacles to getting people with arthritis to exercise.

Other risk factors for inactivity among people with arthritis included frequent anxiety or depression, especially among women, and severe joint pain among men.

“If we can get people with arthritis over the initial pain barrier by addressing their pain and getting them more active, they’ll actually have less pain in the long term,” Hootman said.

Shih M, et al. Physical activity in men and women with arthritis. Am J Prev Med 30(5) 2006.