Modest walking linked to slower cognitive decline and lower tau

Researchers who followed nearly 300 older adults for up to 14 years report that modest daily walking was associated with slower cognitive decline and reduced accumulation of tau, a protein linked to Alzheimer’s disease progression. The analysis of participants in the Harvard Aging Brain Study, published in Nature Medicine, found benefits beginning at about 3,000 steps per day and a leveling off around 5,000 to 7,500 steps.

The team analyzed data from 294 to 296 volunteers aged 50 to 90 who were cognitively unimpaired at enrollment. Participants wore pedometers for a one-week period at baseline, underwent periodic positron emission tomography brain scans to measure beta-amyloid and tau proteins, and completed annual cognitive assessments for a median of about nine years and as long as 14. Researchers grouped participants by activity level: inactive (fewer than 3,000 steps), low (3,001 to 5,000), moderate (5,001 to 7,500), and high (7,501 and up).

Among people who began the study with elevated brain beta-amyloid—a biological marker associated with higher Alzheimer’s risk—those with low to moderate activity experienced substantially slower progression. Compared with inactive...