Moderate-intensity exercise boosts the N2 neural inhibition marker: A randomized and counterbalanced ERP study with precisely controlled exercise intensity

A prior session of moderate intensity continuous exercise (MCE) benefits performance during tasks requiring conflict resolution but the specific cognitive process that underlies this improvement remains unknown. Many studies postulate that MCE increases inhibition, but ERP evidence is ambiguous due to significant differences across past procedures. Most importantly, exercise intensity, which modulates the relationship between acute exercise and cognitive processes, might have varied across past ERP studies. Additionally, previous procedures may not have sufficiently engaged the inhibition process during tasks. The aim of this study was to assess the effects of an acute exercise session on behavioral (accuracy, RT) and ERP (N2, P3b) indices of cognitive processes engaged in conflict resolution. Contrary to most previous studies, we determined ventilatory thresholds (VTD) in order to precisely control exercise metabolism. Moreover, to ensure engagement of inhibition we used a flanker task in a version eliciting strong conflict. 18 male adults underwent three testing sessions in a randomized and counterbalanced order: moderate-intensity continuous exercise (MCE), high-intensity interval exercise (HIIE), and seated rest condition. After each session participants performed the flanker task, during which EEG data was collected. Compared with the control condition, exercise between the first (VT1) and the second (VT2) ventilatory threshold (MCE), but not exercise that exceeded VT2 (HIIE), improved performance in the task and increased the N2 component, which is a neural marker of inhibition. The study shows that MCE might directly benefit inhibition and shows the need for more precise measures of exercise intensity in future studies.