Response of obese schoolchildren to high-intensity interval training applied in the school context

Abstract

Background: High-intensity interval training (HIIT) has been widely used to fight cardiovascular risk factors in adolescents and adults, but no data are available on its applicability in children. Objective: To assess the effects of HIIT on different anthropometric and cardiovascular parameters of overweight and obese children aged 7---9 years. Subjects and methods: Four groups were formed: 1) an overweight control group (OWCG, n = 30, BMI = 21.60 ± 3.72 kg/m2), 2) an obesity control group (OCG, n =34, BMI = 23.92)±3.11 kg/m2), 3) an overweight intervention group (OWIG, n = 69, BMI = 20.01±1.88 kg/m2), and 4) an obesity intervention group (OIG, n = 141, BMI = 24.12±2.66 kg/m2). BMI, body fat (BF), waist circumference, height-waist ratio, systolic (SBP) and diastolic (DBP) blood pressure and cardiorespiratory fitness (CRF, were assessed before and after intervention. Results: There were significant differences in BMI (P < 0.001), BF (P < 0.001), and CRF (P < 0.001) between the groups (control vs intervention) before and after intervention (OWCG vs OWIG and OCG vs OIG). BMI decreased in the OWIG (BMI, 20.01±1.88 at baseline vs 19.00±2.02 after HIIT, P < 0.001) and OIG (BMI, 24.12±2.66 at baseline vs 23.23±3.23 after HIIT, P < 0.001) groups. Similarly, BF decreased in the OWIG (BF, 21.84±4.97 at baseline vs 19.55±4.81 % after HIIT, P < 0.001) and OIG (BF, 30.26 ±11.49 at baseline vs 26.81±6.80 % after HIIT, P < 0.001) groups. CRF improved in both intervention groups (P < 0.001). There was a significant decrease in the prevalence rate of schoolchildren with obesity (from 66.4% to 49.6%) (P < 0.001). Conclusion: The intervention conducted in the school setting improved the anthropometric and cardiovascular parameters of schoolchildren, and also allowed for reducing the proportion of schoolchildren with obesity.