Nutritional Rehabilitation in Chronic Obstructive Pulmonary Disease (COPD) Patients With Muscle Atrophy

To study in clinically stable Chronic Obstructive Pulmonary Disease (COPD) patients with muscle atrophy: 1. The short-term effects of 4 months exercise training including nutritional supplementation versus exercise training alone on physical functioning (skeletal muscle strength and exercise capacity) and body composition. 2. The long-term effects of 4 months of exercise training and nutritional supplementation followed by 8 months of nutritional counseling (with supplementation on advice) and feedback on physical activity level versus 4 months of exercise training and 8 months with feedback on physical activity level alone on physical functioning, body composition and cardiometabolic risk profile; 3. The cost-effectiveness of exercise rehabilitation and nutritional intervention versus exercise rehabilitation alone.