# Research on physical activity and dementia risk > Live situation record from CLSTR: https://clstr.news/situations/research-on-physical-activity-and-dementia-risk > Updated: 2026-09-27T09:36:18.000Z. Sources: 7. Developments: 2. Research has increasingly identified connections between physical activity and dementia risk or prevention. An analysis of data from 4.2 million people across 30 countries found that while overall activity reduces dementia risk by 20 percent, the type of movement matters. Recreational exercise was linked to a 24 percent lower risk, whereas physical labor for work was associated with a 20 percent higher risk, a phenomenon described as the “physical activity paradox.” Further research from the University of the Sunshine Coast has identified a specific biological pathway involving the chemical irisin. The study suggests that frequent exercise in older adults is associated with higher irisin levels, which correlates with a larger hippocampus—a brain region critical for memory. This finding provides potential insights into preventing Alzheimer’s disease through lifestyle interventions. ## Timeline ### 2026-09-27: University of the Sunshine Coast study links exercise to dementia prevention University of the Sunshine Coast researchers have found that exercise increases irisin levels in seniors, which is linked to a larger hippocampus and may help prevent dementia and Alzheimer’s. 2 sources. https://clstr.news/cluster/university-of-the-sunshine-coast-study-links-exercise-to-dementia-prevention ### 2026-09-02: University of Southern California study links activity type to dementia risk A University of Southern California study of 4.2 million people found that recreational exercise reduces dementia risk by 24 percent, while physical labor at work is linked to a 20 percent higher risk. 5 sources. https://clstr.news/cluster/university-of-southern-california-study-links-activity-type-to-dementia-risk --- Cite as: Research on physical activity and dementia risk. CLSTR, https://clstr.news/situations/research-on-physical-activity-and-dementia-risk