BOSTON, MASSACHUSETTS: Walking around 3,000 to 7,500 steps daily may be associated with slower cognitive decline in older adults with elevated amyloid-beta levels, according to a 2025 study published in Nature Medicine.
Researchers found that moderate physical activity was associated with slower accumulation of tau protein, a hallmark of Alzheimer’s-related brain changes. However, the findings do not prove that walking prevents Alzheimer’s disease or guarantee the same benefits for everyone.
What the Study Found
The study, titled Physical Activity as a Modifiable Risk Factor in Preclinical Alzheimer’s Disease, examined 296 adults aged 50 to 90 who had no significant cognitive impairment when the study began. Researchers from the Harvard Aging Brain Study followed participants for up to 14 years, measuring daily steps and tracking changes in cognition and brain health.
Participants wore pedometers to record their daily step counts. Researchers also conducted annual cognitive assessments and used brain imaging to monitor amyloid-beta and tau protein levels in subsets of participants.
The findings showed that higher physical activity was associated with slower cognitive and functional decline among people who had elevated amyloid-beta levels at baseline. (Yau et al., 2025)
How Daily Steps Compare
Researchers grouped participants according to their average daily step counts. Those taking 3,000 steps or fewer formed the least active reference group.
The analysis suggested the following pattern among participants with elevated amyloid-beta levels:
- 3,001 to 5,000 steps daily: Statistical models estimated approximately three years of delay in cognitive decline compared with the least active group.
- 5,001 to 7,500 steps daily: The estimated delay increased to approximately seven years.
- More than 7,500 steps daily: Researchers found no clear additional benefit compared with the 5,001 to 7,500-step group.
These figures represent estimates derived from statistical models of cognitive trajectories. They do not mean that walking a particular number of steps will pause Alzheimer’s disease for three or seven years in an individual.
The findings were also covered by HuffPost, which highlighted the potential significance of more achievable daily step counts for older adults.
A key distinction is that the study did not establish 3,000 steps as a proven protective threshold. Its low-activity category began at 3,001 steps, while participants taking 3,000 steps or fewer served as the reference group.
Why Tau Proteins Matter
Alzheimer’s disease involves several changes in the brain, including the accumulation of amyloid-beta plaques and abnormal tau proteins.
Amyloid-beta can accumulate between nerve cells, while abnormal tau can form tangles inside them. These changes are associated with damage to brain cells and the progression of cognitive symptoms.
In the study, greater physical activity was associated with slower accumulation of tau in the inferior temporal cortex, a brain region involved in memory and cognition. This relationship helped explain the association between physical activity and slower cognitive decline in participants with elevated amyloid-beta levels.
Researchers did not find that greater activity reduced amyloid-beta accumulation. Instead, the findings suggested that slower tau accumulation was an important factor linking physical activity with more favorable cognitive outcomes.
This distinction matters because it points to a possible relationship between movement and the progression of early Alzheimer’s-related brain changes, rather than showing that walking removes amyloid plaques or prevents the disease.
What the Study Cannot Prove
The findings are promising, but the research has limitations.
First, the study was observational. Researchers tracked participants’ activity and health outcomes rather than randomly assigning them to different exercise programs. The results therefore show an association, not proof that walking directly caused slower cognitive decline.
Second, the participants were predominantly highly educated and non-Hispanic White. The results may not apply equally to all populations.
Third, researchers measured physical activity at baseline. Pedometers did not capture the full history of participants’ exercise habits, walking speed, exercise intensity or changes in activity throughout the follow-up period. Activities that do not necessarily increase step counts, such as swimming and resistance training, were also not fully represented.
The study further focused on people who had no significant cognitive impairment at baseline. Its findings should not automatically be extended to people with diagnosed Alzheimer’s disease or other forms of dementia.
The researchers concluded that randomized clinical trials are needed to determine whether increasing physical activity can directly influence the progression of early Alzheimer’s disease.
How Older Adults Can Stay Active
Although the study does not establish a guaranteed step target for Alzheimer’s prevention, regular physical activity remains an important part of healthy ageing.
Older adults who currently walk very little can begin with short, comfortable walks and gradually increase their activity. Breaking walks into shorter sessions throughout the day can make a routine easier to maintain.
People with balance difficulties, joint pain or chronic health conditions should adapt their activities to their abilities. A healthcare professional can help identify appropriate exercise options and precautions when needed.
The World Health Organization recommends that adults aged 65 and older aim for at least 150 minutes of moderate-intensity aerobic activity each week, or an equivalent combination of moderate and vigorous activity.
It also recommends muscle-strengthening activities on at least two days a week and balance-focused activities for older adults with mobility difficulties.
These recommendations support overall health and mobility; they are not a specific prescription for preventing Alzheimer’s disease. (World Health Organization)
The US National Institute on Aging also emphasizes that evidence is not yet sufficient to conclude that exercise prevents Alzheimer’s disease. Nevertheless, physical activity remains one of several lifestyle factors researchers are investigating for its potential role in supporting cognitive health. (National Institute on Aging)
Conclusion
The 2025 Nature Medicine study found that moderate daily step counts were associated with slower tau accumulation and cognitive decline among older adults with elevated amyloid-beta levels. The researchers observed the strongest incremental differences when activity increased from very low levels to approximately 5,000 to 7,500 steps daily.
However, the study does not prove that walking 3,000 steps a day prevents Alzheimer’s disease, and its estimated delays cannot be guaranteed for individuals. Further research is needed to confirm whether increasing physical activity directly changes the progression of the disease.
For older adults, the practical message is to build a consistent and safe activity routine suited to their fitness and mobility. Walking can contribute to a healthier lifestyle without the pressure to reach 10,000 steps every day.
