The 24-h movement behaviours composition is associated with parasympathetic modulation in preschoolers

Area of Science:

• Pediatric physiology
• Autonomic nervous system function
• Behavioral science

Background:

• Heart rate variability (HRV) reflects autonomic nervous system regulation.
• Preschoolers' 24-hour movement behaviors (physical activity, sedentary behavior, sleep) are crucial for development.
• Understanding the interplay between movement behaviors and HRV in young children is important for health.

Purpose of the Study:

• To investigate the associations between 24-hour movement behaviors and heart rate variability (HRV) in preschool children.
• To determine if the composition of physical activity, sedentary behavior, and sleep duration predicts HRV parameters.

Main Methods:

• 123 preschoolers (aged ~4.5 years) wore accelerometers to measure physical activity and sedentary behavior.
• Parent-reported sleep duration was collected.
• Heart rate variability was assessed during a 10-minute resting period.
• Compositional analysis was used to analyze the 24-hour movement patterns.

Main Results:

• The 24-hour movement composition significantly predicted parasympathetic modulation, specifically the Root Mean Square of Successive Differences (RMSSD) (p=0.04, r²=0.13).
• No significant associations were found between the movement composition and other HRV indices like High Frequency (HF) or Low Frequency (LF).
• The findings were adjusted for age, body mass index, and sex.

Conclusions:

• The overall composition of 24-hour movement behaviors in preschoolers is associated with parasympathetic nervous system activity.
• RMSSD, a time-domain index of HRV, appears sensitive to the balance of physical activity, sedentary behavior, and sleep.
• These findings underscore the importance of a holistic approach to children's daily movement for cardiovascular health.