Inclusion Criteria:  Patients clinically stable Optimised medical therapy Patients who perform pulmonary rehabilitation for the first time Postbronchodilator FEV1 < 60% pred and FEV1/forced vital capacity (FVC) < 70% whithout significant reversibility (< 15% change un unutial FEV1)  Exclusion Criteria:  Clinical evidence of exercise limiting cardiovascular Clinical evidence of neuromuscular diseases