Among children with abdominal pain-related disorders of gut-brain interaction, heart rate variability was associated with sleep disturbances in a sex-specific manner, with lower low-frequency HRV associated with greater sleep-disordered breathing in both sexes.
Key Findings
Results
Higher parasympathetic HRV activity was associated with longer sleep onset delay in girls with AP-DGBI.
The association was found specifically in girls, not boys, indicating sex-specific autonomic-sleep relationships.
Measures of parasympathetic activity used were Ln RMSSD and Ln pNN50.
HRV was measured after dinner using a Polar monitor.
Sample consisted of 156 children ages 7-12 years with AP-DGBI from a randomized control trial.
Associations were determined using partial correlations controlling for age and stratified by sex.
Results
Lower heart rate was correlated with increased sleep anxiety in girls with AP-DGBI.
This association was observed only among girls in the sex-stratified analysis.
Sleep disturbances were evaluated using the Children's Sleep Habits Questionnaire.
The finding suggests a parasympathetic or autonomic tone component related to anxiety around sleep in girls.
Partial correlations controlled for age.
Results
Lower autonomic balance (Ln LF/HF ratio) was associated with increased daytime sleepiness in boys with AP-DGBI.
This association was found only among boys, not girls, highlighting sex differences in autonomic-sleep relationships.
The LF/HF ratio is used as an index of autonomic balance between sympathetic and parasympathetic activity.
Sleep characteristics were assessed with the Children's Sleep Habits Questionnaire.
Analysis was stratified by sex and controlled for age.
Results
Lower low-frequency HRV was associated with greater sleep-disordered breathing in both girls and boys with AP-DGBI.
This was the only HRV-sleep association observed in both sexes rather than being sex-specific.
Post hoc analysis of multiple HRV indices revealed that children with sleep-disordered breathing had significantly lower HRV compared to those without disordered breathing.
Low-frequency HRV reflects both sympathetic and parasympathetic modulation.
Sleep-disordered breathing was assessed via the Children's Sleep Habits Questionnaire.
Results
Children with sleep-disordered breathing had significantly lower overall HRV compared to those without sleep-disordered breathing.
This was identified through a post hoc analysis examining multiple HRV indices.
The finding applied to both boys and girls.
The study population was children ages 7-12 years with AP-DGBI (n=156).
This finding supports the role of autonomic nervous system dysfunction in sleep-disordered breathing in this pediatric population.
Methods
The study used baseline data from a randomized controlled trial of 156 children ages 7-12 years diagnosed with AP-DGBI.
HRV was measured after dinner using a Polar monitor.
Sleep disturbances were evaluated using the Children's Sleep Habits Questionnaire.
Associations between HRV indices and sleep characteristics were determined using partial correlations controlling for age.
Analyses were stratified by sex to detect potential sex differences in autonomic-sleep associations.
Discussion
The autonomic nervous system was identified as a potential underlying physiological mechanism linking AP-DGBI and sleep disturbances in children.
HRV is described as a non-invasive measure of autonomic nervous system activity.
The sex-stratified findings suggest that autonomic influences on sleep may differ between girls and boys.
The authors call for future longitudinal studies to confirm this relationship.
This study specifically aimed to elucidate physiological mechanisms of disturbed sleep in children with AP-DGBI.
What This Means
This research suggests that the autonomic nervous system — the part of the nervous system that controls automatic body functions like heart rate — may play a role in sleep problems experienced by children who have chronic abdominal pain conditions (called abdominal pain-related disorders of gut-brain interaction, or AP-DGBI). The researchers measured heart rate variability (HRV), a way of assessing how well the autonomic nervous system is functioning, in 156 children aged 7 to 12, and compared it to their sleep habits as reported on a standardized questionnaire. They found that different aspects of autonomic activity were linked to different sleep problems, and that these relationships differed between girls and boys.
Among girls, higher parasympathetic (rest-and-digest) nervous system activity was linked to taking longer to fall asleep, and lower heart rate was associated with more anxiety around sleep. Among boys, a lower balance between the two branches of the autonomic nervous system was associated with more daytime sleepiness. In both boys and girls, lower low-frequency HRV — a marker of overall autonomic regulation — was associated with more sleep-disordered breathing (such as snoring or breathing difficulties during sleep). A follow-up analysis confirmed that children with sleep-disordered breathing had significantly lower HRV overall compared to those without it.
This research suggests that the way the autonomic nervous system functions may help explain why children with chronic abdominal pain so often have trouble sleeping, and that these mechanisms may work differently in girls versus boys. The authors note that future studies following children over time are needed to better understand whether autonomic dysfunction causes sleep problems, or vice versa, in this group of children.
Kamp K, Burr R, Matherne C, Simonds E, Murphy T, Heitkemper M, et al.. (2026). Relationship Between Heart Rate Variability and Sleep Among Girls and Boys With Abdominal Pain-Related Disorders of Gut-Brain Interaction.. Neurogastroenterology and motility. https://doi.org/10.1111/nmo.70293