
High risk of troublesome dyspnea in Mild COPD patients with low resting DLCO during exercise
Patients with mild chronic obstructive pulmonary disease (COPD) and lower resting diffusing capacity for carbon monoxide (DLCO) often report troublesome dyspnea during exercise due to high inspiratory neural drive (IND). A recent study foundĀ that exertional dyspnea is closely linked to relatively high IND due, in part, to the effects of reduced ventilatory efficiency. IND during exercise is relatively high in COPD patients with only mild airway obstruction and lower DLCO. Moreover, the study also presents new evidence that in those with mild COPD and low DLCO, abnormalities of pulmonary gas exchange likely contribute to higher IND from the early stages of exercise. Finally, the higher ventilatory demand in this group likely accelerated development of significant mechanical constraints with further amplification of IND and neuro-mechanical dissociation, which conflated to provoke greater respiratory discomfort as exercise proceeded.