The moderating effect of lifetime physical activity on brain alterations related to adverse childhood experiences.

BACKGROUND: Adverse childhood experiences (ACEs) can cause morphological brain alterations across the lifespan, contributing to increased vulnerability to mental and physical disorders. Despite extensive research on ACEs-related brain alterations, the protective or augmenting role of modifiable lifestyle factors such as physical activity has been largely underexplored, representing a key gap in our understanding of trauma-related neuroplasticity. To close this gap, we aimed to investigate how lifetime physical activity (LPA) influences the relationship between ACEs and morphological brain alterations. METHODS: Moderation analyses using Hayes' PROCESS macro examined the interaction between ACEs and LPA on the volume of limbic system-related regions - hippocampus, amygdala, anterior cingulate cortex (n = 81). RESULTS: While LPA showed no moderating effect on hippocampal or anterior cingulate volume, the model concerning the volume of the amygdala was significant. This model explained 8.1% of the variance in amygdala volume (p = 0.002) and the interaction of LPA and ACEs contributed 7.9% of this variance, with a significant effect (β = -0.221 p ≤ 0.001). That indicated LPA moderates ACEs-related structural changes in the amygdala, a key component of the central circuitry of emotion and stress sensitization. Notably, only in individuals with low physical activity were ACEs associated with increased volume of amygdala. CONCLUSIONS: Our findings underscore the behavioral dependency of the structural adaptations of the amygdala following childhood adversities. These results emphasize the therapeutic potential of incorporating physical activity into interventions for trauma-exposed individuals, offering a behavioral approach to mitigating stress-related neurobiological changes.