Women with rheumatoid arthritis performed 1 of 3 low intensity aerobic exercise protocols (15, 25, and 35 minutes) 3 times per week for 12 weeks. A nontraining group served as controls. All exercise groups improved their aerobic capacity, exercise time, and joint counts. Subjects described improvement in activities of daily living and reduced joint pain and fatigue. Exercise duration up to 35 minutes can be therapeutic, and as little as 15 minutes of exercise 3 times/week is sufficient to improve aerobic capacity in rheumatoid arthritis patients with severe limitations.