This study investigates how moderate and addictive exercise influence the executive function network of the brain using fMRI. Sixty-five healthy participants performed the Wisconsin Card Sorting Test (WCST) during a functional magnetic resonance imaging (fMRI) scan. Participants were divided into three groups, according to the Korean exercise addiction scale (K-EAS): addictive exercise (AE), moderate exercise (ME), and no exercise (NE). We compared the extracted volumes of activity from the fMRI data between groups and analyzed the correlation between the volumes and the behavioral data. The activated area in the executive function network was significantly smaller in the AE and ME groups than in the NE group. In contrast, there was no difference between the AE and the ME group in the size of the activated area of the executive function network. The groups did not differ in behavioral performance. There was no significant correlation between the behavioral measurements and the activation volumes. A focused reorganization of the executive brain network through exercise may suggest improved neural efficiency for executive functions, and exercise may be helpful in maintaining executive functions and behavioral performance levels. Addictive exercise did not show an added benefit for the efficiency of executive functions.
