Physical Training Fails to Improve Ventilatory Muscle Endurance in Patients with Chronic Obstructive Pulmonary Disease

Abstract

We examined the effect of arm and leg exercise training on ventilatory muscle performance in 15 patients with symptomatic COPD. Eight patients trained their arms while seven trained their legs for six weeks. Before and after the training we measured exercise and pulmonary function including the maximal sustained ventilatory capacity (MSVC). After training there was no significant change in spirometric values and lung volumes. The mean endurance workload performed for 20 minutes increased significantly in both the arm and leg trained groups (14.4 +/- 2.4 to 24.8 +/- 2.5 W, P less than 0.01, and 26.1 +/- 2.4 to 44.4 +/- 2.5 W, P less than 0.01, respectively). Despite the increase in endurance, no significant change was noted in the MSVC (46 +/- 5 to 51 +/- 5 for the arm trainers and 36 +/- 2 to 39 +/- 1 for the leg trainers). We conclude that nonventilatory muscle exercise such as arm and leg cycling does not improve ventilatory muscle endurance, and that increased exercise endurance may occur independent of changes in ventilatory muscle endurance.