Increasing your daily step count could slow the progression of Alzheimer’s disease, especially in people already at high risk.
That’s the finding of a new study published in Nature Medicine by researchers at Mass General Brigham.
The team found that older adults with elevated levels of beta-amyloid – a protein linked to Alzheimer’s – experienced significantly slower cognitive decline if they were physically active.
Those who walked between 3,000 and 5,000 steps per day delayed symptoms by an average of three years, while those who walked 5,000 to 7,500 steps per day saw a delay of around seven years.
In contrast, sedentary participants showed a faster build-up of tau proteins in the brain – another key marker of Alzheimer’s – along with a more rapid loss of cognitive function and everyday abilities.
‘This helps explain why some people on the Alzheimer’s trajectory don’t deteriorate as quickly as others,’ said Dr Jasmeer Chhatwal, lead author of the study and neurologist at Mass General Brigham.
‘Lifestyle factors seem to influence the early stages of Alzheimer’s, which suggests we may be able to delay symptoms if we act early.’
A long-term look at movement and memory
The study followed 296 adults aged 50 to 90 from the Harvard Aging Brain Study, none of whom had cognitive impairments at the start.
Participants wore waist-mounted pedometers to track activity, and underwent PET brain scans to assess beta-amyloid and tau levels. Cognitive tests were carried out annually over a period ranging from two to 14 years (average of 9.3 years).
Among participants with high beta-amyloid levels, those who walked more had slower cognitive decline and less tau build-up over time. The researchers’ statistical models suggest that the main protective effect of physical activity came from its impact on reducing tau accumulation.
In contrast, those with low beta-amyloid levels showed minimal tau build-up or cognitive decline – and physical activity didn’t make a measurable difference.
‘These findings show it’s possible to build cognitive resilience and slow Alzheimer’s-related changes in the brain, even before symptoms appear,’ said Dr Reisa Sperling, neurologist and senior author of the study.
‘That’s incredibly promising in the fight to prevent dementia.’
Researchers plan to dig deeper into what types of physical activity are most beneficial, whether it’s intensity, consistency, or specific patterns of movement that matter most.
They also aim to better understand the biological link between physical exercise, tau protein, and brain health.
