Abstract
Although there is an abundance of research investigating the effects of exercise on cognition, few studies have investigated acute effects of exercise on performance of tasks involving executive function. Furthermore, dose-response issues involving different exercise intensities and multiple tests of executive function have received little attention. The purpose of the present study was to investigate the effects of varying intensities of aerobic exercise on executive function test performance over a 38-minute follow-up period. University students (N=88) completed baseline measures of executive function (stop-signal task[SST] and Stroop task[ST]) and a graded cardiovascular exercise test on Visit 1. On Visit 2, participants were stratified by gender and fitness level and randomized to one of four conditions: high-intensity interval (HIIT), high, moderate or low-intensity steady-state exercise performed on a cycle ergometer. The ST and SST were performed immediately following exercise and again at 10- and 30-minutes post-exercise. Immediately following exercise, ST response times were faster for the high and moderate intensity exercise conditions in comparison to low-intensity (p < .05), while improvement in SST response inhibition was revealed for the HIIT (p < .01) condition. At 10-minutes post-exercise, moderate and low-intensity conditions revealed improvements in ST response times (p < .05), with enhanced SST response inhibition evident in the HIIT, moderate and low-intensity conditions (p < .05). At 30-minutes post-exercise, ST response times continued to show improvements from baseline for the moderate and low-intensity conditions (p < .05), while SST response inhibition trended towards baseline levels (p > .05). The present outcomes demonstrate beneficial effects of exercise, regardless of intensity, for up to 38 minutes post-exercise. However, no clear dose-response relationship between exercise intensity and executive function performance was evident. Future research should focus on mechanisms that would account for these effects and factors that support enhanced executive function performance with exercise training.
