Sympathetic Nerve Function Status in Postmenopausal Women

Abstract

Background: Postmenopausal women usually suffer from increased incidence of cardiovasculardiseases than premenopausal women. Alterations in autonomic nerve functions often develop in thisgroup of women that commonly affect cardiac vagal control and usually associated with sympathetichyperactivity. Objectives: To observe the sympathetic nerve function status in postmenopausalwomen and their relationships with serum estrogen level. Methods: This cross sectional study wascarried 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 ageranged from 45-60 years(group B) and 30 were premenopausal women with age ranged from 20-30years (group A) were enrolled. Premenopausal women were studied during follicular phase of menstrualcycle. Two simple autonomic nerve function tests, rise of diastolic blood pressure (DBP) during handgrip and fall of systolic blood pressure (SBP) on standing were done to assess sympathetic activityand serum estrogen level was measured in both the groups. Data were analysed by unpaired t test andPearson 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 wassignificantly (p<0.001) lower in group B (postmenopause) than those in group A (premenopause). Fallin systolic blood pressure after standing was significantly (p<0.001) higher and rise in diastolic bloodpressure after sustained handgrip was significantly (p<0.001) lower in postmenopausal women thanthose in premenopausal women during their follicular phase of menstrual cycle. Again, rise in diastolicblood 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 statisticallynot significant. In addition, regression analysis further revealed significant association of sympatheticactivity with estrogen level and age in postmenopausal women. Conclusion: From this study it can beconcluded that sympathetic activity is higher in postmenopausal women, which may be related totheir low estrogen level and age as well.Key words: Postmenopause; sympathetic nerve functions; estrogen.DOI: 10.3329/jbsp.v5i1.5417J Bangladesh Soc Physiol. 2010 June; 5(1): 40-45