Changes in Response to Inhalation of CO2 Before and After 24 Hours of Hyperventilation in Man

Abstract
Respiratory ventilation responses to CO2-O2 mixtures before and after 14 hrs. of hyper-ventilation in a body respirator were detd. on 3 young, healthy, male medical students. Two of the subjects showed an increase in ventilation response to the 3 concns. of CO2 (2.5%, 5%, and 7.5% CO2 in oxygen)after the hyperventilation, while the 3d exhibited an increase in response to the highest concn. of CO2 but not to the 2 lower concns. Stimulus response curves, constructed by plotting alveolar pCO2 against alveolar ventilation ratio, showed an increase in slope in 2 of the 3 subjects when responses after 24 hrs. of hyperventilation were compared with responses before hyperventilation.