Could Exercise Prevent Dementia?

Given that most individuals are not at genetic risk, physical exercise may be an effective strategy for preventing dementia, according to a new study. However, more research is needed to determine the implications from a public health perspective.

“Although our cognitive ability will inevitably decline with age, there are individual differences in the rate of that decline that are influenced by both genetics and lifestyle,” said study author Jennifer J. Heisz, assistant professor in the Department of Kinesiology at McMaster University in Hamilton, Canada. “We can modify aspects of our lifestyle to help mitigate our risk. Most of us know that exercise is good for our physical health, but it’s also good for our cognitive health.”

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Researchers assessed the interactive relationship of apolipoprotein E (APOE) genotype and physical exercise on dementia risk over a 5-year period in 1646 older adults from the Canadian Study of Health and Aging who were dementia-free at baseline. Physical exercise moderated the relationship between genotype and dementia. Specifically, for APOE ɛ4 noncarriers, the odds of developing dementia were higher in nonexercisers than exercisers, whereas, for APOE ɛ4 carriers, the odds of developing dementia were not significantly different between nonexercisers and exercisers.

“Importantly, the people who were physically active in this sample reported walking 3 times per week, which means you don’t have to train like an Olympian to get the brain health benefits of being physically active,” said Dr Heisz, while noting that many questions still remain. “If a physician were to ask us today what type of exercise she should prescribe for a patient to reduce the risk of dementia, the honest answer is we really don’t know. In an ongoing study, we are comparing the benefits of high-intensity interval training versus moderate continuous training versus stretching in older adults.”

Because physical activity guidelines for brain health do not exist yet, she suggested that individuals follow the guidelines for physical health that recommend at least 150 min of moderate to vigorous aerobic physical activity per week.

—Mike Bederka

Reference:

Fenesi B, Fang H, Kovacevic A, Oremus M, Parminder R, Heisz JJ. Physical exercise moderates the relationship of apolipoprotein E (APOE) genotype and dementia risk: a population-based study [published online November 29, 2016]. J Alzheimers Dis. doi:10.3233/JAD-160424.