Effects of industrial respirators on pulmonary functions and ability to perform metabolic work

Four subjects were used to demonstrate the effects of wearing industrial respirators on pulmonary physiology and ability to perform metabolic work. Work was performed on a bicycle ergonometer. Pulmonary volumes and pressures were measured, as were inspiratory and expiratory work rates and oxygen consumption. It was demonstrated that the inspiratory work rate increased with increased inspiratory resistance and with increased respiratory minute volume; that respiratory resistance had no consistent effect on oxygen consumption at any given metabolic work rate; that increased inspiratory resistance causes increased use of both inspiratory and expiratory muscles; and that, although each subject responded consistently to an inspiratory resistance, there was considerable variation among subjects.