Sympathetic Nerve Function Status in Postmenopausal Women

Abstract

Background: Postmenopausal women usually suffer from increased incidence of cardiovascular
diseases than premenopausal women. Alterations in autonomic nerve functions often develop in this
group of women that commonly affect cardiac vagal control and usually associated with sympathetic
hyperactivity. Objectives: To observe the sympathetic nerve function status in postmenopausal
women and their relationships with serum estrogen level. Methods: This cross sectional study was
carried out in the Department of Physiology, BSMMU, Dhaka from 1st January to 31st December 2007.
A total number of 60 apparently healthy subjects of whom 30 were postmenopausal women with age
ranged from 45-60 years(group B) and 30 were premenopausal women with age ranged from 20-30
years (group A) were enrolled. Premenopausal women were studied during follicular phase of menstrual
cycle. Two simple autonomic nerve function tests, rise of diastolic blood pressure (DBP) during hand
grip and fall of systolic blood pressure (SBP) on standing were done to assess sympathetic activity
and serum estrogen level was measured in both the groups. Data were analysed by unpaired t test and
Pearson correlation coefficient test. Results: Mean resting SBP and DBP were significantly higher
(p<0.001) in postmenopausal women than premenopausal women. The mean value of estrogen was
significantly (p<0.001) lower in group B (postmenopause) than those in group A (premenopause). Fall
in systolic blood pressure after standing was significantly (p<0.001) higher and rise in diastolic blood
pressure after sustained handgrip was significantly (p<0.001) lower in postmenopausal women than
those in premenopausal women during their follicular phase of menstrual cycle. Again, rise in diastolic
blood pressure after sustained handgrip and fall in systolic blood pressure after standing showed
(p>0.05) negative correlation with estrogen level in the postmenopausal women which was statistically
not significant. In addition, regression analysis further revealed significant association of sympathetic
activity with estrogen level and age in postmenopausal women. Conclusion: From this study it can be
concluded that sympathetic activity is higher in postmenopausal women, which may be related to
their low estrogen level and age as well.

Key words: Postmenopause; sympathetic nerve functions; estrogen.

DOI: 10.3329/jbsp.v5i1.5417

J Bangladesh Soc Physiol. 2010 June; 5(1): 40-45