Purpose. We investigated the effects of a two-week high-intensity interval training (HIT) on cognition in adolescents.

Methods. The participants were recruited from local high schools with an electronic messaging system. The HIT group participated in 4 high-intensity interval running sessions and 2 circuit training sessions. The control group (CG) continued their usual habits. Reaction time, choose reaction time, working memory, visual memory, and learning were assessed by computerized CogState test battery. The intervention effect was investigated with repeated measures ANOVA and the effect size by Morris dppc2.

Results. The total of 25 participants aged 17–20 years participated in the baseline measurements and were randomized into the intervention (n = 12) and control (n = 13) groups; 9 people in the HIT group and 10 in the CG also participated in the follow-up assessments. Reaction time (mean change [SD] = 0.02 [0.03] vs. −0.05 [0.08], p for time*group interaction = 0.025, d_ppc2 = −0.297) and choice reaction time (0.03 [0.03] vs. −0.01 [0.04], p for time*group interaction = 0.017, d_ppc2 = −0.874) improved more in the CG than in the HIT group. While we found no other statistically significant time*group interactions, intervention turned out to have a small negative effect on working memory (d_ppc2 = −0.470) and a small positive effect on visual memory and learning (d_ppc2 = 0.419).

Conclusions. The study on HIT produced mixed effects on cognition in adolescents. Studies with a longer intervention period and larger sample sizes are warranted to further explore HIT effects on cognition.