Cardiac autonomic functions in obese children

Objective: the autonomic nervous system is assumed to have a role in the pathophysiology of obesity. in this study,we evaluated the autonomic system by measuring heart rate variability (hrv) in obese children. methods: thirty-two obese and 30 healthy children (mean ages: 11.6±2.0 years and 11.0±2.9 years,respectively) were enrolled in the study. obesity was defined as a body mass index higher than 97 th percentile for age- and gender-specific reference values. all participants were free of any disease and none of them was receiving any medication. twenty-four-hour ambulatory electrocardiographic recordings were obtained and the time-domain and frequency-domain indices of hrv were analyzed. the study group was evaluated with respect to insulin resistance by homa-ir values. results: a significant decrease in calculated hrv variables was observed in obese children as compared to controls. the hrv alteration was found in both time-domain and frequency-domain parameters. the subgroup analysis of the study group revealed a significant decrease in all investigated hrv parameters in the insulin-resistant obese children compared to the non-insulin-resistant obese ones. conclusions: our results indicate that hrv is decreased in obese children,which implies parasympathetic withdrawal and sympathetic predominance. a marked decrease in hrv was observed in insulin-resistant obese children compared to their non-insulin-resistant counterparts. we propose that autonomic imbalance pertaining especially to insulin resistance may be involved in the pathogenesis of obesity in pediatric patients. © journal of clinical research in pediatric endocrinology,published by galenos publishing.