Exercise is increasingly recognized as a significant factor in preventing or reducing the risk of dementia, including Alzheimer’s disease. This recognition comes from a body of research that has explored the relationship between physical activity and cognitive health across various stages of life.

Physical inactivity is identified as a modifiable risk factor for dementia. Studies have shown that engaging in regular physical activity can reduce the risk of developing dementia by about 28% and for Alzheimer’s disease specifically, the risk reduction can be as much as 45%. This evidence is drawn from analyses that combined the results of 16 studies, highlighting the considerable impact exercise can have on preventing cognitive decline​ (Alzheimer’s Society)​.

The mechanisms behind how exercise can influence cognitive health and prevent dementia are multifaceted. Physical activity has been shown to improve thinking and memory in middle-aged and older adults, potentially by promoting brain health through the improvement of blood flow, reducing inflammation, and enhancing the brain’s ability to maintain old network connections while creating new ones. Despite this promising evidence, some studies have yielded mixed results regarding the direct impact of exercise interventions on improving activities of daily living, physical activity, or quality of life in individuals already experiencing mild cognitive impairment or early dementia​ (BMJ)​.

Moreover, an intensive program of exercise and functional activity training, aimed at promoting activity, independence, and stability in individuals with early dementia or mild cognitive impairment, did not show significant improvements in reducing falls or improving secondary health status outcomes. This suggests that while exercise has clear benefits for preventing cognitive decline in healthy individuals, its effectiveness as a therapeutic intervention for those already experiencing cognitive impairment may require further investigation​ (BMJ)​.

In summary, the consensus among researchers and health practitioners is that maintaining an active lifestyle plays a crucial role in reducing the risk of dementia and cognitive decline. This includes not just preventing the onset of such conditions but possibly slowing their progression in those who are already affected. A lifelong approach to good health, incorporating regular physical activity, is advocated as the best strategy for lowering the risk of dementia​ (Alzheimer’s Society)​.

Given the complexity of dementia and the factors contributing to its development, further research is needed to fully understand the extent of exercise’s benefits and to develop targeted interventions that can effectively support cognitive health across the lifespan.