# Effect of 12 Sessions of Short-Duration High-Intensity Interval Training on Executive Function and Inhibitory Control in Healthy Adolescents: A Cluster Randomized Clinical Trial

## TL;DR

A six-week short-HIIT program in Brazilian adolescents did not improve executive function or inhibitory control, despite being safe and feasible.

## Contribution

This study evaluates the effects of school-based short-HIIT on cognitive functions in adolescents using a cluster randomized trial design.

## Key findings

- Twelve 10-minute short-HIIT sessions over six weeks did not significantly improve executive function or inhibitory control in adolescents.
- Both intervention and control groups showed practice effects in cognitive tests, but no differences were found between groups.
- The short-HIIT protocol was safe and not associated with acute injuries.

## Abstract

There is a gap in the evidence regarding the effects of short-duration high-intensity interval training (short-HIIT) on executive and inhibitory functions in adolescents, particularly when using protocols adapted to the school setting and available infrastructure. Therefore, the aim of this study was to investigate the effects of a short-HIIT program on executive function and inhibitory control in Brazilian school adolescents. This was a randomized, single-center clinical trial with intervention and control groups. Adolescents aged 15-17 years participated in a short-HIIT protocol for six weeks. Primary outcomes were executive function and inhibitory control, assessed using the Trail Making Test (TMT) Parts A and B and the Stroop Color Test, respectively. Data were analyzed per protocol and by intention-to-treat. Intervention effects were examined using generalized estimating equations with linear and Poisson models, incorporating time, group, an interaction term, and adjustment covariates. The significance level for two-tailed tests was set at 5%. The sample included 161 students (46 in the short-HIIT group and 115 in the control group). The main results showed absolute reductions in completion times for both the Stroop and TMTs in both groups, consistent with a potential practice effect, with no statistically significant differences between the intervention and control groups at baseline or post-intervention. After 12 sessions, no statistically significant differences were observed between the intervention and control groups for any of the assessed outcomes, in either crude models or models adjusted for confounding variables (sex, age, asset index, baseline physical activity level, time spent on social media, and BMI). In conclusion, twelve 10-minute sessions of short-HIIT performed at the beginning of physical education classes over six weeks did not alter executive function or inhibitory control in adolescents from southern Brazil. Moreover, the adopted HIIT protocol was safe and was not associated with acute injuries.