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

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. Objectives: To assess the effects of HIIT on different anthropometric and cardiovascular parameters of overweight and obese children aged 7-9 years. Material and methods: Four groups were formed: 1) an overweight control group (OWCG, n =30, BMI =21.60 +/- 3.72 kg/m(2)); 2) an obesity control group (OCG, n =34, BMI =23.92 +/- 3.11 kg/m(2)); 3) an overweight intervention group (OWIG, n =69, BMI =20.01 +/- 1.88 kg/m(2)), and 4) an obesity intervention group (OIG, n = 141, BMI =24.12 +/- 2.66 kg/m(2)). BMI, body fat (BF), waist circumference, height-waist ratio, systolic and diastolic blood pressure and cardiorespiratory fitness (CRF) were assessed before and after intervention. Results: There were significant differences in BMI (P<.001), BF (P<.001), and CRF (P<.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<.001) and OIG (BMI, 24.12 +/- 2.66 at baseline vs. 23.23 +/- 3.23 after HIIT, P<.001) groups. Similarly, BF decreased in the OWIG (BF, 21.84 +/- 4.97 at baseline vs. 19.55 +/- 4.81% after HIIT, P<.001) and OIG (BF, 30.26 +/- 11.49 at baseline vs. 26.81 +/- 6.80% after HIIT, P<.001) groups. CRF improved in both intervention groups (P<.001). There was a significant decrease in the prevalence rate of schoolchildren with obesity (from 66.4% to 49.6%) (P<.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. (C) 2019 SEEN y SED. Published by Elsevier Espana, S.L.U. All rights reserved.