Ventilatory decline after hypoxia and hypercapnia is not different betweenhealthy young men and women

The gradual decay in ventilation after removal of a respiratory stimulus ha s been proposed to protect against cyclic breathing disorders such as obstr uctive sleep apnea (OSA). The male predominance of OSA, and the increased i ncidence of OSA in women after menopause, indicates that the respiratory-st imulating effect of progesterone may provide protection against OSA by alte ring the rate of poststimulus ventilatory decline (PSVD). It was therefore hypothesized that PSVD is longer in premenopausal women than in men and is longer in the luteal menstrual phase compared with the follicular phase. PS VD was measured in 12 men and in 11 women at both their luteal and follicul ar phases, after cessation of isocapnic hypoxia and normoxic hypercapnia. P SVD was compared between genders and between women in the luteal and follic ular phases by repeated-measures AN OVA. There were no significant differen ces in PSVD between any of the groups after either respiratory stimulus. Th is suggests that the higher occurrence of OSA in men does not reflect an un derlying gender difference in PSVD and implies the increased prevalence of OSA in women after menopause is not representative of an effect of progeste rone on PSVD.