Even small increases in daily walking could make a big difference for brain health, according to new research from Mass General Brigham.
Scientists found that older adults who took more daily steps experienced slower cognitive decline and delayed signs of Alzheimer’s disease — especially those already at higher risk.
The study, published in *Nature Medicine*, showed that people who walked between 3,000 and 5,000 steps each day delayed cognitive decline by about three years. Those who managed between 5,000 and 7,500 steps a day saw an even greater benefit, with a delay of roughly seven years.
By contrast, people who were mostly inactive showed faster buildup of harmful tau proteins in the brain and experienced more rapid memory loss and difficulty performing everyday tasks.
Dr. Jasmeer Chhatwal, a neurologist at Mass General Brigham and senior author of the study, explained that these findings help clarify why some people at risk of Alzheimer’s decline faster than others.
“Lifestyle factors appear to impact the earliest stages of Alzheimer’s disease, suggesting that lifestyle changes may slow the emergence of cognitive symptoms if we act early,” he said.
The research was part of the long-running Harvard Aging Brain Study, which followed 296 people between ages 50 and 90 who showed no signs of cognitive impairment when the study began.
Participants wore pedometers to track their daily physical activity and received brain scans to measure levels of amyloid-beta and tau — the two key proteins involved in Alzheimer’s disease. They also completed annual cognitive tests for up to 14 years, with an average follow-up of more than nine years.
The results revealed that people who had higher levels of amyloid-beta but were more physically active experienced a slower buildup of tau in the brain. This suggests that walking and other forms of regular movement can slow down the brain changes that eventually lead to Alzheimer’s symptoms.
Among people with low amyloid-beta levels, activity levels did not make much difference, possibly because their risk for developing Alzheimer’s was already lower.
Dr. Reisa Sperling, co-principal investigator of the Harvard Aging Brain Study, said the results highlight the importance of staying active as we age.
“These findings show us that it’s possible to build cognitive resilience and resistance to tau pathology in the setting of preclinical Alzheimer’s disease,” she explained. “This is particularly encouraging as we continue our quest to prevent Alzheimer’s dementia.”
The team plans to continue studying how different types and intensities of physical activity affect brain health. They also aim to uncover the biological mechanisms that connect movement, tau accumulation, and cognitive decline.
Future research may test whether specific exercise programs can be prescribed as part of early prevention strategies for people at risk of Alzheimer’s.
First author Dr. Wai-Ying Wendy Yau, a cognitive neurologist at Mass General Brigham, said the message is simple: “Every step counts. Even small increases in daily activity can build over time to create lasting benefits for brain and cognitive health.”
The study provides one of the clearest long-term pictures yet of how everyday physical activity influences the brain. By showing that a few thousand steps a day can delay the biological changes that drive Alzheimer’s, it offers hope that people can take meaningful action to protect their minds as they age.
In summary, the research strengthens the growing evidence that lifestyle habits—especially regular walking—can shape how the brain ages.
While there is still no cure for Alzheimer’s, maintaining an active lifestyle appears to slow its progression and preserve quality of life for longer. Experts agree that these results make a strong case for seeing movement not just as exercise, but as medicine for the brain.
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The study is published in Nature Medicine.
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