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Type: Journal article
Title: The inconsistent nature of heart rate variability during sleep in normal children and adolescents
Author: Kontos, A.
Baumert, M.
Lushington, K.
Kennedy, J.
Kohler, M.
Cicua-Navarro, D.
Pamula, Y.
Martin, J.
Citation: Frontiers in Cardiovascular Medicine, 2020; 7(9):19-1-19-11
Publisher: Frontiers Media
Issue Date: 2020
ISSN: 2297-055X
Statement of
Anna Kontos, Mathias Baumert, Kurt Lushington, Declan Kennedy, Mark Kohler, Diana Cicua-Navarro, Yvonne Pamula, and James Martin
Abstract: Introduction: Cardiac function is modulated by multiple factors including exogenous (circadian rhythm) and endogenous (ultradian 90-110 min sleep cycle) factors. By evaluating heart rate variability (HRV) during sleep, we will better understand their influence on cardiac activity. The aim of this study was to evaluate HRV in the dark phase of the circadian rhythm during sleep in healthy children and adolescents. Methods: One 3 min segment of pre-sleep electrocardiography (EEG) and 3, 6 min segments of electrocardiography recorded during polysomnography from 75 healthy children and adolescents were sampled during progressive cycles of slow wave sleep (SWS1, SWS2, SWS3). Three, 3 min segments of rapid eye movement sleep (REM) were also assessed, with REM1 marked at the last REM period before awakening. Studies that recorded REM3 prior to SWS3 were used for assessment. HRV variables include the following time domain values: mean NN (average RR intervals over given time), SDNN (Standard Deviation of RR intervals), and RMSSD (root Mean Square of beat-to-beat Differences). Frequency domain values include: low frequency (LF), high frequency (HF), and LF:HF. Results: Mixed linear effects model analysis revealed a significant difference in time and frequency domain values between sleep cycles and stages. Mean NN was lowest (highest heart rate) during pre-sleep then significantly increased across SWS1-3. Mean NN in SWS1 was similar to all REM periods which was significantly lower than both SWS2 and SWS3. SDNN remained at pre-sleep levels until SWS3, and then significantly increased in REM1&2. There was a large drop in LF from pre-sleep to SWS1. As cycles progressed through the night, LF remains lower than awake but increases to awake like levels by REM2. RMSSD and HF were lowest in pre-sleep and increased significantly by SWS1 and remain high and stable across stages and cycles except during the REM3 period where RMSSD decreased. Conclusion: Our results demonstrate that there are considerable changes in the spectral analysis of cardiac function occurring during different sleep stages and between sleep cycles across the night. Hence, time of night and sleep stage need to be considered when reporting any HRV differences.
Keywords: Heart rate variability; children; sleep; circadian rhythm; ultradium rhythm
Rights: Copyright © 2020 Kontos, Baumert, Lushington, Kennedy, Kohler, Cicua-Navarro, Pamula and Martin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
RMID: 1000017595
DOI: 10.3389/fcvm.2020.00019
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Appears in Collections:Medicine publications

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