Exercise in Mid- or Late Life May Cut Dementia Risk by Up to 45%

One of the most common worries about aging is losing one's memory — and one of the most encouraging research messages is that we have more control over that risk than once believed. A study led by Boston University, published in JAMA Network Open in January 2026, adds fresh weight to that idea, finding that staying physically active in mid- or later life is associated with a substantially lower risk of dementia.

The researchers drew on more than 1,500 participants in the Framingham Heart Study, a landmark, decades-long research project. They found that a high level of physical activity in mid-life — roughly ages 45 to 64 — was associated with a 45% lower risk of developing dementia, while high activity in late life — about ages 65 to 88 — was linked to a 41% lower risk. The strength of the association at both stages is the heart of the good news.

The practical takeaway is genuinely freeing. "It's never too late to start," noted lead author Phillip Hwang, an assistant professor of epidemiology at BU's School of Public Health, emphasizing that even people who become active later in life appear to benefit. He added that "finding ways to be more active and moving around is important, especially if more time is typically spent being sedentary" — a reminder that small, sustainable changes count.

As with all observational research, some caution is warranted. The study shows a strong association, not definitive proof that exercise alone prevents dementia, and people who are more active may differ in other ways that affect brain health. Physical activity is also one of several protective factors, alongside sleep, diet, social connection and managing blood pressure. Even so, the finding reinforces a hopeful and accessible message: moving your body, at almost any age, is one of the best things you can do for your future brain.