High intensity interval training improves fitness in children and adolescents

1. Compared to low to moderate intensities of exercise, high intensity interval training (HIIT) either in connection with physical education class (intra-PE) or as extracurricular sport activities (extra-PE) improved neuromuscular and anaerobic performance as well as improved fasting levels of glucose in school children.

2. Neither form of HIIT led to greater improvements in indicators of cardiovascular fitness and in body composition compared to control interventions.

Evidence Rating Level: 1 (Excellent)

Though children and adolescents spend most of their day in school, they do not perform the recommended amount of physical activity. HIIT has previously been shown to induce favorable cardio metabolic and fitness adaptations in this population. Although students may be involved in either intra-PE or extra-PE forms of HIIT, there has not yet been a systematic review and meta-analysis summarizing these effects on children and adolescents. As a result, the objective of the present study was to address this gap and provide a quantitative analysis of the effects of intra- and extra-PE HIIT interventions on fitness and metabolic outcomes in 5-18 year olds.

Of 108 identified studies, 11 were included (n=1095 participants) from 2019-2021. Studies were included if they evaluated the effects of HIIT (either in connection with physical education classes or in other contexts) on fitness or cardio metabolic parameters, and had healthy participants aged 5-18 years. Study quality was assessed using the Physiotherapy Evidence Database (PEDro) scale. Pooled standard deviations, standard mean differences and Hedge’s g effect sizes were calculated.

Results demonstrated that compared to low to moderate intensities of exercise, intra-PE and extra-PE HIIT improved neuromuscular and anaerobic performance as well as improved fasting levels of glucose in school children. Neither form of HIIT lead to greater improvements in indicators of cardiovascular fitness and in body composition compared to the control interventions. However, the study was limited by variability in the exercise protocols and information concerning the interventions (e.g., type, intensity, duration). Nonetheless, the results of this review provided insight into the effects of intra- and extra-PE HIIT on both fitness and cardio metabolic parameters in school aged children.

Click to read the study in Sports Medicine – Open 

Image: PD

©2022 2 Minute Medicine, Inc. All rights reserved. No works may be reproduced without expressed written consent from 2 Minute Medicine, Inc. Inquire about licensing here. No article should be construed as medical advice and is not intended as such by the authors or by 2 Minute Medicine, Inc.