Even moderate amounts of walking may help protect brain function and slow changes linked to Alzheimer’s disease.
New research reveals a modest amount of daily movement may help protect the brain from Alzheimer’s disease, but the apparent benefit does not involve the biological target researchers expected.
Using pedometers, researchers followed nearly 300 older adults with early brain changes associated with Alzheimer’s for nine to 11 years. Physical activity was not associated with lower levels of amyloid plaques, the toxic deposits targeted by many current Alzheimer’s treatments.
Walking slowed a different disease marker
Among participants who already had amyloid plaques, however, greater physical activity was linked to slower accumulation of misfolded tau proteins in certain brain regions. Tau develops later in Alzheimer’s and is more closely associated with declining memory, thinking, and everyday function. More active participants experienced nearly half as much cognitive and functional decline.
The association appeared at about 3,000 steps a day, equal to roughly 30 minutes of moderate walking. Benefits were strongest between 5,000 and 7,500 daily steps, then leveled off. Walking beyond that range did not necessarily provide additional protection, suggesting that older adults with sedentary lifestyles may not need to reach the commonly promoted goal of 10,000 steps.
The findings have important limitations. The study included a relatively small sample of mostly white, highly educated adults in the United States and did not account for every health or lifestyle factor that might influence the results. Walking may also protect the brain through mechanisms not measured in the research. Even so, the findings add to broader evidence linking physical activity with a lower risk of dementia.
Modest activity repeatedly predicts lower risk
A UK study of 1,139 people over 50 found that those who were moderately to vigorously active had a 34-50% reduction in dementia risk when followed over eight to ten years. Among those who developed dementia, staying active reduced their memory decline, particularly in older women.
A larger 2022 UK study tracked 78,430 people for seven years using wrist accelerometers. It found a 25% reduction in dementia risk with just 3,800 steps daily, rising to 50% at 9,800 steps.
However, people who walked more also had better cardiovascular health – lower cholesterol, better sleep and blood pressure, and reduced diabetes risk. Since these heart and stroke risk factors also increase dementia risk, the picture is complex.
Healthy habits often go together. People who exercise are more likely to eat well, not smoke, look after their heart health, and have fewer financial stresses. This makes it hard to know which factor is having the biggest effect. The researchers tried to account for this, but because these habits are so closely linked, it’s difficult to say that exercise alone is responsible.
Exercise and heart health overlap
However, there is a strong case for this as there are multiple ways exercise might support the brain: improving cardiovascular health, increasing blood flow, and boosting chemicals that promote brain-cell connections.
One such substance is irisin, a hormone produced by muscles that acts on almost all faulty brain mechanisms associated with Alzheimer’s, including inflammation. This and other chemicals, such as BDNF, associated with exercise, provide plausible biological pathways for how physical activity might directly influence brain health beyond its cardiovascular benefits.
But the relationship might work in reverse, too. People may become less active because of early Alzheimer’s symptoms. Those with hearing problems, for instance – itself a dementia risk factor – often report barriers that make them stop being active before other dementia symptoms appear.
Reduced activity then accelerates memory decline. This creates a vicious circle. Early disease symptoms – such as not hearing – can affect self-esteem and reduce engagment in physical activity, which in turn worsens cognitive decline.
Achievable walks may still help
Brisk walking might be particularly beneficial. A small trial of 15 people with mild to moderate Alzheimer’s who did Nordic walking (an enhanced walking technique that uses poles to work your upper body as well as your legs) maintained brain function over 24 weeks, with some functions even improving.
The 15 who received only standard care showed decline or no improvement. Though small, the trial suggests that even people already diagnosed with Alzheimer’s might benefit from increased physical activity, including brisk walking.
Getting outside, particularly in nature, may be especially beneficial for preventing dementia – possibly because it improves mood and sleep while reducing isolation – all dementia risk factors. The combination of physical movement, natural light exposure, and social interaction when walking outdoors may create multiple protective effects that complement each other.
The challenge now is helping people overcome barriers to outdoor activity, such as safety concerns, fear of falling, or simply preferring the comfort of the sofa – particularly during wetter, colder months. But the evidence suggests that even a few minutes of walking could make a difference, and that modest, achievable targets – a half-hour stroll rather than a marathon training regime – may offer substantial protection against cognitive decline.
Reference: “Alzheimer’s decline slows with just a few thousand steps a day” by Mariana Lenharo,3 November 2025, Nature.
DOI: 10.1038/d41586-025-03596-2
Adapted from an article originally published in The Conversation.
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