COPD is a progressive and debilitating disorder for which impaired quality of life is a hallmark. A cardinal factor that contributes to impaired quality of life in COPD is exercise intolerance. Exercise intolerance promotes limb weakness and social isolation and contributes to a feeling of helplessness, factors that all contribute to a decrease in quality of life. Exercise intolerance in COPD has been attributed to worsened airflow obstruction, impaired gas exchange, and skeletal muscle weakness; however, data point to lung hyperinflation as the most important factor that contributes to exercise impairment in COPD.1 Lung hyperinflation plays a central role in impairing respiratory muscle and chest wall mechanics, which increases breathlessness; limiting successful weaning from mechanical ventilation; decreasing exercise performance; and, most importantly, leading to a higher rate of mortality. Casanova and colleagues2 demonstrated in > 689 patients with mild-to-severe COPD that an inspiratory capacity (IC)-to-total lung capacity (TLC) ratio ≤ 0.25 was associated with a twofold increase in mortality over a 4-year follow-up period compared with patients with an IC/TLC > 0.25. The cause for higher mortality in patients with an IC/TLC ratio ≤ 0.25 was not clear in this study, but these patients subsequently have been reported to have decreased peak oxygen consumption during maximum exercise3 and decreased resting and peak exercise O2 pulse.4 The reductions in O2 pulse at rest and during peak exercise suggest decreased cardiac performance in patients with severe lung hyperinflation that is signified by an IC/TLC ≤ 0.25.