November is Alzheimer’s Awareness Month, and I thought I would share something I learned recently that relates to the effect of physical activity on the progression of Alzheimer’s disease.

Scientists say that Alzheimer’s develops when the neurons in our brain, which are the cells responsible for sending electrical and chemical messages throughout the body, become compromised by beta amyloid and tau proteins. Beta-amyloid forms plaques outside the neurons and tau forms tangles inside the neurons. As the neurons degenerate it gradually causes a loss of function.

In the Harvard Aging Brain Study, researchers are focused on identifying the early changes in the brain that signal the transition from normal cognition to cognitive decline, and to understand how and when these changes begin to affect memory and cognitive function. It’s a long-term study that follows a group of people age 50-90 and Harvard is collaborating with many other researchers as well, sharing data and research results.

In a recent collaboration, a group of researchers examined the cohort (people enrolled in the study) to determine if physical activity affected the progression of the disease. What they found was that physical activity, measured by the number of steps taken in a day by study participants, was effective in delaying cognitive decline. In other words, the plaques and tangles formed more slowly in people who were taking more steps.

Cognitive decline was delayed by three years on average for people who walked just 3,000-5,000 steps per day, and by seven years in people who walked 5,000-7,500 steps per day. Individuals who were sedentary, defined as sitting, reclining, or lying down for more than 10 hours a day, had a significantly faster buildup of tau proteins in the brain and more rapid declines in cognition and daily functioning.

Looking ahead, the researchers plan to look closer at which aspects of physical activity may be most important. For example, do exercise intensity and activity patterns make a difference? They also plan to examine more closely the mechanism that links physical activity, tau build-up, and cognitive decline.

For now, it’s safe to say that being less sedentary and increasing our physical activity is important for preserving brain health. As one of the lead researchers commented, “Every step counts – and even small increases in daily activities can build over time to create sustained changes in habit and health.”

Sherry DeWalt is the healthy lifestyles coordinator for the CGH Health Foundation in Sterling.