Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Sachse, C.
Gender differences in cardiovascular responses to orthostatic challenge in healthy older persons
Humanmedizin; [ Diplomarbeit ] Graz Medical University; 2017. pp. 72
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Goswami Nandu
- Altmetrics:
- Abstract:
- Introduction: Premenopausal women show a higher incidence of orthostatic hypotension than age-matched men, but there is limited data available on gender differences in cardiovascular responses to orthostatic challenge in healthy older persons. Studying orthostatic hypotension is important because it is a major contributing factor of falls among older persons and it is associated with higher morbidity and mortality at an older age. Aims: The overall aim of this study was to investigate gender differences in hemodynamic and autonomic responses to orthostatic challenge in healthy older males and females. Due to the effects of menopause on sex-steroid hormones, it was hypothesized that an orthostatic challenge in older persons will not lead to differences in cardiovascular and autonomic responses across gender. Methodology: Fourteen older healthy women and ten age-matched men performed a sit to stand test (five minutes of sitting followed by six minutes of standing). Task Force® Monitor was used to continuously measure the following beat-to-beat hemodynamic parameters: heart rate, systolic blood pressure, diastolic blood pressure, mean blood pressure, stroke index, cardiac index and total peripheral resistance index. Cardiac autonomic activity was calculated using power spectral analysis of heart rate variability. Measurement of low-frequency (LF: 0.04 to 0.15 Hz) and high-frequency (HF: 0.15 to 0.4 Hz) components was made in absolute values and normalized units. Results: More women than men fulfilled the criteria for orthostatic hypotension (35.7% vs. 11.1%). However, across all hemodynamic parameters, there were no significant differences between the sexes at baseline level and during standing. LFnuRRI (median: 70.2 vs. 52.3, p<0.05) and LF/HF ratio (median: 2.4 vs. 1.1, p<0.05) were significantly higher, while HFnuRRI (median 29.8 vs. 47.7, p<0.05) was lower among women during the baseline. All other heart rate variability measures did not differ between both sexes. Conclusion: The data indicate that orthostatic hypotension occurs more frequently in older women than in men. Further study is required to determine the underlying mechanisms contributing to higher incidence of orthostatic hypotension in older females. Additionally, older women showed higher sympathetic and lower parasympathetic activity at rest compared to age-matched men. These results are contradictory to the observations from previous studies, which showed a reduced sympathetic and enhanced parasympathetic activity in women in all ages.