Daily Steps Linked to Slower Alzheimer’s Progression, Study Finds

A recent observational study indicates that increasing daily physical activity may slow cognitive decline in older adults who show early signs of Alzheimer’s disease. The research, published in March 2023 in the journal Nature Medicine, suggests that walking between 3,000 and 7,500 steps daily can lead to a significant delay in cognitive deterioration.

The presence of beta amyloid and tau proteins are key indicators of Alzheimer’s disease. Beta amyloid can accumulate in the brain as early as an individual’s 30s, potentially disrupting communication among neurons. As these amyloid deposits increase, they can trigger the spread of tau proteins, which form tangles within brain cells, ultimately leading to cell death.

Dr. Wai-Ying Wendy Yau, a neurologist and memory disorders physician scientist at Massachusetts General Hospital in Boston, emphasized that physical activity may help slow the buildup of tau, which is closely linked to memory loss. According to Yau, individuals walking 3,000 to 5,000 steps daily experienced a cognitive decline delay of approximately three years, while those who walked 5,000 to 7,500 steps per day could see a delay of up to seven years.

While the findings are promising, some experts caution against oversimplifying the relationship between step counts and Alzheimer’s prevention. Dr. Richard Isaacson, director of research at the Institute for Neurodegenerative Diseases in Florida, noted that factors such as excessive body fat, prediabetes, and high blood pressure must also be considered. Isaacson stated, “Everyone needs their own individualized plan,” highlighting that merely walking a certain number of steps may not be sufficient for everyone.

Study Details and Findings

The study involved 296 participants aged between 50 and 90, using objective measures to enhance the reliability of its findings over a 14-year period. Participants’ steps were monitored using pedometers, and they underwent annual cognitive testing for an average of nine years. Initial PET (positron-emission tomography) scans measured levels of amyloid and tau, with a smaller group receiving follow-up scans at the study’s conclusion.

Results indicated that sedentary individuals experienced a significantly faster accumulation of tau proteins and a more rapid decline in cognition and daily functioning. Interestingly, the study revealed no significant relationship between physical activity and a decrease in beta amyloid levels, which typically precedes tau accumulation. Yau explained, “For a given amount of elevated amyloid burden, higher step counts were associated with slower accumulation of tau, which largely explained the relationship with slower cognitive decline.”

Implications for Future Research

Despite its observational nature, the study adds weight to existing knowledge linking heart health to brain health. Regular activities such as walking, reducing stress, ensuring quality sleep, and consuming a plant-based diet have long been recognized as beneficial for cognitive function. Isaacson remarked on the insights gained from previous animal studies, stating, “We’ve known for years that mice which exercise on their little wheels have about 50% less amyloid in their brains.”

As researchers continue to explore the connection between exercise and cognitive health, Yau reaffirmed the need for further investigation in humans. “While we need more research in people, I’m convinced exercise on a regular basis reduces amyloid buildup and improves cognition,” she concluded.

This study underscores the importance of physical activity for older adults, particularly those at risk for Alzheimer’s disease, highlighting the potential of simple lifestyle changes in delaying the progression of cognitive decline.