Physical Activity and the Volume of Different Brain Regions and Structures in Older Adults: A Systematic Review and Meta-Analysis

BACKGROUND: The aging process is accompanied by a decline in brain volume, which represents a significant risk factor for the onset of dementia in older adults. Evidence demonstrates that physical activity (PA) can help prevent and attenuate this reduction in brain volume. However, there is no consensus in the scientific literature regarding which specific brain regions and structures are most affected by PA. This systematic review aimed to summarize observational cross-sectional studies examining the association between PA and brain volume in healthy older adults, and to highlight the regions and structures most consistently impacted. METHODS: This review (PROSPERO: CRD420251002199) encompassed the PubMed, Web of Science, and Embase databases and adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eligible studies met the following criteria: observational design, PA assessment (via questionnaires or device-based measures), brain volume quantification, and participants aged 60 years or older. RESULTS: Nineteen studies, totaling 2,684 older adults (mean age = 70 ± 6 years), were included. Across the included studies, 76 brain regions or structures were analyzed, with white matter hyperintensities, total brain volume, white matter, intracranial volume, and total hippocampal volume being the most frequently evaluated. The studies demonstrated moderate methodological quality, with an average score of 4.6 ± 0.9 out of 9 points on the Newcastle-Ottawa Scale. Accelerometers were the predominant method for assessing PA, and all studies used magnetic resonance imaging to evaluate brain structures. CONCLUSION: The evidence synthesized in this review indicates a substantial body of observational research demonstrating an association between higher levels of PA and greater brain volume in specific regions among healthy older adults.