Effort intensification and restoration in short-term HIIT predict strategic control in complex tasks

High-Intensity Interval Training (HIIT) is known to positively impact cognitive function; however, there is currently no empirical evidence directly linking the exercise interval patterns and durations to executive function. The objective of this study is to critically evaluate the positive effects of HIIT on cognitive function, specifically focusing on the influences of exercise intensity and interval patterns. Eighty-five participants were randomly assigned to four different HIIT protocols based on a 2 (exercise time) × 2 (interval time) repeated-measures experimental design. Inhibitory function (IF) was assessed using Eriksen flanker tasks, congruent and incongruent, before and after exercise. The weighted reaction time (WRT) served as a measure of the ability to process information accurately. The nonparametric Kruskal-Wallis test was employed to compare differences in WRT and IF across baseline, pre-test, and post-test conditions. The Generalized Linear Mixed Model (GLMM) was used to identify factors influencing changes in IF (IF_delta) between pre-test and post-test. Additionally, the average variance decomposition method quantified the proportion of explained variance. The restricted cubic spline (RCS) method confirmed a strict linear relationship between changes in IF and WRT in the incongruent task. Results indicated significant differences in WRT-related variables across all HIIT types when comparing baseline, pre-test, and post-test at the Flanker congruent task (P < 0.05) and in the post-test at the Flanker incongruent task (P < 0.05). Higher-intensity exercise resulted in a significant decrease in WRT (P < 0.001). The WRT during the Flanker incongruent task was the primary factor influencing IF_delta, demonstrating a strict linear relationship as evidenced by the GLMM, RCS, and linear fitting results. In conclusion, significant gender differences were observed in IF-related variables. WRT is a reliable indicator that has a direct linear relationship with IF, particularly regarding the ability to perform complex tasks. The interval pattern of HIIT affects the magnitude of cognitive benefits, while exercise intensity influences the rate of change in mental performance.