Analysis of spectral indexes for heart rate variability in middle-aged men and postmenopausal women

Author(s)

VFC Neves ^[1] ; NM Perpétuo ^[2] ; DI Sakabe ^[3] ; AM Catai ^[4] ; L Gallo Jr ^[5] ; MF Silva de Sá ^[6] ; LEB Martins ^[7] ; E Silva

Affiliation

^[1] Universidade Federal de São Carlos. Departamento de Fisioterapia. Núcleo de Pesquisa em Exercício Físico - Brasil

^[2] Universidade Federal de São Carlos. Departamento de Fisioterapia. Núcleo de Pesquisa em Exercício Físico - Brasil

^[3] Universidade de São Paulo. Hospital das Clínicas. Faculdade de Medicina de Ribeirão Preto - Brasil

^[4] Universidade Federal de São Carlos. Departamento de Fisioterapia. Núcleo de Pesquisa em Exercício Físico - Brasil

^[5] Universidade de São Paulo. Hospital das Clínicas. Faculdade de Medicina de Ribeirão Preto - Brasil

^[6] Universidade de São Paulo. Hospital das Clínicas. Faculdade de Medicina de Ribeirão Preto - Brasil

^[7] Universidade Estadual de Campinas. Faculdade de Educação Física - Brasil

• Document type: Journal article
• Source: BRAZILIAN JOURNAL OF PHYSICAL THERAPY; v. 10, n. 4, p. 401-406, 2006-12-00.

Abstract

OBJECTIVE: To analyze and compare heart rate variability (HRV) in middle-aged men and women under resting conditions. METHOD: Ten men (54 ± 3.2 years) and fourteen postmenopausal women (56 ± 2.6 years) who were not using hormonal therapy were studied. Heart rates (HR) and R-R intervals (iR-R) on a beat-to-beat basis were obtained from electrocardiograms over an eight-minute period under resting conditions, in the supine and sitting positions. The HRV was analyzed in the frequency domain by means of fast Fourier transforms and the low (LF) and high (HF) frequency bands were obtained and presented as normalized units (LFnu and HFnu) and the LF/HF ratio. Wilcoxon and Mann-Whitney non-parametric statistical tests were used, with the significance level set at 5%. RESULTS: Comparing between the groups, the women presented significantly higher HFnu and lower LFnu and LF/HF ratios than did the men (p<0.05). Comparing within the groups, no significant differences (p>0.05) were found in the HRV indexes between the supine and sitting positions for either study group. CONCLUSION: Our results show greater vagal modulation and lower sympathetic activity in autonomic heart rate control among women than among men of similar age. This suggests that the gender-related autonomic differences are not solely dependent on estrogen levels, since the women studied were already postmenopausal. Other factors may be contributing towards these differences. (AU)