Pathophysiologic changes observed during exercise in pulmonary disorders

Abstract

Chronic pulmonary disease is common in the community and increasing in prevalence. Although numerous etiologies exist, chronic obstructive pulmonary disease (COPD) is mainly secondary to tobacco smoking. The detrimental outcomes of these diseases in patients is disabling breathlessness and impairment of functional exercise capacity. The symptoms set up a vicious cycle leading to physical deconditioning and worsening exercise performance. The pathophysiological hallmark of COPD is expiratory flow limitation. When ventilation increases in flow-limited patients during exercise, air trapping is inevitable and causes further dynamic lung hyperinflation (DH) above the already increased resting volumes. Interstitial lung disease (ILD) causes alveolar and capillary destruction which decreases compliance, increases work of breathing, increases pulmonary vascular resistance, and limits venous return.