The present study aims at deciphering the effect of a high-intensity interval exercise on cognitive processes involved in perceptual decision-making through computational modelling. To that end, participants performed a perceptual decision task (RDK) before and after a high-intensity interval exercise (8 × 5min, 85 ± 8 % HRmax). Cognitive processes were measured by best-fitting parameters of a drift diffusion model (DDM) to behavioral data (accuracy and response times). Drift Diffusion modeling revealed faster non-decisional time and more efficient drift rate suggesting a better sensory encoding, a greater allocation of attentional resources and a faster processing speed following acute exercise.