Exercise is perhaps the most important of these, whether it is some form of stretching, isometrics, or simple endurance exercise. Exercise prevents the muscles from shrinking. Inactivity encourages both loss of muscle tone and bone deterioration. Too much exercise, however, will cause more pain in those with rheumatoid arthritis or osteoarthritis. One form of exercise that's effective and soothing is hydrotherapy, or movement done in water.
Doctors highly recommend swimming, too.
But remember, hydrotherapy, or any form of exercise, should never produce pain. If you begin to hurt, stop and rest or apply ice packs. Keep movements gradual, slow, and gentle. If a joint is inflamed, don't exercise it. Don't overdo it.