Pulmonary Rehabilitation: Mechanisms of Functional Loss and Benefits of Exercise.

Exercise limitation is a characteristic feature of chronic respiratory diseases such as COPD and is associated with poor outcomes including decreased functional status and health-related quality of life and increased mortality. The mechanisms responsible for exercise limitation are complex and include ventilatory limitation, cardiovascular impairment, and skeletal muscle dysfunction. In addition, comorbidities such as cardiovascular disease are common in this population and can further impact exercise capacity. Exercise training, a core component of pulmonary rehabilitation, improves exercise capacity by addressing many of these mechanisms that, in turn, can potentially slow the decline of lung function, reduce the frequency of exacerbations, and decrease mortality. This article will discuss the mechanisms of exercise limitation in individuals with chronic respiratory disease, primarily focusing on COPD, and provide an overview of exercise training and its benefits in this patient population.