A first principles calculation of the oxygen uptake in the human pulmonary acinus at maximal exercise

► The oxygen capture in a machine acinus, with the geometry and motion of the real acinus, is calculated for peak exercise. ► VO2,max and PAO2, are found to depend in a non-linear manner on the membrane permeability of the machine acinus. ► Only a narrow range of permeability values are compatible with the experimental values of PAO2 and VO2,max at peak exercise. ► These permeability values are significantly smaller than those given in the literature for the usual morphometric value. ► A new evaluation of the diffusive permeability is given compatible with the values found for the machine acinus study.