Ventilatory control in normal man following five minutes' exposure to hypoxia.
Ventilatory control was studied in normal subjects following brief (5 min) exposure to hypoxia (inhalation 7-8% O2). The ventilatory response to rebreathing CO2 (hyperoxic) was assessed 20 min before and after 5 min exposure to (a) 7-8% O2, (b) 7-8% O2 rebreathing CO2, (c) rebreathing CO2 during hyperoxia, and (d) 10% O2, normocapnic. The slope of the V-PCO2 response (S) was increased for up to 40 min following (a) and (b) by 25-34%, but was unchanged following (c) and (d). Resting ventilation was unchanged throughout. The ventilatory response to normocapnic progressive hypoxia was measured as the slope of the V-Hb% SaO2 relationship (H); this was increased by 26%. The mechanism underlying this change in ventilatory control in man is unknown; it may relate to the process of acclimatization to hypoxia whereby chronic hypoxia is a greater stimulus to ventilation than acute hypoxia.
D000064:Acclimatization; D000328:Adult; D002319:Cardiovascular System / Q000503:physiopathology; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D010100:Oxygen / Q000097:blood; D012119:Respiration; D012146:Rest; D013997:Time Factors
D006454:Hemoglobins; D010100:Oxygen