This study investigated the effects of acute exercise on 53 young (16–24 years) and 47 older (65–74 years) adults’ switch-task performance. Participants practiced sports requiring either low or high cognitive demands. Both at rest and during aerobic exercise, the participants performed two reaction time tasks that differed in the amount of executive control involved in switching between global and local target features of visual compound stimuli. Switch costs were computed as reaction time differences between switch and nonswitch trials. In the low demanding task, switch costs were sensitive only to age, whereas in the high demanding task, they were sensitive to acute exercise, age, and sport-related cognitive expertise. The results suggest that acute exercise enhances cognitive flexibility and facilitates complex switch-task performance. Both young age and habitual practice of cognitively challenging sports are associated with smaller switch costs, but neither age nor cognitive expertise seem to moderate the relationship between acute exercise and switch-task performance.