Airway size and its association with exertional dyspnea in healthy males and females

The large conducting airways are smaller and the perception of dyspnea at a given absolute minute ventilation (V̇ E) is higher in females than in males. We sought to determine whether sex differences in airway luminal area are related to sex-differences in exertional dyspnea. We hypothesized that: i) large conducting airways luminal area would be smaller in females than in males, and ii) that the perception of dyspnea during exercise would be significantly related to airway-to-lung (i.e., dysanapsis) ratio. We analyzed data from n=104 healthy ≥40 y old never smokers enrolled in the Canadian Cohort Obstructive Lung Disease (CanCOLD) study who underwent pulmonary function testing, a chest computed tomography scan, and a cardiopulmonary exercise test. The luminal area of the trachea, right main bronchus, left main bronchus, right upper lobe, bronchus intermedius, left upper lobe, and left lower lobe were smaller (22-37%; all p0.05). Our findings suggest that 44 sex-differences in airway size do not contribute to sex-differences in exertional dyspnea.