Modulação autonômica cardíaca em repouso e limiar de variabilidade da frequência cardíaca em jovens com excesso de massa corporal

Abstract

Obese youth are already showing changes in cardiac autonomic modulation, both at rest and in exercise. This study aimed to analyze the cardiac autonomic modulation at rest and exercise in young untrained 18 to 25 years with excess body mass. They evaluated 31 normotensive men not trained, and 10 normal weight (22.75 ± 1.66 kg m-2), 10 overweight (27.03 ± 1.48 kg m-2) and 11 obese (33.70 ± 2.75 kg.m-2). Anthropometric variables were: body mass (BM) and height to later determine the body mass index (BMI), neck circumference, waist, abdomen,% fat (% BF). Systolic blood pressure (SBP) and diastolic (DBP), cardiac autonomic modulation (SD1, SD2, SD1 / SD2, RMSSD, pNN50, VLF, LF, HF, LF / HF, LFun, HFun, the approximate entropy value ( ApnEn), sample entropy (SampEn) were evaluated in a sitting position for 10 minutes and at the end of the capillary glycemia rest was measured. then we performed a maximum incremental test on a cycle ergometer with initial load of 15 watts and increase of 15 watts every minute. The anaerobic threshold (AT) was determined by heart rate variability threshold (HRVT) by two different indices (SD1 and RMSSD), two criteria (Lima; Kiss, 1999 and Karapetial et al, 2008) and the threshold ventilation (VT), the visual method of ventilatory equivalent of O2 and CO2 (VE / VO2 and VE / CO). The one-way ANOVA test with Post Tuckey Hoc was used to analyze the morphological and physiological variables, glycemic profile and autonomic modulation heart at rest and at maximal progressive test between different BMI. The comparison of determined by different indices, criteria and the VT among the different BMI was performed by ANOVA two-way test for repeated measures with post hoc Tuckey. At rest, there were no differences in blood pressure levels, cardiac autonomic modulation, entropy and random blood glucose levels among the different BMI. Among the anthropometric variables waist circumference had the highest association with indexes SD1 and pNN50 HRV. The pNN50 was associated with MC, BMI, neck circumference, waist circumference,% of lean body mass,% fat. It was possible to estimate the VT by the different indices and criteria used and the VT in young untrained with different BMI, with no differences between the groups, which shows the same level of physical fitness, independent of BMI. All LVFC showed good agreement with the VT, and the HRVTSD1 what better presented agreement. The indices of cardiac autonomic modulation at rest, especially in the time domain, joined

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to the load on HRVT, independent of BMI. In short, obese young people have cardiac autonomic modulation, both at rest and in preserved exercise.