Want to Keep Your Mind Sharp? Keep Your Body Strong

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About 2,000 years ago, the Roman poet Juvenal famously wrote, "You should pray for a healthy mind in a healthy body" (Orandum est ut sit mens sana in corpore sano). For millennia, we've known that healthy minds and healthy bodies tend to go hand in hand.

Now, the results of a 10-year study (Ward et al., 2021) published on December 21 in the Journal of Neurology, Neurosurgery and Psychiatry suggest that the timeless wisdom of the Latin phrase mens sana in corpore sano could be amended to reflect that keeping our bodies strong may also keep our minds strong.

In many ways, the Latin phrase mens robustus in corpore firmo (a robust mind in a strong body) sums up what David Ward and colleagues discovered after analyzing cognitive decline trajectories among 1,762 older adults (mean age 64.1) over the course of a decade.

Ward is a postdoctoral fellow at Dalhousie University's Division of Geriatric Medicine in Nova Scotia. He conducted this research with colleagues at the University of Exeter using data from UK Biobank.

Frailty Increases Dementia Risk As We Age

Notably, this international team of researchers found that "frailty is strongly associated with dementia risk." In people over 60, the researchers found that those who avoided becoming frail—by making healthy lifestyle choices that kept their bodies strong and fit—had a lower risk of age-related cognitive decline and dementia as they got older.

"People who are more frail report more unhealthy lifestyle behaviors and have an increased risk of developing incident dementia," the authors explain. "To support dementia prevention strategies, we must understand the complex relationships between lifestyle behaviors, frailty, and genetics."

Because genetics play a significant role in dementia risk, Ward et al. explored relationships between study participants' frailty index, healthy lifestyle habits, and polygenic risk scores at the beginning of the study. Then, they compared these factors to incidents of all-cause dementia about eight years after the study began.

After establishing a link between frailty and dementia risk, the researchers pursued two primary objectives. First, they investigated if healthy lifestyle choices had a protective effect that lowered the risk of dementia. Second, they assessed whether different degrees of frailty affect the expression of polygenic dementia risk.

Reducing Frailty by Staying Fit Offsets Dementia Risk

When it comes to lowering dementia risk, healthy lifestyle behaviors that reduce frailty have robust protective benefits. Even if someone has a genetic predisposition for developing dementia, staying physically strong and not becoming feeble reduces dementia risk. Conversely, the frailest study participants in this longitudinal study had the highest risk of developing dementia as they got older, regardless of their genes.

"We're seeing increasing evidence that taking meaningful action during life can significantly reduce dementia risk. Our research is a major step forward in understanding how reducing frailty could help to dramatically improve a person's chances of avoiding dementia, regardless of their genetic predisposition to the condition," Ward said in a news release. The underlying causes of frailty are in themselves preventable.

Based on the latest (2021) findings of this 10-year study, the authors conclude that "frailty should be considered an important modifiable risk factor for dementia." Additionally, in terms of modifying dementia risk, lifestyle habits that boost physical fitness and keep people relatively frailty-free across their lifespan appear to be an effective intervention strategy, even among those at higher genetic risk for age-related cognitive decline.