Neurostructural Correlates and Impulsive Mechanisms of Exercise Dependence in Middle-Aged and Elderly Adults: Evidence from Gray Matter and Structural Covariance Networks

Exercise dependence is characterized by excessive, uncontrollable exercise behavior accompanied by physiological or psychological symptoms. While its existence has been confirmed in young adults, it remains unclear whether the middle-aged and elderly adults exhibit similar neural structural correlates. This study aimed to identify neurostructural changes and the underlying impulsive mechanisms of exercise dependence in middle-aged and elderly adults. A total of 135 participants underwent structural magnetic resonance imaging (MRI) and completed psychological assessments. Whole-brain regression, partial correlation, and mediation analyses were conducted to examine neurostructural changes related to exercise dependence, controlling for gender, age, family socioeconomic status (SES), exercise intensity, and the Big Five Inventory (BFI). Whole-brain analysis of gray matter volume (GMV) revealed that exercise dependence was positively correlated with frontal lobe volume and negatively correlated with occipital cortex volume. Nodal centrality changes aligned with GMV findings. Graph theory analysis indicated that the structural covariance network tended toward a random state. Mediation analysis suggested that impulsivity may be a mechanism linking brain structure to exercise dependence. This study provides initial evidence of neurostructural markers underlying exercise dependence in the middle-aged and elderly adults, demonstrating associations with regional GMV and whole-brain structural covariance networks. These findings propose unique neural mechanisms of behavioral addiction in middle-aged and elderly adults, contributing to addiction research and offering new directions for future studies.