Heart rate variations during sleep in preadolescents

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.