BACKGROUND: Obesity can affect the cardiac autonomic modulation, blood lipid levels and the physical capacity. OBJECTIVE: To study the effect of obesity on the heart rate variability (HRV), blood lipid levels and physical capacity of obese children. METHODS: Thirty children aged 9 to 11 years were studied, divided in two groups: a) 15 obese children (O) aged 10.2 ± 0.7 years and body mass index (BMI) between the 95th and the 97th percentiles; b) 15 non-obese children (NO) aged 9.8 ± 0.7 years and BMI between the 5th and 85th percentiles. All children were submitted to an anthropometric and clinical assessment, analysis of the HRV at rest and a physical exercise protocol (PEP). Non-parametric tests were used to compare the variables between the groups. The level of significance was set at p < 0.05. RESULTS: The waist circumference and levels of triglycerides were higher in O. The cardiac sympathetic activity in the standing position in normalized units (LF n.u.) was higher in O, 71.4%, when compared to NO, 56.3%. The low frequency/high frequency ratio (LF/HF) was 3.8 in O and 1.7 in NO. The PEP showed differences between the groups, with higher values observed in NO children regarding the total distance, time of exposure to PEP, peak oxygen consumption (VO2 peak) and metabolic equivalent (MET). CONCLUSION: Obesity in children resulted in alterations in cardiac autonomic control in the standing position and decreased the physical capacity.
Autonomic nervous system; obesity; heart rate; exertion
