DURHAM, N.C. Adding another incentive to exercise, scientists at Duke University Medical Center have found that physical activity improves arthritis symptoms even among obese mice that continue to chow down on a high-fat diet.
The insight suggests that excess weight alone isn't what causes the aches and pains of osteoarthritis, despite the long-held notion that carrying extra pounds strains the joints and leads to the inflammatory condition.
Published Sept. 27 online in the journal Arthritis & Rheumatism, the findings are now being tested in people.
"What's surprising is that exercise, without substantial weight loss, can be beneficial to the joints," said Farshid Guilak, Ph.D., professor of orthopaedic surgery at Duke and senior author of the study. "Ideally, it would be best to be fit and lose a little weight, but this shows that exercise alone can improve the health of your joints."
Even modest improvements could have a major impact if the findings are borne out in people. The Arthritis Foundation reports that one in five adults in the United States have been diagnosed with arthritis, and the annual cost of treating it and other rheumatic conditions has been tabbed at $128 billion.
Many cases of arthritis are associated with obesity and inactivity, so the Duke researchers set out to determine whether a high fat diet induces knee osteoarthritis, and then whether exercise provides a protective effect.
Using two sets of male mice half fed a high-fat diet and the other fed regular chow the researchers noted significant differences among the two groups. The mice on the high-fat food gained weight rapidly, processed glucose poorly and had much higher blood levels of molecules that trigger the chronic inflammation associated with osteoarthritis.
But when these animals got regular running wheel workouts, many of the harmful effects diminished even though the mice ate the same high-fat food an
|Contact: Sarah Avery|
Duke University Medical Center