Chronic obstructive pulmonary disease (COPD) is one of the most frequent causes of death in the United States. Patients with COPD nearly always have a long history of cigarette smoking. The irritants in cigarette smoke cause inflammation of the airways, which leads to obstruction of airflow in and out of the lungs. Poor airflow causes patients to have shortness of breath, especially during exercise. The lung damage from cigarette smoke is usually permanent, so drugs are only partially effective in improving air flow. However, exercise training can reduce shortness of breath even in severe COPD. Many hospitals have programs that provide closely supervised exercise training in the hospital setting. However, access to these programs is limited. Only a small fraction of patients with COPD are able to get exercise training.