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

BACKGROUND: 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. METHODS: 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 (HRpeak) and HR recovery (HRR) in the first minute (HRR1) and the fifth minute (HRR5). The values are mean ± SD. RESULTS: Collectively, 91.2% of girls and 92.3% of boys were within the recommended ranges regarding RHR. The average HRpeak 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). CONCLUSIONS: 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. IMPACT: 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 HRpeak have a negative correlation with body mass index and cardiometabolic risk.

Active commuting is associated with a lower risk of obesity, diabetes and metabolic syndrome in Chilean adults.

Background: There is limited evidence on how active commuting is associated with health benefits in developing countries. The aim of this study therefore was to investigate the associations between active commuting and markers of adiposity and cardiometabolic risk in the Chilean adult population. Methods: In total, 5157 participants from the Chilean National Health Survey 2009-10 were included in this cross-sectional study. Active commuting was measured using the Global Physical Activity Questionnaire (GPAQ v2). Body mass index (BMI) and waist circumference (WC) were measured and used to define obesity and central obesity. Type 2 diabetes (T2D) and metabolic syndrome were determined using WHO and updated ATPIII-NCEP criteria, respectively. Results: The main finding of this study is that a 30 min increase in active commuting is associated with lower odds for BMI > 25.0 kg m-2 (0.93 [95% CI: 0.88-0.98, P = 0.010]). Similarly, the odds for central obesity was 0.87 [0.82-0.92, P < 0.0001]. Similar associations were found for T2D (0.81 [0.75-0.88], P < 0.0001) and metabolic syndrome (OR: 0.86 [0.80-0.92], P < 0.0001). Conclusion: Our findings show that active commuting is associated with lower adiposity and a healthier metabolic profile including lower risk for obesity, diabetes and metabolic syndrome.