Fig. 7From: Respiratory consequences of N95-type Mask usage in pregnant healthcare workers—a controlled clinical studyPulmonary gas exchange in pregnant women at rest and following exercise. O2 and CO2 concentrations were measured with a metabolic cart to calculate volumes of oxygen (a) VO2, or carbon dioxide (b) VCO2 exchanged with each breath. N = 19 (±SEM)Back to article page