Does the Respiratory System Limit Exercise in Mild Chronic Obstructive Pulmonary Disease?

RATIONALE: It is not known if abnormal dynamic respiratory mechanics actually limit exercise in patients with mild chronic obstructive pulmonary disease (COPD). We reasoned that failure to increase peak ventilation and Vt in response to dead space (DS) loading during exercise would indicate true ventilatory limitation to exercise in mild COPD. OBJECTIVES: To compare the effects of DS loading during exercise on ventilation, breathing pattern, …