Emerging research suggests that walking as few as 3,000 steps a day could significantly slow cognitive decline associated with Alzheimer’s disease. While the precise mechanisms behind this effect remain unclear, scientists believe it may be linked to the benefits of regular physical activity on brain health, such as reducing inflammation or improving blood flow.
Previous studies have shown a correlation between exercise and reduced cognitive decline, but many relied on participants recalling their activity levels and rarely explored why staying active might have this impact. To address these gaps, researchers led by Wai-Ying Wendy Yau at Harvard University analysed data from 296 cognitively healthy individuals aged between 50 and 90. Each participant wore a step-tracking device for one week to provide an objective measure of daily activity.
Most participants also underwent brain imaging to assess baseline levels of misfolded proteins known as tau and beta-amyloid, which form clumps thought to trigger Alzheimer’s disease. These levels were monitored every two to three years over a follow-up period ranging from three to 14 years. Annual cognitive tests measured memory and processing speed. By combining step counts, brain imaging and cognitive performance data in a statistical model, the team estimated how physical activity influences cognitive decline.
The findings were striking. Among participants with above-average beta-amyloid levels at the outset, walking between 3,000 and 5,000 steps per day appeared to substantially slow the accumulation of tau protein, which is more strongly associated with Alzheimer’s symptoms than beta-amyloid. This reduction in tau build-up was linked to a 40 per cent slower rate of cognitive decline over an average nine-year follow-up compared with those who walked fewer than 3,000 steps daily.
Walking between 5,000 and 7,500 steps per day provided even greater benefits, slowing tau accumulation further and reducing cognitive decline by 54 per cent compared with inactive individuals. However, walking more than 7,500 steps did not appear to confer additional advantages, suggesting that the benefits plateau beyond a certain point.
Although the study did not investigate the exact biological processes involved, researchers speculate that exercise may reduce inflammation caused by misfolded proteins, improve blood flow to the brain, or increase levels of protective hormones. Despite these promising results, the study does not conclusively prove that walking 5,000 steps a day prevents or delays cognitive decline. Factors such as undiagnosed impairments, motivation, and socioeconomic conditions could also influence both activity levels and tau accumulation.
Nevertheless, regular exercise remains one of the most accessible and low-risk strategies for supporting overall health. Experts advise focusing less on achieving a specific step count and more on maintaining consistent physical activity. Even modest, regular movement can make a meaningful difference.
Further research, including randomised trials assigning participants to different step goals, is needed to confirm whether walking truly slows tau accumulation and cognitive decline. For now, the evidence reinforces a simple message: incorporating daily walking into your routine could be a powerful tool for promoting brain health as we age.
Link
https://www.newscientist.com/article/2501185-our-bodies-are-ageing-faster-than-ever-can-we-hit-the-brakes/
