Walking and Alzheimer’s: A simple daily walk may help slow the biological hallmarks of Alzheimer’s, and the memory decline that follows, according to a long-running study led by Mass General Brigham and published in Nature Medicine. Researchers tracked 296 adults (ages 50–90) in the Harvard Ageing Brain Study for up to 14 years, pairing step counts from wearable devices with repeated cognitive testing and PET scans for amyloid and tau, the proteins tied to Alzheimer’s pathology.
Activity didn’t move the needle on amyloid, but it was consistently linked to slower tau buildup and gentler cognitive decline. The sweet spot was modest: averaging 5,000 to 7,500 steps a day correlated with a clear slowdown in both tau accumulation and memory loss. Benefits were detectable from 3,000 to 5,000 steps, then plateaued beyond roughly 7,500, suggesting you don’t need marathon numbers to see an effect.
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Because participants entered the study cognitively normal, the results speak to prevention and early intervention. The authors argue that physical inactivity is a realistic target for changing the disease trajectory, especially in older adults who are sedentary and at higher risk. Wearable step trackers, they note, offer a simple way to set and sustain attainable goals.
The study is observational, so it can’t prove causation, and people who walk more may practice other healthy habits. Still, the signal persisted after accounting for key confounders, and it maps onto growing evidence that regular, moderate activity supports brain health by improving vascular function, reducing inflammation, and maintaining metabolic fitness.
