A recent study published in JAMA Network Open suggests that increasing physical activity after reaching middle age can lower the risk of developing dementia by as much as 45%. Researchers at Boston University School of Public Health examined data from over 4,300 participants in the Framingham Heart Study, all of whom did not have dementia at the study’s start.
Participants filled out a questionnaire detailing their sleep patterns and physical activity levels (classified as sedentary, light, moderate, or vigorous). The researchers tracked their physical activity in three life stages: early adulthood (ages 26 to 44), midlife (ages 45 to 64), and late adulthood (ages 65 to 88). On average, they followed the participants for about 37.2 years in early adulthood, 25.9 years in midlife, and 14.5 years in late adulthood to observe the onset of Alzheimer’s disease and other forms of dementia.
During this period, individuals who reported high levels of physical activity in midlife had a 40% lower risk of developing all types of dementia over 26 years when compared to those who were the least active. Similarly, higher activity levels later in life were linked to a reduced risk of dementia, falling between 36% and 45% over a span of 15 years.
“These findings could help shape more targeted strategies for preventing or delaying dementia, underlining that the benefits of physical activity may start backing brain health earlier than previously understood,” commented Philip Huang, Ph.D., an author of the study.
Interestingly, the reduced risk of dementia from increased activity in midlife was only noted among individuals who did not possess the APOE4 gene, which is often linked to a higher risk for Alzheimer’s disease. However, for those who engaged in physical activity in later life, both APOE4 carriers and non-carriers showed a diminished risk of dementia.
The connection between exercise and the brain
Dr. Huang discussed various mechanisms that might explain how physical activity lessens dementia risk. Increased exercise is thought to enhance brain structure and function, lower inflammation, and improve vascular health. Furthermore, it may even exert a direct influence on Alzheimer’s pathology, possibly affecting the deposit of harmful beta-amyloid proteins in the brain.
Despite these promising findings, Huang acknowledged a limitation of the study—its reliance on self-reported data regarding physical activity levels. He pointed out that while the results suggest a clear association between higher activity and lower dementia risk, they don’t necessarily translate into concrete advice on specific exercise types.
Moreover, no correlation was found between physical activity in early adulthood and the risk of all-cause dementia or Alzheimer’s disease. The authors noted that the presence of relatively few dementia cases in that age group reduces the power to find a connection with physical activity.
Dr. Kathryn Devons, a geriatrician, praised the findings for supporting the notion that exercise can mitigate dementia risk. She added that regular activity is linked to lower rates of conditions like high blood pressure and diabetes—further risks that can impact brain health.
Overall, while more research is certainly needed to better understand the nuances of these relationships, this study reinforces the idea that maintaining an active lifestyle could play a vital role in promoting cognitive health as we age.
