Daily Exercise In Midlife May Cut Dementia Risk By Nearly Half, Study Finds

A new study published in JAMA Network Open has found that increasing physical activity during midlife or later can significantly reduce the risk of Alzheimer's disease and other forms of dementia. According to researchers from the Boston University School of Public Health, individuals who stay active may lower their dementia risk by as much as 45%.

The study analyzed data from over 4,300 participants of the Framingham Heart Study Offspring cohort. All participants were dementia-free at the beginning of the study and completed detailed questionnaires on their sleep habits and physical activity levels-ranging from sedentary to heavy.

Researchers tracked physical activity at three life stages: early adulthood (ages 26-44), midlife (45-64), and later life (65-88). They followed participants for an average of 37 years in early adulthood, 26 years in midlife, and 15 years in later life.

Findings showed that those with higher levels of physical activity in midlife had a 40% lower risk of developing dementia over a 26-year period. Similarly, high physical activity in later life was linked to a 36% to 45% reduced dementia risk over 15 years.

The study highlights that regular exercise-even started in midlife-can play a powerful role in protecting long-term brain health.

"These results may help to inform more precise and effective strategies to prevent or delay the onset of dementia in later life, and support evidence that the benefits of physical activity on the brain may extend to earlier in life than previously thought," study author Phillip Hwang, PhD, from the Department of Epidemiology at the Boston University School of Public Health, told Fox News Digital.

Higher activity in midlife was associated with lower dementia risk only in people without APOE4, a genetic variant linked to higher Alzheimer's risk.

However, this was not the case with the late-life higher activity group, which showed reduced dementia risk among both APOE4 carriers and those without the gene, according to the study.

"There are several possible mechanisms through which physical activity is thought to lower the risk of dementia, such as improving brain structure and function, reducing inflammation and exerting benefits on vascular function," Hwang told Fox News Digital.

Physical activity may also directly impact Alzheimer's disease pathology, such as the buildup of toxic beta-amyloid in the brain, according to the researcher.

"These potential mechanisms may contribute to facilitating cognitive reserve, which can delay late-life cognitive impairment."

More research is needed to understand whether these possible causes all happen at the same time throughout a person's life, or if different causes emerge at different stages, the researchers said.