1. Pulmonary Rehabilitation Unit, Morlaix Hospital Centre, Morlaix, France;
2. European University of Occidental Brittany, EA3878, Brest, France;
3. Institut de Recherche Expérimentale et Clinique (IREC), Pôle de Pneumologie, ORL & Dermatologie, Université Catholique de Louvain, Brussels, Belgium;
4. Department of Internal Medicine and Chest Diseases, EA3878 (G.E.T.B.O.), CIC INSERM 0502, University Hospital of Brest, European University of Occidental Brittany, Brest, France;
5. Service de Pneumologie, Cliniques Universitaires Saint-Luc, Brussels, Belgium