While many studies have shown that greater amounts or longer durations of walking are associated with a lower risk of Alzheimer’s disease (AD) or cognitive decline in older adults, the neuropathological basis for this is not yet fully understood.

To examine the relationship between walking intensity and duration and longitudinal changes in Alzheimer’s disease (AD)-related brain pathologies, including Aβ and tau accumulation, neurodegeneration, and white matter hyperintensity (WMH).

Data were drawn from the Korean Brain Aging Study for the Early Diagnosis and Prediction of AD, a longitudinal cohort study (initiated in 2014).

Community and memory clinic setting.

One hundred fifty-one older adults.

Participants underwent baseline and 4-year follow-up neuroimaging assessments. Lifetime walking, as measured using the Lifetime Total Physical Activity Questionnaire, was categorized by intensity (high vs. low) and duration (short ≤360 min/week vs. long >360 min/week), forming four combined walking groups. Aβ and tau deposition, neurodegeneration, and WMH volume were assessed via PET/MRI.

Long-duration or high-intensity walking was associated with significantly reduced Aβ accumulation over 4 years. The high-combined walking group showed similar benefits, while medium-combined groups did not. The effect was significant only in the early life-initiated walking subgroup. No associations were found with tau, neurodegeneration, or WMH volume.

Long-duration, high-intensity walking may reduce brain Aβ accumulation, potentially lowering AD risk, particularly when initiated before late life.