Modest Walking Slows Decline in Amyloid-Positive Adults

A Nature Medicine study of 296 cognitively unimpaired adults followed for up to 14 years found that modest daily walking—about 3,000–5,000 steps and especially 5,000–7,500 steps—was associated with substantially slower cognitive and functional decline, particularly among participants with elevated brain amyloid. Dose–response analyses showed previously sedentary individuals gained the most, with average delays in decline of roughly three years at 3,000–5,000 steps and about seven years at 5,000–7,500 steps, with benefits plateauing around 5,000–7,500 steps. The researchers report the association appears to work by slowing early neocortical accumulation and spread of tau protein—more closely linked to symptoms—rather than by lowering amyloid, and suggest effects could also involve reduced inflammation or improved blood flow. The study used wearable step counters, annual cognitive testing and PET imaging but is observational and relatively small, so it cannot prove causation. Authors and commentators call for randomized prevention trials and the authors specifically propose testing activity-based interventions alone or in combination with anti-amyloid therapies.