Conventional pulmonary rehabilitation programs improve exercise tolerance, peripheral muscle strength, and health related quality of live but not pulmonary function in patients with chronic obstructive pulmonary disease (COPD). The role of breathing retraining techniques in the rehabilitation of patients with COPD remains unclear. The hypothesis to be tested in this study is that pulmonary function, cardio-pulmonary exercise capacity, health related quality of life and cardiac autonomic modulation of patients with COPD who undergo pulmonary rehabilitation plus breathing retraining will be better than that of patients undergoing a conventional pulmonary rehabilitation.

To address this uncertainty, we performed a randomized controlled trial to assess the effects of a 4-week rehabilitation program including breathing retraining on pulmonary function (PFT), cardio-pulmonary exercise capacity (CPET), health related quality of life (HRQL) and cardiac autonomic modulation (CAM).

A randomized controlled trial comparing the effects of a conventional 4-week pulmonary rehabilitation program with those of a 4-week pulmonary rehabilitation program plus breathing retraining on pulmonary function (FEV1), cardiopulmonary exercise capacity (6-minute walking distance, 6MWD), health related quality of life (chronic respiratory questionnaire, CRQ) and cardiac autonomic function (rMSSD) was performed.

Inclusion Criteria:

• Clinically stable patients with COPD (GOLD-classification I-IV)

Exclusion Criteria:

• Patients with clinical signs of COPD exacerbation
• Cardiac arrhythmia
• Coronary artery disease
• Primary pulmonary vascular disease
• Oxygen desaturation to less than 80% during exercise on room air