Access to a running wheel inhibits the acquisition of cocaine self-administration

► Male rats were assigned to sedentary and exercising conditions at weaning and later allowed to self-administer cocaine in free-operant test sessions. ► Exercising rats acquired cocaine self-administration at a slower rate than sedentary rats. ► Relative to sedentary rats, exercising rats emitted fewer active lever presses over 15 days of testing. ► The number of inactive lever presses did not differ between exercising and sedentary rats. ► These data indicate that access to a running wheel inhibits the acquisition of cocaine self-administration.