Alzheimer’s disease is complex and scientists are still working to understand its causes. While risk likely reflects genetics, environmental factors and chance, new research suggests that hitting a modest daily step count as you age may help lower the risk of cognitive decline.
A study in Nature Medicine analysed data from 296 adults aged 50 to 90, which tracks brain changes in older adults. All participants had healthy cognition at the start.
Researchers used PET scans to measure amyloid-beta plaques and tau tangles—hallmarks of Alzheimer’s. They also tracked physical activity with waistband pedometers and assessed cognition an average of 9.3 years later.
People with higher step counts had slower cognitive decline. Activity appeared to influence tau build-up: among those with elevated amyloid-beta at baseline, higher step counts were linked to a slower rise in tau.
Walking 3,000 to 5,000 steps a day was associated with a slower progression of Alzheimer’s in people at higher risk. The effect was meaningful: at-risk adults who walked 3,000 to 5,000 steps daily saw cognitive decline delayed by about three years.
Those logging 5,000 to 7,500 steps daily saw delays of about seven years. By contrast, sedentary participants had faster tau accumulation and more rapid declines in cognition and day-to-day function.
Doctors explain what may be driving the link and how to put it into practice.
Why might 3,000+ steps a day lower your risk of Alzheimer’s disease?
Several mechanisms are likely at play. The strongest signal in the study was the link between cognitive decline and tau build-up in the brain, says cognitive neurologist Dr Wai-Ying Wendy Yau. Exercise appears to counter that process.
“Exercise tends to bring down inflammation and inflammation is an important part of Alzheimer’s disease progress and process,” Dr Yau says. “By decreasing inflammation, it could have an impact on how tau chemically changes and then tends to aggregate and clump together to form these deposits.”
Movement also supports heart and vessel health, notes cardiologist Dr Evan Brittain. “Regular walking improves blood flow, reduces inflammation and enhances metabolic health, all of which support brain function,” he says.
Physical activity may further promote neuroplasticity—the brain’s ability to adapt and reorganise—“which could slow the build-up of harmful proteins central to Alzheimer’s pathology,” Dr Brittain says.
While exercise as brain protection is well known, the specific finding that 3,000+ steps may relate to slower tau build-up is new, adds neurologist Dr Clifford Segil. “This is a novel idea,” he says. “How walking can impact an ageing brain protein needs to be evaluated.”
Can other forms of exercise help, too?
While this study focused on step count, Dr Yau says other exercise is likely beneficial. “The beauty of using a pedometer is that it’s easy to understand and accessible,” she says. “The limitation is that we’re not capturing some of these other non-step forms of exercise.”
Dr Brittain agrees. “The key factor is sustained movement that raises heart rate and engages large muscle groups,” he says. “Cycling, swimming or even brisk household activity could all confer similar benefits.”
More movement is better
Dr Yau notes the benefit on tau build-up appeared to plateau after 7,500 steps a day and more research is needed to understand why.
Still, “more exercise is likely better,” Dr Brittain says. Activity as we age also supports heart and brain health, Dr Segil adds. “Weight-bearing exercises maintain bone density, lubricate our joints and maintain muscle mass as we age,” he says. “Cardiovascular exercises maintain our hearts and increase blood flow to our brains.”
Most encouraging, says Dr Brittain, is that even 3,000 to 5,000 steps a day seems to matter for brain health.
Other ways to lower your Alzheimer’s disease risk
Researchers are still uncovering why some people develop Alzheimer’s disease while others do not, but there are practical steps that may lower risk.
“There has been enough evidence so far that exercise is beneficial for health in general, including brain health and cognitive health,” says Dr Yau. “We’re highlighting that exercise can affect tau [accumulation]. We hope this provides extra motivation to some people.”
Consistency matters, adds Dr Brittain. “Daily movement, even light walking, can improve both heart and brain health. You don’t need a perfect routine. What matters is making physical activity a regular part of your life.”
General prevention advice from public health guidance includes preventing and managing diabetes, managing blood pressure, addressing hearing loss and limiting or avoiding alcohol and smoking.
Dr Yau also stresses you don’t need to become a marathoner to make a difference. “We’re seeing a difference in our participants with even slightly more activity a day,” she says. “Even a little bit helps.”
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