A Mass General Brigham–led study published in Nature Medicine suggests that modest daily walking is associated with delayed cognitive decline among older adults at risk for Alzheimer’s disease. Model-based estimates link 3,000–5,000 daily steps with about a three-year delay and 5,001–7,500 steps with roughly seven years.
New research in Nature Medicine reports that higher daily step counts were associated with slower cognitive decline in cognitively unimpaired older adults who had elevated amyloid-beta, an early marker of Alzheimer’s disease. The analysis, from Mass General Brigham investigators, found benefits plateaued around 5,001–7,500 steps per day. The study is observational and does not prove causation. (nature.com)
Researchers examined 296 participants aged 50 to 90 from the Harvard Aging Brain Study who had no cognitive impairment at baseline. Participants wore pedometers to measure daily steps (reported as waistband devices in institutional coverage), underwent PET scans to assess amyloid and tau, and received annual cognitive testing for a median of about nine years (range two to 14). (nature.com)
Using statistical models, the team estimated that among people with elevated amyloid, those walking 3,001–5,000 steps per day would reach a threshold for cognitive worsening about three years later than inactive peers, and those walking 5,001–7,500 steps about seven years later. The associations with slower decline appeared to be mediated primarily by a slower buildup of tau, rather than changes in amyloid. (nature.com)
“This sheds light on why some people who appear to be on an Alzheimer’s disease trajectory don’t decline as quickly as others,” said senior author Jasmeer Chhatwal, MD, PhD. “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.” Co-author Reisa Sperling, MD, said the work suggests it may be possible to build cognitive resilience and resistance to tau pathology in preclinical disease. First author Wai‑Ying Wendy Yau, MD, added, “Every step counts — and even small increases in daily activities can build over time to create sustained changes in habit and health.” (massgeneralbrigham.org)
In contrast, sedentary participants showed faster accumulation of tau protein and more rapid declines in cognition and day-to-day functioning. The authors emphasize that randomized trials are needed to test whether increasing physical activity can directly slow disease processes. (news.harvard.edu)
Funding for the study included grants from the U.S. National Institutes of Health, the Doris Duke Charitable Foundation, and the Massachusetts Life Sciences Center. The authors reported no competing interests relevant to the current study; additional disclosures are listed in the journal article. (massgeneralbrigham.org)
