Predictors of exercise and effects of exercise on symptoms, function, aerobic fitness, and disease outcomes of rheumatoid arthritis

Abstract

Objective: To determine the effects of participation in a low-impact aerobic exercise program on fatigue, pain, and depression; to examine whether intervention groups compared with a control group differed on functional (grip strength and walk time) and disease activity (total joint count, erythrocyte sedimentation rate, and C-reactive protein) measures and aerobic fitness at the end of the intervention; and to test which factors predicted exercise participation.

Methods: A convenience sample of 220 adults with rheumatoid arthritis (RA), ages 40-70, was randomized to 1 of 3 groups: class exercise, home exercise using a videotape, and control group. Measures were obtained at baseline (T1), after 6 weeks of exercise (T2), and after 12 weeks of exercise (T3).

Results: Using structural equation modeling, overall symptoms (latent variable for pain, fatigue, and depression) decreased significantly at T3 (P < 0.04) for the class exercise group compared with the control group. There were significant interaction effects of time and group for the functional measures of walk time and grip strength: the treatment groups improved more than the control group (P <or= 0.005). There were no significant increases in measures of disease activity. Fatigue and perceptions of benefits and barriers to exercise affected participants' amount of exercise, supporting previous research.

Conclusion: This study supported the positive effects of exercise on walk time and grip strength, and demonstrated that fatigue and perceived benefits/barriers to exercise influenced exercise participation. Furthermore, overall symptoms of fatigue, pain, and depression were positively influenced in this selective group of patients with RA ages 40-70 years.