Autonomic modulation and adjustment of heart rate and heart rate variability during exercise in obese children

Abstract

Childhood obesity has become a serious public health problem and is associated with development of cardiovascular and metabolic comorbidities, among which commits the neurocardíaca function, which highlights the importance of the study of heart rate variability (HRV), a useful tool in the early diagnosis of autonomic dysfunction. Objectives: To investigate cardiac autonomic modulation at rest and adjustments of heart rate (HR) and its variability to submaximal isometric exercise in obese children. Methods: A group of obese children will be subjected to collection of blood samples for analysis of triglycerides, total cholesterol, high density lipoprotein , low density lipoprotein and glucose. The HR and RR intervals (R-Ri) snapshots are recorded at rest with spontaneous breathing in the seated position for twenty minutes and analyzed based on the analysis of the recurrence plot (RP). Two tests of submaximal voluntary isometric contraction (CIVS) will be performed: with 20 % and another with 40 % of maximum strength for two minutes or until exhaustion. The HR and R-Ri will be recorded continuously for 65 s at rest , during isometric contraction and 5 minutes of recovery. From these data the adjustments of HR and its variability during exercise and recovery period will be studied. Assumptions: obese children have lower HR responses during the (vague - dependent), higher in longer durations and slower recovery due changes in autonomic modulation opening seconds.