A new long-term observational study suggests that increasing your daily step count could help slow cognitive decline in older adults already showing biological markers of early Alzheimer’s disease.The buildup of beta amyloid and tau proteins is considered a defining feature of Alzheimer’s. Amyloid can start collecting between brain cells as early as a person’s 30s, interrupting communication within the brain. As these deposits grow, they can trigger the spread of abnormal tau proteins, which form tangles inside neurons and eventually destroy them.“Regular physical activity may slow the buildup of tau, which is the protein most strongly linked to memory loss, and delay mental decline in those in the early stages of Alzheimer’s,” said Dr. Wai-Ying Wendy Yau, a neurologist and memory disorders specialist at Massachusetts General Hospital in Boston.Daily Steps May Slow Alzheimer’s Progression, New Study SuggestsAlthough many people aim for 10,000 steps a day as a standard fitness goal, researchers found that walking as few as 3,000 steps daily appeared to delay brain changes associated with Alzheimer’s.The 14-year study found that cognitive decline was delayed by about three years among participants who took 3,000 to 5,000 steps a day, and by nearly seven years in those who reached 5,000 to 7,000 steps daily.“We want older adults who may be at risk of Alzheimer’s to consider small, manageable increases in their activity levels,” said Dr. Yau, who also works with Mass General Brigham Hospital in Boston. “Consistent habits, even mild ones, can support brain and cognitive health over time.”How Does Walking Affect the Brain?Globally, dementia affects about 50 million people, with Alzheimer’s being the most common cause. In the UK alone, over 500,000 people are estimated to have the disease. The condition is driven by toxic accumulations of amyloid-beta plaques and tau tangles in the brain.For the study, Yau and her colleagues analyzed data from 296 adults aged 50 to 90 who were cognitively healthy when the research began. Their data included annual cognitive assessments, pedometer-based step counts, and PET scans that measured amyloid and tau levels.Participants with low amyloid at baseline showed minimal cognitive decline or tau buildup over the years. However, those with higher amyloid levels faced greater risk, and in this group, walking more steps was associated with slower cognitive decline and reduced tau buildup. In contrast, sedentary participants experienced faster tau accumulation and mental decline, according to findings published in *Nature Medicine*.Why Exercise Might Protect the BrainWhile researchers caution that the study cannot completely rule out reverse causation, where early Alzheimer’s changes may cause reduced physical activity, the data still suggest a protective role for movement.“We need randomized clinical trials to confirm cause and effect, but it’s promising that exercise may help alter the course of the disease,” said Dr. Yau. “Even among people with amyloid buildup, higher activity levels could mean a slower rate of decline.”The exact mechanism remains uncertain, but scientists believe exercise improves blood circulation, reduces inflammation, and boosts hormones and growth factors that protect brain cells. “That’s the million-dollar question we hope to explore in future studies,” Yau added.A Simple Habit With Major PotentialDr. Julia Dudley of Alzheimer’s Research UK said the results highlight the impact of small, consistent activity. “The findings show that even a modest amount of walking, roughly 5,000 steps a day, is linked with slower accumulation of tau in the brain, one of the main drivers of Alzheimer’s,” she said.“This gives us a clearer understanding of how everyday movement can influence brain health and affect the root causes of the disease. More research, especially clinical trials, is needed to confirm how physical activity can prevent or slow dementia. But studies like this underline that simple, consistent lifestyle choices may help keep our minds healthier for longer.”
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