Heart Rate/physiology – ABC CARDIOL

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Editorial

Analysis of Sensitivity and Specificity of Cutoff Points for Resting Heart Rate in 6,794 Brazilian Adolescents: A Cross-Sectional Study

Luana Anaisse Azoubel et al. Erika Ribeiro Carneiro Nilviane Pires Allan Kardec Barros Carlos José Dias

Resting heart rate (RHR) is an accessible measure that may reflect the balance between the sympathetic and parasympathetic nervous system. Elevated RHR levels are associated with cardiovascular events in adults and cardiovascular risk factors, such as overweight, abdominal obesity and high blood pressure have been associated with high RHR. Therefore, obtaining a cutoff point for the RHR in children and adolescents is essential for better screening and subsequent clinical follow-up.

Furthermore, the early identification and screening of cardiovascular changes and cardiac autonomic modulation can be reflected by simple measures such as the RHR, since sedentary adolescents with abdominal obesity have lower heart rate variability (HRV) and, consequently, greater sympathetic stimulation, maintaining the RHR high and increasing the risk of developing heart damage throughout life.

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Original Article

Cardiac Autonomic Adjustments During Baroreflex Test in Obese and Non-Obese Preadolescents

Mário Augusto Paschoal et al. Aline Carnio Brunelli Gabriela Midori Tamaki Sofia Serafim Magela

Abstract

Background:

Recent studies have shown changes in cardiac autonomic control of obese preadolescents.

Objective:

To assess the heart rate responses and cardiac autonomic modulation of obese preadolescents during constant expiratory effort.

Methods:

This study assessed 10 obese and 10 non-obese preadolescents aged 9 to 12 years. The body mass index of the obese group was between the 95th and 97th percentiles of the CDC National Center for Health Statistics growth charts, while that of the non-obese group, between the 5th and 85th percentiles. Initially, they underwent anthropometric and clinical assessment, and their maximum expiratory pressures were obtained. Then, the preadolescents underwent a constant expiratory effort of 70% of their maximum expiratory pressure for 20 seconds, with heart rate measurement 5 minutes before, during and 5 minutes after it. Heart rate variability (HRV) and heart rate values were analyzed by use of a software.

Results:

The HRV did not differ when compared before and after the constant expiratory effort intra- and intergroup. The heart rate values differed (p < 0.05) during the effort, being the total variation in non-obese preadolescents of 18.5 ± 1.5 bpm, and in obese, of 12.2 ± 1.3 bpm.

Conclusion:

The cardiac autonomic modulation did not differ between the groups when comparing before and after the constant expiratory effort. However, the obese group showed lower cardiovascular response to baroreceptor stimuli during the effort, suggesting lower autonomic baroreflex sensitivity.