Physical activity is an important part of managing diabetes symptoms. However, a new study says that more than half of adults with diabetes also have arthritis, which can keep them from exercising.

The research, conducted by the U.S. Centers for Disease Control (CDC), indicated that more than 46 million American adults have arthritis, and 20.6 million suffer from diabetes. About 52 per cent of adults who have diabetes also have arthritis.

Of those who have both arthritis and diabetes, almost 30 per cent did not participate in physical activity. Twenty-one per cent of people who had only diabetes were inactive, and more than 17 per cent of people with arthritis were inactive.

"The associations between arthritis and physical inactivity among adults with diabetes found in this analysis suggest that arthritis might be a barrier to being physically active in this population," the study's authors wrote.

"Being more physically active (e.g., through aerobic exercise or strength training) can benefit persons with either arthritis or diabetes and those with both conditions."

The authors suggest that activities that are easy on the joints, such as walking, swimming and biking, can in fact ease the symptoms of both ailments.

"These findings suggest more needs to be done to help people with diabetes and arthritis get physically active to improve their health," Dr. Chad Helmick, a CDC medical epidemiologist and co-author of the study, said in a statement.

"Engaging in regular physical activity and maintaining a healthy weight can help alleviate the pain and disability that often accompany arthritis."

In their study, the authors said that people who have diabetes or arthritis may choose to avoid physical activity because they are afraid of aggravating their conditions. They go on to suggest that doctors need to ensure that they include physical fitness counselling as part of the care they provide to diabetic and arthritic patients.

As well, disease-management classes offered through hospitals and community health organizations may help get these patients moving.

"We know it can be difficult, but regular physical activity helps in many ways," Janet Collins, director of the CDC's National Center for Chronic Disease Prevention and Health Promotion, also said in a statement.

"For people with diabetes, physical activity helps control blood glucose and risk factors for complications. For people with arthritis, physical activity reduces pain, and improves function."

The study, entitled 'Arthritis as a Potential Barrier to Physical Activity Among Adults with Diabetes: United States, 2005 and 2007,' was published in Thursday's edition of the CDC's Morbidity and Mortality Weekly Report.