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Heart rate variations during sleep in preadolescents
Insights
This study provides normative heart rate variability data for 8-10 year old males during sleep. Preadolescent sleep patterns show unique cardiac autonomic control, differing from adults.
Area of Science:
- Cardiology
- Pediatric Sleep Medicine
- Autonomic Nervous System Function
Background:
- Heart rate variations during sleep are well-documented in infants and adults, but normative data for children and adolescents are lacking.
- Understanding these variations is crucial for assessing cardiovascular health in developing populations.
Purpose of the Study:
- To establish normative data for heart rate variations during sleep in preadolescent males (8-10 years old).
- To describe sleep-related heart rate variability using time-domain and nonlinear methods.
- To compare preadolescent sleep cardiac patterns with existing adult data.
Main Methods:
- Utilized time-domain measures and Poincare plots to analyze beat-to-beat (RR) intervals during two nights of undisturbed sleep.
- Analyzed 14 healthy males aged 8-10 years.
- Related heart rate variables to specific sleep stages (REM, SW, stage 2) and sleep cycles.
Main Results:
- Mean heart rate tended to be higher in rapid eye movement (REM) sleep versus slow-wave (SW) and stage 2 sleep, though not significantly.
- Heart rate variability was highest in stage 2 and lowest in SW sleep, with no significant variation across sleep stages.
- Significant trends observed across sleep cycles included a decrease in mean heart rate and an increase in heart rate variability.
- Poincare plots showed significant individual differences but remarkable night-to-night consistency in patterns.
- Sleep-stage plots indicated reduced variability in SW sleep compared to REM and stage 2 sleep.
Conclusions:
- Preadolescent sleep-related heart rate variations exhibit distinct characteristics compared to adults.
- These differences are likely due to developmental changes in autonomic cardiac control, specifically increased parasympathetic influence.
- The findings provide essential normative data for pediatric sleep and cardiovascular research.
Abstract:
Heart rate variations during sleep have been documented for infant and adult populations, but not for children and adolescents. To provide normative data for the preadolescent age group, this investigation used a combination of time-domain measures and nonlinear procedures (Poincare plots) to describe heart rate variations during two consecutive nights of undisturbed baseline sleep in 14 normal 8- to 10-year-old males. Heart rate variables, based on all-night analyses of computer-determined beat-to-beat (RR) intervals, were related to sleep stage and sleep cycle measures within and across nights. Time-domain summary statistics revealed a tendency for higher mean heart rates in rapid eye movement (REM) compared to slow-wave (SW) and stage 2 sleep, but the differences were not significant. Heart rate variability, as measured by average RR interval standard deviation, was greatest in stage 2 and least in SW sleep, but it did not vary significantly across sleep stages. Analyses of heart rate variables across the initial four sleep cycles showed a significant heart rate decrease (quadratic trend) and a significant increase (linear trend) for heart rate variability. All effects replicated across nights. Poincare plots revealed wide-ranging individual differences, generally characterized by greater dispersion at longer RR intervals and a remarkable night-to-night consistency in whole-night as well as stage-specific patterns. The sleep-stage plots uniformly indicated reduced overall range and variability in SW relative to REM and stage 2 and a general equivalence of stage 2 and REM patterns. The results indicate several features of sleep-related heart rate variations in preadolescents that differ from those in adults. The differences can be attributed to developmental variations in autonomic cardiac control and are consistent with increased parasympathetic influences reported to occur at this time.