Effects of sleep fragmentation and partial sleep restriction on heart rate variability during night.

Julia Schlagintweit, Naima Laharnar, Martin Glos, Maria Zemann, Artem V Demin, Katharina Lederer, Thomas Penzel, Ingo Fietze

Journal: Scientific reports 2023;13(1):6202

PMID: 37069226

Free Full Text on Nature Publishing Group View on PubMed

Plain Language Summary

Adequate sleep is essential for physical and mental health and wellbeing. This randomised cross-over study of 20 healthy men compared the effects of sleep restriction (sleeping 5 instead of 8 hours) and sleep fragmentation (being woken hourly during the 8-hour sleeping time) on heart rate (HR) and heart rate variability (HRV), both markers of the sympathetic (“fight or flight”) and parasympathetic (“rest and digest”) arms of the autonomic nervous system. Sleep restriction increased HR and decreased HRV, suggesting increased sympathetic and decreased parasympathetic activation. This affected the lighter sleep phases in particular. Sleep fragmentation, on the other hand, did not affect HR or HRV compared to baseline. The authors conclude that sleep restriction may cause more stress than sleep fragmentation.

Abstract

We developed a cross-over study design with two interventions in randomized order to compare the effects of sleep fragmentation and partial sleep restriction on cardiac autonomic tone. Twenty male subjects (40.6 ± 7.5 years old) underwent overnight polysomnography during 2 weeks, each week containing one undisturbed baseline night, one intervention night (either sleep restriction with 5 h of sleep or sleep fragmentation with awakening every hour) and two undisturbed recovery nights. Parameters of heart rate variability (HRV) were used to assess cardiac autonomic modulation during the nights. Sleep restriction showed significant higher heart rate (p = 0.018) and lower HRV-pNN50 (p = 0.012) during sleep stage N1 and lower HRV-SDNN (p = 0.009) during wakefulness compared to the respective baseline. For HR and SDNN there were recovery effects. There was no significant difference comparing fragmentation night and its baseline. Comparing both intervention nights, sleep restriction had lower HRV high frequency (HF) components in stage N1 (p = 0.018) and stage N2 (p = 0.012), lower HRV low frequency (LF) (p = 0.007) regarding the entire night and lower SDNN (p = 0.033) during WASO during sleep. Sleep restriction increases sympathetic tone and decreases vagal tone during night causing increased autonomic stress, while fragmented sleep does not affect cardiac autonomic parameters in our sample.

Address: Interdisciplinary Center of Sleep Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany. [email protected].; Interdisciplinary Center of Sleep Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany.; Advanced Sleep Research GmbH, Luisenstraße 54-55, 10117, Berlin, Germany.; Institute of Biomedical Problems, Russian Academy of Science, 76a, Khoroshevskoe Shosse, Moscow, Russia, 123007.; The Fourth People's Hospital of Guangyuan, Guangyuan, China.

DOI: 10.1038/s41598-023-33013-5