Key result
In premenopausal women without contraception, hypoxic ventilatory response at exercise was higher in the early luteal/midluteal phase than in the early follicular phase (0.89 vs 0.75 mL/[min·kg]; p=0.03).
Why the study?
Tolerance to high altitude in women may be influenced by hormonal status because female hormones modulate ventilation.
Does hormonal status (menstrual cycle, oral contraception, menopause) influence ventilatory and cardiac responses to hypoxia and tolerance to high altitude in women?
Observational (n=1,060)
Does hormonal status (menstrual cycle, oral contraception, menopause) influence ventilatory and cardiac responses to hypoxia and tolerance to high altitude in women?
Absolute Event Rate: 0.89% vs 0.75%
p-value: p=0.03
Physiological responses to hypoxic exercise in women depend on the ovarian cycle phase and aging, but oral contraception and hormonal treatment do not influence tolerance to high altitude.
Hormonal status may modulate women's hypoxic responses; leaves open effects on altitude tolerance pending prospective validation.
Introduction: Tolerance to high altitude in women might be influenced by hormonal status since female hormones modulate ventilation. Methods: Our objectives were (i) to explore in 1060 women, the influence of the phase of menstrual cycle, oral contraception, and menopause with or without hormonal treatment, on hypoxic ventilatory response at exercise (HVRe) and hypoxic cardiac response at exercise (HCRe) measured during a routine hypoxia exercise test, before an exposure to high altitude; (ii) to determine in 260 women exposed to high altitude, the influence of menopause and oral contraceptive and other drug use, on the prevalence of severe acute mountain sickness (sAMS). Four groups were defined: premenopausal with or without oral contraception and postmenopausal with or without hormonal treatment. Results: In premenopausal women without contraception, HVRe was higher in the early luteal/midluteal phase than in the early follicular phase (0.89 ± 0.37 vs. 0.75 ± 0.27 mL/[min · kg], p = 0.03). HVRe was similar in postmenopausal versus premenopausal women. HCRe was lower in postmenopausal women ( p < 0.001), due to aging. HVRe decreased from second to fourth decade of age and increased from fourth to eighth decade, while HCRe consistently decreased with aging. Oral contraception or hormonal treatment had no effect on responses to hypoxia. The prevalence of sAMS was similar in all groups. Severe high-altitude illness score was higher and HVRe lower in women with sAMS. Conclusion: (i) physiological responses to hypoxic exercise depend on the ovarian cycle phase and menopause status, (ii) oral contraception and hormonal treatment have no influence on the tolerance to high altitude, and (iii) independent of hormonal status, aging modulates physiological responses to hypoxia.
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Richalet et al. (2019) conducted an observational in Hypoxia / High altitude exposure (n=1,060). Hormonal status (menstrual cycle phase, oral contraception, menopause) vs. Different hormonal states was evaluated on Hypoxic ventilatory response at exercise (HVRe) (p=0.03). In premenopausal women without contraception, hypoxic ventilatory response at exercise was higher in the early luteal/midluteal phase than in the early follicular phase (0.89 vs 0.75 mL/[min·kg]; p=0.03).
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