In healthy adults, changes in sleep regularity over 12 weeks were significantly correlated with changes in heart rate variability, including high-frequency power (r=-0.79; p<0.01).
Observational (n=12)
Does maintaining a consistent sleep onset improve heart rate variability in healthy adults with irregular sleep patterns?
Improving sleep regularity in healthy adults is associated with favorable changes in heart rate variability, suggesting a potential lifestyle intervention to improve autonomic balance.
Effect estimate: r=-0.79 for HF
p-value: p=<0.01
Abstract Introduction Sleep regularity has been shown to be a stronger predictor of mortality compared to sleep duration, though the underlying mechanisms are incompletely understood. Heart rate variability (HRV), a measure of cardiac autonomic modulation, is associated with cardiovascular morbidity and mortality. While HRV is traditionally analyzed using linear methods (e.g., frequency-domain analyses), there is growing interest in nonlinear measures to assess the dynamic complexity of cardiac regulation. However, the influence of sleep regularity on both linear and nonlinear HRV is unclear. We therefore assessed the association between sleep regularity and HRV in healthy adults. Methods HRV was obtained in 12 participants (6 female) via electrocardiography during 10-min supine rest and assessed using linear (high frequency HF; low frequency LF/HF ratio) and nonlinear (detrended fluctuation analysis DFA-α1 and -α2) indices. Sleep regularity was quantified using the standard deviation (SD) of diary-determined sleep onset across ~14 days. Participants were classified as regular (SD 1h; n=5) or irregular sleepers (SD=1h; n=7). Irregular sleepers were instructed to maintain a consistent sleep onset (±30min) for 12-weeks. Differences between groups were assessed using independent t-tests and relationships between SD sleep onset and HRV were assessed using Pearson correlation analyses. Results There were no differences between groups in age (mean±SD, irregular vs. regular, respectively; 30.7±7.8 vs. 27.2±8.5y; p=0.23), sleep onset timing (24:38±1:45 vs. 23:37±1:14; p=0.14), or DFA-α2 (0.27±0.11 vs. 0.36±0.20; p=0.16). At baseline, irregular sleepers had higher SD sleep onset (1.4±0.4 vs. 0.8±0.2h; p 0.01), LF/HF ratio (2.4±1.8 vs. 0.6±0.5%; p=0.03), DFA-α1 (1.10±0.22 vs. 0.81±0.20; p=0.02), and lower HF (37.1±20.5 vs. 63.1±7.1nu; p=0.02). In the entire sample, SD sleep onset was inversely correlated with HF (r=-0.63; p=0.02) and positively correlated with LF/HF ratio (r=0.75; p 0.01) and DFA-α1(r=0.61; p=0.03) at baseline. At 12-weeks, the change in SD sleep onset was inversely correlated with change in HF (r=-0.79; p 0.01) and positively correlated with change in LF/HF ratio (r=0.77; p 0.01) and DFA-α1(r=0.66; p=0.01). Conclusion Irregular sleep patterns are associated with altered cardiac regulatory dynamics and may be one mechanism contributing to adverse outcomes. Improving sleep regularity may be a potential interventional target to improve the autonomic balance and cardiovascular adaptation. Support (if any)
Shafer et al. (2026) conducted an observational in Healthy adults (n=12). Maintaining a consistent sleep onset (±30min) vs. Regular sleepers (baseline comparison) was evaluated on Heart rate variability (linear and nonlinear indices) (r=-0.79 for HF, p=<0.01). In healthy adults, changes in sleep regularity over 12 weeks were significantly correlated with changes in heart rate variability, including high-frequency power (r=-0.79; p<0.01).