Comprehensive cardiac evaluation to maximal exercise in a contemporary population of prepubertal children.

Abstract

Heart rate (HR) is a biomarker used to measure physiological function, health status and cardiovascular autonomic function. The purpose of this study was to determine sex- and age-specific reference values for cardiac autonomic function at rest, during maximal exercise and the recovery phase in prepubertal children. Five hundred and twelve healthy children 7-11 years of age performed a Léger test. A heart RR-interval monitor recorded the heart data and a specific software analysed the cardiac autonomic response through HR and HR variability (HRV). It analysed HR before the test (resting HR, RHR), during the test (HR_peak) and HR recovery (HRR) in the first minute (HRR1) and the fifth minute (HRR5). The values are mean ± SD. Collectively, 91.2% of girls and 92.3% of boys were within the recommended ranges regarding RHR. The average HR_peak was 199 ± 10.83 b.p.m. and 96.8% of girls and 95.3% of boys were within the minimum threshold value recommended (180 b.p.m.). Boys showed lower values of RHR than girls (p < 0.001) and larger values of HRR 1 and HRR5 (p < 0.001). This study comprehensively provides a reference set of data for the most important HR variables that can be obtained during exercise testing in prepubertal children regarding age and sex and in a field setting. This is the first study to provide reference values of autonomic cardiac function at rest, during maximal exercise and during the recovery period in prepubertal children aged 7-11 years. Despite the early age of participants, cardiorespiratory fitness, RHR and HRR are different according to sex. Aerobic performance and HR_peak have a negative correlation with body mass index and cardiometabolic risk.