Physical activity benefits all aspects of the body, notably the brain. Recent studies indicate it can help decelerate the advancement of Alzheimer’s disease in individuals prone to this neurodegenerative disorder.
Previous research has also linked exercise to improved cognitive health, suggesting that more physically active individuals with Alzheimer’s might experience slower cognitive and memory deterioration. However, these earlier studies had limitations that the newest analysis has now resolved.
The most recent study, appearing in Nature Medicine, involved scientists employing a more objective method to assess physical activity in individuals at elevated Alzheimer’s risk. By tracking disease markers with advanced imaging, they demonstrated that more active participants lowered their cognitive decline risk by as much as 54%. Additionally, they observed a slowing of cognitive and functional decline starting at approximately 3,000 steps daily for those who were largely inactive.
The research involved nearly 300 individuals who maintained normal cognitive function but faced an elevated risk of Alzheimer’s, evidenced by brain scans showing amyloid plaques—the characteristic protein clusters of the disease. The buildup of amyloid plaques harms neurons crucial for higher-level thinking and memory, eventually prompting the accumulation of tau, another protein toxic to nerve cells. Dr. Wai-Ying Wendy Yau, a neurologist at Mass General Brigham, led the researchers who tracked this amyloid-to-tau transition as a marker of disease progression, averaging approximately nine years per participant.
“Our findings indicate that amyloid and physical activity appear to collaborate in influencing tau and cognitive decline,” Yau stated. “For individuals with significant amyloid levels in their brain, who are at increased risk for tau development and cognitive deterioration—yet remain asymptomatic—our study suggests that substantial physical activity could impede disease progression.”
Although participants’ amyloid levels remained largely stable throughout the study, their tau accumulation, a sign of Alzheimer’s advancement, varied based on their physical activity. This correlated with a slower rate of cognitive decline, as assessed by various cognitive and functional evaluations.
Participants who averaged the highest daily step counts, tracked via pedometer, experienced up to a 54% reduction in their cognitive decline rate compared to inactive individuals. The most active also exhibited comparable advantages in functional decline metrics, which assess abilities like dressing and performing everyday tasks. Among the most physically fit, this form of decline decelerated by up to 51% compared to their inactive counterparts.
“Amyloid serves as a method to determine if an individual is on the path toward Alzheimer’s disease,” explained Dr. Jasmeer Chhatwal, associate professor of neurology at Mass General Brigham and Harvard Medical School, and the study’s senior author. “However, even with the significant risk factor of amyloid presence, these findings indicate that physical activity can modify the relationship between amyloid and tau. This is a crucial element influencing cognitive performance, as tau appears strongly linked to cognitive abilities.”
The impact proved particularly pronounced among previously inactive individuals who began daily walking. Chhatwal finds this encouraging, as these individuals face the highest risk for rapid cognitive deterioration.
The study indicated that exercise benefits eventually plateau, with the deceleration of decline stabilizing after approximately 5,000 to 7,500 steps daily. Nevertheless, both he and Yau believe these results should reassure individuals that even modest physical activity can positively affect the brain, particularly for those with sedentary lifestyles.
Yau and Chhatwal emphasize that these findings do not position physical activity as a universal remedy for Alzheimer’s. Rather, the outcomes strongly suggest that exercise ought to be integrated into any preventative approach for individuals with existing brain amyloid who are not yet exhibiting disease symptoms. For instance, combining newer anti-amyloid medications with physical activity might defer Alzheimer’s progression. With advancements in detecting amyloid signs—currently through PET brain scans and increasingly via enhanced blood tests—more individuals will learn about their disease risk.
“These results empower individuals by demonstrating that a diagnosis of Alzheimer’s does not inevitably lead to rapid cognitive decline,” Chhatwal stated. “The findings underscore that lifestyle elements aren’t merely peripheral to major Alzheimer’s disease mechanisms; rather, they can significantly influence how amyloid contributes to cognitive decline.”