Targeting Alzheimer’s Disease Through Physical Activity: A Systematic Review of Biological Mechanisms and Clinical Evidence

Background: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and memory impairment, representing a major global health challenge. With no definitive cure currently available, preventive strategies targeting modifiable risk factors have gained increasing attention. This study presents a systematic review of the role of physical activity in the prevention of Alzheimer’s disease, focusing on underlying biological mechanisms, epidemiological evidence, and exercise modalities. Methodology: A structured literature search was conducted across major databases, including PubMed, Web of Science, and Google Scholar, covering studies published between 2020 and 2024. Eligible studies included observational studies, randomized controlled trials, and systematic reviews examining the relationship between physical activity and cognitive outcomes. Results: Findings indicate that regular physical activity is associated with a reduced risk of Alzheimer’s disease and improved cognitive function. Mechanistically, exercise promotes neurogenesis, enhances brain-derived neurotrophic factor (BDNF) expression, improves cerebral blood flow, and reduces neuroinflammation and oxidative stress. Aerobic exercise, resistance training, and mind-body interventions all demonstrate beneficial effects, with combined exercise approaches showing the greatest impact. Conclusion: In conclusion, physical activity represents a cost-effective, accessible, and non-pharmacological strategy for reducing Alzheimer’s disease risk. Future research should focus on standardising exercise protocols and establishing causal relationships through long-term randomised trials.