Aerobic exercise, strength training, and their variants in rheumatoid arthritis (RA) have been studied in controlled trials since 1975 (1). In theory, exercise prevents the vicious cycle of joint pain leading to joint stiffness, soft tissue contracture, diminished muscle strength and endurance, and loss of independence. Although these trials differ with respect to the duration and frequency of exercise, the types of patients studied, the specifics of the exercise regimen, and the end points used, some generalizations can be made. Regular prolonged exercise improves aerobic capacity, muscle strength, joint mobility, functional ability, and mood by as much as 57%, without apparent increases in joint symptoms or disease activity (2). The American College of Rheumatology recommends strengthening and aerobic conditioning regimens in its guidelines for the management of RA (3). Experienced patients with RA advocate exercise as part of disease self-management (4).
The report in this issue of Arthritis & Rheumatism by de Jong et al (5) is a well-controlled evaluation of the effectiveness and safety of a long-term exercise program compared with usual therapy. The exercise program studied was a high-intensity program including classic aerobic and strengthening exercises and impact sporting activities, the latter of which are not usually engaged in by patients with structural damage in the hip and knee joints (6). It is only the second controlled study assessing safety of exercise by followup radiographs of involved joints, and 1 of only 5 studies that include radiographic progression as an end point (Table 1). Both controlled studies show a trend toward more progressive joint damage in the exercise intervention groups. In the study by de Jong et al (5), more joint damage progression was observed in patients in both groups who started with more structural damage and longer disease duration. This progression was more apparent in the exercise group, despite the fact that, on average, the patients in this group had some markers of less serious disease at baseline, such as less structural joint damage, shorter disease duration, and fewer medication requirements. All studies that examined radiographic outcomes of exercise were underpowered to show differences in structural changes of the joints, since this was not their primary end point. Three additional nonrandomized studies cannot be interpreted with regard to joint damage, since the self-selection of exercise might be related to milder disease (Table 1).
|Author, year (ref.)||Duration, years||No. of patients||Difference in Larsen change scores between exercise and control groups†||P|
|Randomized controlled trials|
|De Jong et al, 2003 (5)||2||293||+0.3‡||0.134|
|Hansen et al, 1993 (7)||2||65||+3 to +11§||NS|
|Nordemar et al, 1981 (8)||4–8||46||−2.8‡||0.025|
|Stenstrom et al, 1991 (9)||2||30||NR||NS|
|Stenstrom, 1994 (10)||4||46||−12‡||NS|
These findings may increase reservations that clinicians have about prescribing exercise for patients with RA. Approximately 58% of rheumatologists in an arthritis center believe aerobic exercises are not useful for RA patients (11). There is a spectrum of studies addressing the consequences of repetitive joint loading. On the one hand, there are experiments of nature and clinical studies that suggest that allowing acutely inflamed joints to rest reduces local and systemic signs of inflammation (12, 13), although the price may be some increased joint stiffness. On the other hand, controlled studies suggest that exercise improves symptomatology and function (for review, see ref.2). Case reports and observational studies suggest that patients who participate in rigorous physical activity or occupations with heavy manual work (those with “robust-type RA”) have more aggressive erosive disease (14). Patients with RA who performed heavy manual work also lost physical function sooner (15).
What is one to make of all this? First, one cannot ignore the benefits of exercise in improving functional independence and quality of life of persons with RA. Regular physical activity also lowers blood pressure and reduces cardiovascular risk, both of which are useful in patients with RA, since they are at higher risk of cardiovascular disease. Second, good studies raise new questions. As with all therapies, there is no benefit without possible side effects. Exercise prescription is no exception. Exercise may not increase symptoms of disease activity in RA in the short run (2 years is a relatively short period in a chronic illness), but it may still carry a long-term risk of articular damage, particularly in patients with uncontrolled synovitis. Arthritis symptoms don't match well with structural joint damage. A major research question is whether there is a long-term risk conferred by exercise in RA, particularly with activities that involve joint loading (such as running). These studies would have to be powered to show safety, which implies larger sample sizes and quality control of radiographic assessments to detect small differences in joint space width and erosions.
Clinically, these studies suggest caution in prescribing exercise to patients who already have significant joint damage, especially of weight-bearing joints. High-impact exercise might be relatively contraindicated, and, if exercise is prescribed, it should involve modalities that don't load the joint, such as water walking, swimming, biking, rapid walking, or strengthening. In cardiovascular risk prevention, recommendations have changed from high-intensity aerobic exercise to regular physical activity (a total of 30 minutes a day, 3 times a week), since both seem to confer similar cardiovascular benefits (16). From a practical point of view, these latter recommendations tend to be better accepted and sustained over the long run. There may be lessons in this for the management of RA, as well. Specifically, this would mean encouraging RA patients to follow these guidelines and to be as physically active as possible. Patients should try different activities to find those they enjoy and are able to maintain without increasing joint symptoms. They should expect to “fail” or to be bored occasionally. (That's okay!) Having a variety of physical activities options, building activity into their routines, and doing this with friends helps patients to develop a lifestyle, in contrast to following their providers' prescriptions. At this point, prudence would suggest discouraging high-impact loading activities in patients with structural damage.