Inclusion Criteria:  COPD diagnosis following American Thoracic Association (Am Rev Respir Dis 1987;136:225-244), FEV1/FVC < 70% (FEV1: forced expiratory volume in one second, FVC: forced vital capacity) post-bronchodilator. Acceptation to participate in the study by the informed consent.  Exclusion Criteria:  Concomitant diseases that could interfere in the realization of the measures in the study (dementia, severe psychiatric disease, invalidating neurological diseases, important deafness, active neoplasms); patients with asthma as main diagnostic; patients with bronchiectasis as main disease or with extensive sequels of pulmonary tuberculosis; patients that in the beginning seem to be unable to follow the procedures of the study (questionnaires, pulmonary function test, 6 minutes walking test…); patients with difficulties to walk; patients with active infections or chronic inflammatory diseases; patients that reuse to participate in the study.