Women experience fluctuating orthostatic intolerance during the menstrual cycle, suggesting sex hormones may influence cerebral blood flow. Young (aged 18-30) healthy women, either taking oral contraceptives (OC; n = 14) or not taking OC (NOC; n = 12), were administered hypercapnic gas (5%) for 5 min in the low hormone (LH; placebo pill) and high hormone (HH; active pill) menstrual phases. Hemodynamic and cerebrovascular variables were continuously measured.
View Article and Find Full Text PDFProgesterone and its analogues are known to influence ventilation. Therefore, the purpose of this study was to investigate the role of endogenous and pharmaceutical female sex hormones in ventilatory control during the activation of the metaboreflex, mechanoreflex, and CO chemoreflex. Women aged 18-30 taking (n = 14) or not taking (n = 12) oral contraceptives (OC and NOC, respectively) were tested in the low hormone (LH) and high hormone (HH) conditions corresponding to the early follicular and mid-luteal phases (NOC) or placebo and high-dose pills (OC).
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