Exercise limitation in COPD

Exercise tolerance is reduced across all stages of chronic obstructive pulmonary disease (COPD) and this is coupled with numerous negative outcomes. Exercise-limiting factors in patients with COPD can be summarized as 1) imbalance between ventilatory capacity and demand, 2) imbalance between oxygen supply to respiratory and peripheral muscles and demand and 3) peripheral muscle dysfunction. This clinical review article addresses the phenomenon of the impaired exercise capacity in COPD, explores the main underlying pathophysiological mechanisms and attempts to provide the reader with an overview of the way these mechanisms intergrade to generate this deleterious effect.