All patients will have a diagnosis of COPD according to the global initiative for chronic obstructive lung disease (GOLD) criteria. The patients will be at a stable phase of the disease, indicated by a lack of change in medical therapy (including oral steroids) or an exacerbation of symptoms in the preceding 4 weeks. Patients with other known severe chronic diseases, including cardiac, neuromuscular, or orthopedic disorders, will be excluded.
