Comparação da sensibilidade barorreflexa e variáveis hemodinâmicas entre escolares de 6 a 9 anos obesos e eutróficos

Abstract

Introduction: Obesity affects increasingly younger children and may be associated with increased blood pressure (BP). Baroreflex sensitivity (BRS) is the main short-term BP control mechanism and may be decreased in obese children. Objectives: To compare spontaneous BRS and hemodynamic variables (HV) of normotensive, obese and eutrophic children. Materials and methodology: The sample of children aged between 6 and 9 years old were divided into two groups: obese (BMI-z> 2, n = 16) and normal weight (BMI-z - 2 and 1; n = 15). A 5 minute BP beat to beat record (Finometer) and electrocardiogram (Biopac) were used to calculate the BRS (sequential method) and HV. All measurements were recorded spontaneously after 10 minutes of rest in the supine position. Results: The BRS (p = 0,28) and the baroreflex effectiveness index (p = 0,44) were not significantly different between the groups. The obese group was significantly higher than the normal weight group for systolic blood pressure (105,38 ± 5,96 and 95,33 ± 5,62, p <0.05), diastolic blood pressure (65,56 ± 7,26 and 57,33 ± 5,62; p <0,05) and cardiac output (1,54 ± 0,26 and 1,34 ± 0,21; p <0,05). The heart rate, although not reaching a significant difference, was also higher in the obese group (p = 0,14). Negative correlations were found between systolic blood pressure and BRS (r = -0,52, p = 0,03) in the obese group and between HR and BRS in the obese group (r = - 0,67, p = 0,004) and eutrophic (r = -0,62, r = 0,013). Conclusion: The BRS was not altered by the influence of obesity in the study group. However, high BP, cardiac output and HR values suggest change in the sympathetic function in the obese group. It seems that the damage to the BP, caused by obesity, precede the baroreflex impairment.