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Gender Affects Sympathetic and Hemodynamic Responses to Posture Changes and Hypoxia
Author(s) -
Chen LaingYu,
Wang Jongshyan
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1286-b
Subject(s) - hypoxia (environmental) , medicine , heart rate variability , basal (medicine) , heart rate , orthostatic vital signs , baroreceptor , blood pressure , endocrinology , cardiology , physiology , oxygen , chemistry , organic chemistry , insulin
Background and Purpose: Susceptibility for orthostatic intolerance and acute mountain sickness are more common in women than in men. However, few studies were to investigate regarding role of gender on heart rate variability (HRV) changed by baroreceptor and chemoreceptor stimulation. Therefore, this study evaluated whether gender difference affected the HRV values in response to posture change and hypoxic condition. Methods and Results: We studied 40 healthy volunteers (male: n=20, age=19.9±0.9; female: n=20, age=20.2±0.7) who were subjected to posture change (i.e., tilted up 35°) and hypoxia intervention (i.e. exposure to 12% O 2 for 1 hour). HRV, blood pressure (BP) and arterial oxygen saturation were determined at the experimental period. Our results showed that females had lower basal low frequency (LF) power and basal LF/high frequency (HF) ratio (LF/HF ratio) than males (520±56 ms 2 and 1027±175 ms 2 ; 0.51±0.05 and 1.49±0.21, respectively; p <0.05); intervention of 12% O 2 raised the HF/LF ratio in females by either increasing the LF power or decreasing the HF power, as well as in males by increasing the LF power; and when subjects were tilted up 35°, females displayed smaller the HF/LF ratio and lower BP level than males.Conclusion: We conclude that the HRV changes induced by posture change and hypoxia may be associated with sex difference, suggesting physical‐ and chemical‐mediated autonomic nerve systems have distinct regulatory mechanisms between men and women.