© 1990S. Karger AG. Basel 0025-7931/90/0574-0264 S 2.75/0

Respiration 1990:57:264-267

C 0 2Chemoreflex Drive of Ventilation in Man : Effects of Hyperoxia and Sex Differences' P. Sebert. L. Barthélémy, P. Mialon Service d'Explorations Fonctionnelles Respiratoires Lavoisier. CHU A. Morvan, Brest, France

Key Words. C 0 2test • Regulation of breathing • Peripheral chemoreceptors • Hyperoxia • Sex differences • Ventilatory chemoreflexes • Hypercapnia Abstract. C 0 2single breaths have been performed in 7 men and 7 women in conditions of normoxia (FICOs = 0.13; F I0 2 0.21; F1N2 = 0.66) and of hyperoxia (FIC 02 = 0.13; F102 = 0.87). Ventilatory responses of the subjects and modifications of breathing pattern in the course of the C 0 2tests were also explored in the two con­ ditions. The results (mean±SEM) show that, whatever the oxygenation, men and women exhibit the same ventilatory response during a C 0 2 test from a qualitative point of view but with a smaller intensity in women (men: 0.37 ± 0.088 L Btps • m in'1• Torr'1; women: 0.15 ±0.025 L BTPS • m in'1• Ton"1; p