3,000 steps a day to slow Alzheimer's? What the study really shows
- Claim
- 3,000 STEPS VS ALZHEIMER'S?
- Catch
- A LINK, NOT PROOF
- Verdict
- WALK ANYWAY, NOT A CURE
A study in Nature Medicine from Mass General Brigham and Harvard Medical School followed 296 cognitively unimpaired adults aged 50 to 90 from the Harvard Aging Brain Study for an average of 9.3 years, measuring daily steps with pedometers and tracking brain changes with PET scans. In participants with elevated amyloid at baseline, higher step counts were associated with slower tau buildup and slower cognitive and functional decline, and modeling suggested most of the benefit ran through slower tau accumulation. The researchers estimated that 3,000 to 5,000 steps a day was linked to decline arriving about 3 years later on average, and 5,000 to 7,500 steps to about 7 years later, with benefits leveling off at higher counts. People with low amyloid showed little decline and no significant link to activity. The catch: this was an observational study, so it shows an association, not cause and effect. Early disease could reduce activity (reverse causation), active people may differ in other ways, and the sample was under 300 mostly white, well-educated Americans. The authors and outside experts say randomized trials are needed.
SOURCES
- Yau et al. (2025), "Physical activity as a modifiable risk factor in preclinical Alzheimer's disease," Nature Medicine. DOI: 10.1038/s41591-025-03955-6
- Harvard Gazette (November 2025), "Walking 3,000 to 5,000 steps a day may delay Alzheimer's"
- Science Media Centre, expert reaction to the study
For information only, not medical advice. If you're worried about memory changes, talk to a doctor.
