Across three cohorts totaling over 11,000 participants, plasma proteomics using the SomaScan 7k platform (measuring ~7,000 proteins) identified biological signatures shared between physical activity (PA) and dementia protection. A key protein co-expression module, M12, enriched for extracellular matrix (ECM), neurodevelopmental, and vascular remodeling proteins, was positively associated with both PA levels and cognitive performance while being negatively associated with Alzheimer's disease, Parkinson's disease, and frontotemporal dementia across multiple independent clinical cohorts. M12 proteins also predicted antemortem cognitive trajectory and mapped onto post-mortem brain tissue proteomic signatures in the ROSMAP cohort.
This work moves beyond behavioral epidemiology into mechanistic territory, offering one of the most comprehensive plasma proteomic interrogations of exercise-dementia biology to date. The ECM and vascular remodeling signal is compelling — it aligns with preclinical evidence that exercise promotes neurovascular integrity, synaptic plasticity, and glymphatic clearance. The immune and lipid metabolism signatures echo emerging theories that peripheral metabolic reprogramming from exercise modulates neuroinflammation. Practically, these proteins could function as both mechanistic biomarkers validating exercise interventions in trials and potential therapeutic targets for sedentary or mobility-limited individuals. Limitations include the cross-sectional design of the primary discovery cohort (n=65), which constrains causal inference, and reliance on self-report in the largest cohort. Still, the cross-validation across naturalistic, self-reported, and interventional exercise cohorts substantially strengthens credibility. This is an incremental-to-significant advance — not paradigm-shifting alone, but a strong foundation for targeted mechanistic follow-up.
