Sleep restriction to 5 hours significantly increased heart rate and decreased heart rate variability compared to baseline, whereas sleep fragmentation did not significantly affect cardiac autonomic parameters.
RCT (n=20)
Open-label
Randomized cross-over
No
Does sleep fragmentation or partial sleep restriction affect heart rate variability and cardiac autonomic tone during the night in male subjects?
Partial sleep restriction, but not sleep fragmentation, increases sympathetic tone and decreases vagal tone during the night, leading to increased autonomic stress.
Effect estimate: r = 0.30
Absolute Event Rate: 56.39% vs 54.52%
p-value: p=0.018
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.
Schlagintweit et al. (Mon,) conducted a rct in Healthy (n=20). Sleep restriction and sleep fragmentation vs. Undisturbed baseline night (8 hours of sleep) was evaluated on Heart rate during sleep stage N1 (sleep restriction vs baseline) (r = 0.30, p=0.018). Sleep restriction to 5 hours significantly increased heart rate and decreased heart rate variability compared to baseline, whereas sleep fragmentation did not significantly affect cardiac autonomic parameters.