Cardiac Autonomic Function at Baseline and under Stress and Its Relationship to Circulatory Markers of Inflammation in Obese Compared to Nonobese Children: A Pilot Study

Abstract

Background/Aims: The autonomic nervous system (ANS) provides neurogenic control of inflammatory reactions. ANS changes in obesity may result in inflammation. This study sought to gain insight into cardiac autonomic dysfunction and inflammation in childhood obesity, and to gather pilot data on the potential relationship between altered ANS and inflammation. Methods: Fifteen obese children and adolescents without metabolic complications and 15 nonobese controls underwent heart rate variability and impedance cardiography testing during rest, mental stress, and physical stress. Inflammatory cytokines and immune reactivity were measured. Results: There was no statistically significant difference between groups in cardiac ANS testing at rest or in response to stress. Median high-sensitivity C-reactive protein (hsCRP) was higher in the obese group [obese 2.6 mg/l (IQR 1.6-11.9); nonobese 0.3 mg/l (IQR 0.2-0.7); p < 0.001]. Interleukin-6 and tumour necrosis factor-α were similar between groups. Immune reactivity testing (in vitro Toll-like receptor stimulation) revealed a strong, but comparable, inflammatory response in both groups. Conclusions: Obese children and adolescents without metabolic complications did not have cardiac ANS dysfunction. While hsCRP was elevated, systemic cytokines were not raised. Compared to prior studies, which often focused on children with obesity and its complications, it is encouraging that obese children without metabolic complications may not yet have autonomic dysfunction.

Synergistic effect of energy drinks and overweight/obesity on cardiac autonomic testing using the Valsalva maneuver in university students

“…Contrary to our observations, Hursh et al found no significant difference in cardiac autonomic testing between normal and obese subjects, although they discovered high levels of C-reactive protein, an inflammatory marker in obese subjects, suggesting a possible link between development of metabolic syndrome and cardiovascular diseases. 34 Autonomic disturbance was correlated in our study with obesity that originated from increased sympathetic and decreased parasympathetic activity as witnessed by augmented systolic blood pressure, diastolic blood pressure and mean arterial blood pressure in the OW/OB subjects. Autonomic imbalance may alter hemodynamics by affecting peripheral vascular resistance, adrenal medullary activity, sinoatrial nodal discharge and myocardial contractility.…”

“…Our results are comparable to results witnessed by other researchers. 32 – 34 Al Sunni et al found autonomic imbalances in OW/OB subjects as compared to normal weight subjects using QTc and heart rate variability for autonomic testing. 30 Prior et al found a dose-dependent increase in sympathetic excitation and arterial pressure in response to leptin that was more pronounced in OW/OB subjects.…”

Influence of Acute Physical Activity on Stress Reactivity in Obese and Normal Weight Children: A Randomized Controlled Trial

“…Regarding the ANS system, higher BP reactivity to laboratory stress was associated with a greater abdominal waist and waist-to-hip ratio in adolescents [21, 22] and a greater HR reactivity with percentage body fat following an interpersonal stressor in pre-pubertal children [23]. However, recent studies did not reveal any ANS dysfunction in obese children and adolescents in response to acute stressors [24, 25]. Both heightened and blunted cortisol and cardiovascular stress reactivity can be considered maladaptive, depending on the health outcome [26, 27].…”