Heart rate variability during sleep in healthy term newborns in the early postnatal period

Area of Science:

• Neonatal physiology
• Cardiovascular regulation
• Sleep science

Background:

• Heart rate variability (HRV) is a key indicator of autonomic nervous system function.
• Understanding normative HRV in newborns is crucial for identifying deviations associated with illness.
• Sleep state significantly influences physiological parameters in infants.

Purpose of the Study:

• To establish normative time- and frequency-domain heart rate variability (HRV) measures in healthy newborns within the first 12 hours of life.
• To investigate the influence of sleep state (quiet sleep vs. active sleep) on HRV parameters.
• To provide a reference table of HRV metrics for potential clinical application in neonatal care.

Main Methods:

• Collected multi-channel video electroencephalogram (EEG) to classify sleep states (quiet sleep/QS and active sleep/AS) in 30 healthy newborns (<12 h old).
• Extracted heart rate (HR) spectral components: very low frequency (VLF), low frequency (LF), and high frequency (HF).
• Calculated and averaged time- and frequency-domain HRV metrics across all patients and per sleep state to generate normative values.

Main Results:

• A significant peak in the respiratory sinus arrhythmia (RSA) band was observed in 80% of infants during quiet sleep (QS), but in 0% during active sleep (AS).
• The majority of HRV metrics demonstrated statistically significant differences between QS and AS.
• Normative HRV values were averaged and tabulated for both sleep states.

Conclusions:

• Respiratory sinus arrhythmia (RSA) activity is present during quiet sleep in healthy newborns within the first 12 hours of life.
• HRV measures are demonstrably affected by the infant's sleep state.
• The reported averaged HRV metrics serve as a valuable reference for interpreting HRV data in ill newborns.