Effects of 28 weeks of high-intensity interval training during physical education classes on cardiometabolic risk factors in Chilean schoolchildren: a pilot trial.

The purpose of this investigation was to determine the effects of 28 weeks of high-intensity interval training (HIIT) during physical education classes on the weight status, cardiorespiratory capacity, and blood pressure of overweight and obese schoolchildren. The participants included 197 schoolchildren (108 girls and 89 boys) aged between 6 and 11 years (8.39 ± 1.15 years) in four groups: experimental group 1 (EG1) = 59 overweight schoolchildren; experimental group 2 (EG2) = 92 obese schoolchildren; control group 1 (CG1) = 17 overweight children; and control group 2 (CG2) = 29 obese schoolchildren. The participants in the EGs carried out HIIT twice per week for 28 weeks. After the 28-week intervention, the participants showed significant reductions in body mass index (p < 0.001). Waist circumference of boys in EG2 and waist-to-height ratio of girls in EG2 was significantly reduced (p < 0.05). Body fat percentage diminished, for girls in both groups and boys in EG2 (p < 0.05). Furthermore, the program significantly reduced the number of hypertensive schoolchildren (p = 0.001) and reduced the percentage of obese schoolchildren. The distance covered in the 6-min walk test improved significantly for girls in EG1 and EG2 (p < 0.05) and boys in EG2.

CONCLUSIONS: The 28-week HIIT program caused significant improvements in the cardiorespiratory capacity, anthropometric variables, and blood pressure levels of overweight and obese children. What is Known: • High-intensity interval training (HIIT) programs improve health, but investigations have used relatively short intervention periods. What is New: • The 28-week period (a large intervention period) of HIIT-based games during physical education classes caused significant improvements in cardiorespiratory capacity, anthropometric variables, and blood pressure levels of overweight and obese schoolchildren.