In order to evaluate the possible effects of respiratory muscle training in patients with neuromuscular disease, we examined the cardiopulmonary response in 13 patients and 17 healthy controls by recording flow volume curves, ECG and alveolar carbon dioxide levels and collecting mixed expiratory air in Douglas bags. The cardiopulmonary response of our patients was not significantly different from that of the controls, and therefore we see no reason to avoid muscle training in patients with such disease.