Higher physical activity may slow cognitive and functional decline in older adults at risk for Alzheimer’s disease (AD) by reducing tau accumulation rather than amyloid burden. In a study of cognitively unimpaired older adults with pedometer-measured step counts, greater physical activity was linked to slower decline among those with elevated baseline amyloid. While activity levels were not associated with differences in amyloid burden at baseline or over time, they were related to slower amyloid-associated tau accumulation in the inferior temporal region, which significantly mediated the protective effect on cognition. Dose–response analyses revealed a curvilinear relationship, with benefits plateauing at a moderate activity level of 5,001–7,500 steps per day—an achievable target for sedentary individuals. These findings support targeting physical inactivity as a promising modifiable intervention to alter the trajectory of preclinical AD. Source: https://www.nature.com/
