Evidence for the benefit of aerobic and strengthening exercise in rheumatoid arthritis.

Abstract

Introduction Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease of unknown etiology. It usually presents as symmetric polyarthritis, but also confers general inflammatory symptoms. RA is present in 0.5–1% of the general population, twice as often in women, and the age at disease onset is mainly between 45 and 65 years. The American College of Rheumatology (formerly American Rheumatism Association [ARA]) has suggested diagnostic criteria (1) for RA. The disease course varies and prediction of the prognosis is difficult in any particular case. In the long run, a reduced function, difficulties in activities of daily living (ADL), and a negative psychosocial impact are often seen. RA also is connected with increased risk for osteoporosis (2), cardiovascular disease, and premature death (3). Criteria for the classification of functional loss have been suggested (4). Functional class (FC) I includes individuals without difficulties in daily life, FC II includes those with symptoms but minor limitations only, FC III includes those who are partly dependent, and FC IV includes those who are totally dependent on other persons in daily life. The vast majority of individuals with RA belong to FC II. Pain, stiffness, and fatigue generally occur early in the course of RA. Reduction of body function, such as range of motion (ROM), muscle strength, and aerobic capacity, may follow. As previously summarized by van den Ende et al (5), 50% of patients with RA displayed decreased hand ROM at their first rheumatology visit. Two years later, reduced ROM was found in large joints; the decreased ROM varied between 25% and 35% in different joints (6). Patients with RA and some functional loss (ARA FC II) have been found to have a 25–50% reduction in muscular strength compared with age-matched healthy controls (7– 10), and 55% deficit in muscular endurance (9). In patients with more serious RA, reductions of muscular strength up to 70% have been reported (11). Patients taking long-term oral steroids have a more pronounced loss of muscle strength (12,13). Reduced muscle function in patients with RA may also present itself as loss of functional balance and coordination (14). Among patients with RA who were able to perform bicycle ergometer tests, the aerobic capacity was reduced by 20–30% (7,9,15,16). The aerobic capacity is probably even lower among those who are not able to perform such tests. A portion of the reduced physical capacities found among individuals with RA may be attributed to inadequate levels of physical activity. The treatment of RA focuses on decreasing inflammatory activity and symptoms, limiting joint destruction and disability, and improving health related quality of life. It includes a rich variety of medication, surgery, and rehabilitation. Despite earlier fear of aggravation of symptoms, increased disease activity, and joint destruction, there is now scientific support that various forms of exercise are both safe and beneficial (17). Exercise has become an important part of rehabilitation during the last decades. A number of studies of various quality have been carried out to investigate the effects of aerobic and strengthening exercise in RA, but no recent reviews have been published. The aim of the present study was to investigate the evidence for the benefit of aerobic and strengthening exercise in RA.