Overview
- Walking 3,000 to 5,000 steps per day was associated with about a three-year delay in cognitive decline, rising to roughly seven years at 5,000 to 7,500 steps.
- The association was concentrated in older adults with elevated brain amyloid-beta at baseline, with little change observed in those with low amyloid.
- Higher step counts were tied to slower tau buildup in the inferior temporal cortex rather than to changes in amyloid levels, and modeling suggested tau largely mediated the cognitive benefit.
- Benefits increased up to around 7,500 steps per day with minimal additional gain beyond that level, suggesting a practical target below the popular 10,000-step goal.
- The analysis followed 296 cognitively unimpaired adults for up to 14 years using pedometers and PET imaging, with authors noting observational limits and calling for randomized trials to test causality and mechanisms.