Cardiac autonomic regulation in response to a mixed meal is impaired in obese children and adolescents: The role played by insulin resistance

Context: Obesity in children/adolescents has been associated with subtle cardiac abnormalities, including myocardial dysfunction and cardiac autonomic dysregulation at rest, both likely responsible for a higher mortality in adulthood. Food intake induces remarkable adjustments of cardiovascular autonomic activity in healthy subjects. Copyright

Objective: The objective of the study was to evaluate in obese children/adolescents meal-induced cardiac autonomic response and the role played by insulin resistance.

Design and Setting: Sixty-eight obese and 30 matched normal-weight children/adolescents underwent blood sampling and cardiovascular autonomic analysis while recumbent and 20 minutes after a mixed meal ingestion. Spectrum analysis of the R-R interval and systolic blood pressure (SBP) variability provided the indices of sympathetic [low frequency (LFRR)] and vagal [high frequency (HFRR)] modulation of the sinoatrial node and the low frequency component of SBP. The homeostasis model assessment of insulin resistance served to separate insulin resistant (n = 35) from non insulin resistant (n = 33) obese children/adolescents.

Results: At baseline, C-reactive protein, the LFRR to HFRR ratio, SBP, and low frequency oscillatory component of SBP variability in obese children/adolescents were significantly (P

Conclusions: Autonomic modulation of the heart was impaired after eating in obese children/ adolescents. This abnormality was exaggerated among insulin resistant subjects and strongly correlated with the degree of insulin resistance.