HIITing Health in School: Can High Intensity Interval Training Be a Useful and Reliable Tool for Health on a School-Based Enviroment? A Systematic Review

Context: High-intensity interval training (HIIT) is considered a time-eÿcient strategy to improve cardiometabolic health markers in children and adolescents. However, the evidence regarding the characterization of each intervention and the quantification of their health e ects within the school environment is required. Objectives: To systematically review the characteristics of HIIT-based interventions during school time and quantify their e ects on the health of children and adolescents. Data Sources: Recommendation of PRISMA for systematic review was applied. The protocol was registered in the PROSPERO repos-itory 2018 CRD42018089017. A search of the literature (2008 - 2018) on the databases PubMed, Web of Science, CINHAL and PsycINFo was carried out. Study Selection: Twelve publications using HIIT on children and adolescents in a school-based environment were selected. The inclusion criteria were: (1) HIIT; (2) intervention and, (3) type of study. Data Extraction: The inclusion criteria to the titles and abstracts, or three independent researchers analyzed the articles. PRISMA’s recommendation for systematic reviews, Cochrane tool and ROBINS for randomized and non-randomized studies were used. Results: We identified 12 studies that included a total of 917 children and adolescents; 83% of the interventions were performed during physical education classes. The average duration and intensity of the interventions were 8 weeks and > 90% HR, respectively. The most important variables evaluated and impacted by HIIT were cardiovascular fitness, nutritional status, and physiological wellbeing. Conclusions: HIIT seems to be a reliable and time-eÿcient approach to impact especially cardiovascular fitness of children and adolescents during school time. The focus on class intensity and the number of repetitions needs further investigation to find in-terventions based on each school due to individual di erences regarding time and implementation constraints to impact health parameters.