OBJECTIVES: To explore the impact of short-term exercise of varying intensity on traditional risk factors for cardiometabolic disease.
STUDY DESIGN: A total of 109 children (mean age, 11.1 ± 0.8 years) were conveniently assigned to 5 weeks of moderate-intensity continuous training (MICT; n = 29) set at 65%-70% of maximum heart rate, high-intensity interval training (HIIT; n = 29; >80% maximum heart rate), combined training (HIIT + MICT; n = 27), or no training (control; n = 24). Two-way ANOVA (group × time) was used to evaluate the effects of training on all cardiometabolic disease risk factors. Effect sizes were calculated to assess the magnitude of difference.
RESULTS: MICT, HIIT, and HIIT + MICT were associated with significantly improved resting heart rate (effect size, -0.4, -1.1, and -1.1, respectively; P < .0001), fasting glucose (effect size, -0.6, -0.9, and -0.1, respectively; P = .0004), peak oxygen consumption (effect size, 0.5, 0.9, and 0.5, respectively; P < .0001), and c-reactive protein (effect size, -0.2, -1.0, and -0.5, respectively; P = .0016). HIIT + MICT was significantly associated with reduced waist circumference (-5.4%; P < .0001) and waist-to-hip ratio (-2.5%; P < .0002) compared with MICT (7.0% and 6.3%, respectively) and HIIT (-0.5% and -1.3%, respectively).
CONCLUSION: Short-term HIIT and MICT interventions are useful for improving cardiometabolic health in children. HIIT + MICT may provide superior reductions in central obesity indicators.