Investigation of Muscle Oxygenation in Patients With Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic progressive autoimmune disease of unknown etiology with symmetric erosive synovitis and multisystem involvement. The disease causes significant long-term morbidity, reduced functional capacity, and increased mortality rates. Patients with rheumatoid arthritis avoid physical activity due to pain and fatigue. Despite the advances in pharmacological treatments in recent years, functional losses due to rheumatic diseases the resulting deterioration in quality of life, and loss of work continue. Physical inactivity is known to have detrimental effects on the cardiovascular and pulmonary systems by reducing muscle strength and aerobic capacity. The physiological reasons underlying skeletal muscle oxygenation that may cause muscle dysfunction in rheumatoid arthritis have not been investigated. In these patients, decreased arterial oxygen may reduce exercise capacity and cause muscle deoxygenation. In rheumatoid arthritis patients, decreases in respiratory muscle strength, lung volumes, oxygen consumption, and six minute walk test distance cause cardiopulmonary deconditioning. Decreased exercise capacity increases the risk of cardiovascular disease and causes mortality in patients with RA. This study aimed to, the effects of respiratory muscle strength, respiratory muscle endurance, upper and lower extremity muscle oxygenation, and upper and lower extremity exercise capacity in patients with stable disease activity.