Ventilatory response to hypoxia and tolerance to high altitude in women: Influence of menstrual cycle, oral contraception and menopause

Abstract

Tolerance to high altitude in women might be influenced by hormonal status since female hormones are known to modulate ventilation. We explored the influence of 1) the phase of menstrual cycle, 2) oral contraception, 3) menopause with or without hormonal treatment, on ventilatory (HVRe) and cardiac (HCRe) responses to hypoxia at exercise in 1060 women prior to exposure at high altitude. HCRe and HVRe were measured during a routine hypoxia exercise test. Prevalence of Severe High Altitude Illness (SHAI) was assessed in a subgroup of 260 women. Four groups of women were defined: non‐menopaused with or without oral contraception; menopaused with or without hormonal treatment. In non‐menopaused women without contraception, HVRe was higher in the early luteal phase than in the early follicular phase (0.89±0.37 vs 0.75±0.27 ml/min/kg, p=0.03). HVRe was higher (p=0.016) and HCRe lower (p<0.001) in menopaused vs non‐menopaused women. Independently of hormonal status, HVRe decreased from second to fourth decade of age and increased from fourth to eighthdecade, while HCRe consistently decreased with ageing. Oral contraception or hormonal treatment had no effect on responses to hypoxia. The prevalence of SHAI was similar in all groups. SHAI prediction score was higher and HVRe lower in women with SHAI, without taking actetazolamide. In conclusion, 1) physiological responses to hypoxia depends on the ovarian cycle phase and on menopause status, 2) oral contraception, and hormonal treatment have no influence on response to hypoxia and tolerance to high altitude, 3) independently of hormonal status, ageing modulates physiological responses to hypoxia, 4) the optimal phase for high altitude acclimatization for women would be the early luteal phase.Support or Funding InformationAssociation pour la Recherche en Physiologie de l'EnvironnementThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.