Women tend to have smaller lungs than men of the same size as well as narrower airways compared to men when matched for the same lung size. Additionally, women with smaller airways relative to lung size are more likely to experience expiratory flow limitation (EFL) as well as exercise-induced arterial hypoxemia (EIAH). One of the possible causes of EIAH includes excessive widening in the alveolar-to-arterial oxygen pressure difference (A-aDO2) due to diffusion limitation