The Effect of Added Dead Space on the Pulmonary Response to Exercise

The effect of an increase in respiratory dead space on the ventilation during exercise was studied in 4 normal subjects breathing through a mixing chamber of variable volume at one or more work loads. The resulting increases in ventilation and alveolar Pco2 were dependent on the work load and the volume of added dead space. The magnitude of the changes were related to the subject’s ventilatory response to CO2, as measured at rest. The level of exercise, CO2 output, or volume of dead space did not appear to have independent effects on the ventilatory response.