Media release

From: Springer Nature

Health: Moderate daily activity may slow Alzheimer’s disease-related decline

Taking over 5,000 steps per day may slow tau protein buildup and cognitive decline in people with preclinical Alzheimer’s disease, according to a 14-year study of cognitively unimpaired older adults, published in Nature Medicine. This is one of the first studies to explore the relationship between different levels of physical activity and key Alzheimer’s disease biomarkers, and suggests a more achievable exercise goal for older adults to help slow disease progression.

Physical inactivity is a well-established risk factor for Alzheimer’s disease, and safe and effective ways to slow disease progression are urgently needed. Animal studies suggest that exercise can reduce Alzheimer’s disease-related pathology, but the effects of physical activity on biomarkers of this disease and the dose–response relationship of this in humans remain unclear. So far, few studies have used objective measures of activity to assess the effects on amyloid and tau proteins — biomarkers of Alzheimer’s disease — and none have done so over a long-term timeframe.

Wai-Ying Wendy Yau, Jasmeer Chhatwal and colleagues analysed data from 294 cognitively unimpaired older adults (those 50–90 years of age) in the Harvard Aging Brain Study, including pedometer-measured physical activity, longitudinal amyloid and tau PET imaging, and annual cognitive assessments for up to 14 years. The authors found that higher physical activity was associated with slower amyloid-related cognitive decline, indicative of a potential protective effect of physical activity. They found that this benefit was associated with slowing of tau accumulation, rather than to changes in amyloid pathology. Tau accumulation and cognition plateaued at a moderate activity level of 5,001–7,500 steps per day. Encouragingly, even modest activity (3,001–5000 steps per day) was associated with notable slowing of tau accumulation and cognitive decline.

The findings suggest that increasing physical activity may help slow tau pathology and cognitive decline in people with preclinical Alzheimer’s disease. Moreover, with the widespread use of digital wearables, such as smart watches, this study highlights an accessible physical activity goal that could encourage greater engagement among older sedentary adults.