A1 Refereed original research article in a scientific journal
Sleep stage dependent patterns of nonlinear heart rate dynamics in postmenopausal women
Authors: Virtanen I, Eeva EC, Polo-Kantola P, Huikuri H
Publisher: ELSEVIER
Publication year: 2007
Journal: Autonomic Neuroscience: Basic and Clinical
Journal name in source: AUTONOMIC NEUROSCIENCE-BASIC & CLINICAL
Journal acronym: AUTON NEUROSCI-BASIC
Volume: 134
First page : 74
Last page: 80
Number of pages: 7
ISSN: 1566-0702
DOI: https://doi.org/10.1016/j.autneu.2007.01.010
Abstract
Objective: To study the effects of sleep stage changes on nocturnal nonlinear heart rate variability (HRV) in postmenopausal women.Design: A prospective study.Population: Seventy-one healthy postmenopausal women.Methods: The women underwent two separate sleep studies four months apart. One steady state epoch per night of the awake state, stage 2 (light) non-REM sleep, stage 3-4 (deep) non-REM sleep and REM sleep were extracted. From the ECG, the fractal scaling exponents alpha(1), and alpha(2), approximate entropy (ApEn), the Poincare plot variability coefficients SDI and SD2, along with the low (LF) and high frequency (HF) bands of linear HRV as well as the LF/HF ratio were calculated.Results: None of the spectral measures of HRV changed significantly during the non-REM sleep compared to awake state. However, in non-REM sleep, alpha(2) (p<0.001) decreased significantly compared to the awake state, while g, and ApEn remained unchanged. SDI was slightly increased in stage 2 sleep (p<0.05), while SD2 decreased in slow wave sleep (p<0.001). In REM sleep, a, values returned to the awake values, while ApEn and alpha(1) increased above the awake levels (p<0.01 for all variables), and SDI decreased (p<0.01). HF spectral component decreased slightly (p<0.05 compared to stage 2 sleep) and LF/HF ratio increased during REM sleep (p < 0.00 1). ApEn and a, had no correlations with any of the spectral measures of HRV, and a 1 had a modest correlation with the LF/HF ratio only during sleep.Conclusions: We found that nonlinear indices of HRV describe specific features in HR dynamics during various sleep stages that are not detected by traditional spectral HRV indices. (C) 2007 Elsevier B.V. All rights reserved.
Objective: To study the effects of sleep stage changes on nocturnal nonlinear heart rate variability (HRV) in postmenopausal women.Design: A prospective study.Population: Seventy-one healthy postmenopausal women.Methods: The women underwent two separate sleep studies four months apart. One steady state epoch per night of the awake state, stage 2 (light) non-REM sleep, stage 3-4 (deep) non-REM sleep and REM sleep were extracted. From the ECG, the fractal scaling exponents alpha(1), and alpha(2), approximate entropy (ApEn), the Poincare plot variability coefficients SDI and SD2, along with the low (LF) and high frequency (HF) bands of linear HRV as well as the LF/HF ratio were calculated.Results: None of the spectral measures of HRV changed significantly during the non-REM sleep compared to awake state. However, in non-REM sleep, alpha(2) (p<0.001) decreased significantly compared to the awake state, while g, and ApEn remained unchanged. SDI was slightly increased in stage 2 sleep (p<0.05), while SD2 decreased in slow wave sleep (p<0.001). In REM sleep, a, values returned to the awake values, while ApEn and alpha(1) increased above the awake levels (p<0.01 for all variables), and SDI decreased (p<0.01). HF spectral component decreased slightly (p<0.05 compared to stage 2 sleep) and LF/HF ratio increased during REM sleep (p < 0.00 1). ApEn and a, had no correlations with any of the spectral measures of HRV, and a 1 had a modest correlation with the LF/HF ratio only during sleep.Conclusions: We found that nonlinear indices of HRV describe specific features in HR dynamics during various sleep stages that are not detected by traditional spectral HRV indices. (C) 2007 Elsevier B.V. All rights reserved.
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