Walking a little every day can slow Alzheimer’s disease
Physical activity is good for every part of your body, including your brain. The latest research shows that it can help slow the progression of Alzheimer’s disease in people who are at high risk of developing the neurodegenerative condition.
Other recent studies have linked exercise to better cognitive health, and these findings suggest that people with Alzheimer’s disease who are more physically active may be able to slow cognitive decline and memory problems. But these studies are limited by a number of factors addressed in the latest analysis.
In the current He studiespublished in Natural medicineScientists used a more objective method to measure physical activity among people at highest risk of developing Alzheimer’s disease and tracked signs of the disease using advanced imaging techniques to show that those who were more active had a reduced risk of cognitive decline by up to 54%. They also observed slower cognitive and functional decline starting at about 3,000 steps per day for people who were relatively sedentary.
The study included nearly 300 people who were still cognitively normal but at increased risk of developing Alzheimer’s disease because scans of their brains showed evidence of amyloid plaques, clumps of protein that are the hallmark of Alzheimer’s disease. When amyloid plaques build up, they begin to damage neurons involved in higher order thinking and memory and eventually lead to the buildup of another protein, tau, which is toxic to neurons. In this study, the researchers, led by Dr. Wei Ying and Wendy Yao, a neurologist at Mass General Brigham Hospital, tracked the transition from amyloid to tau as an indicator of disease progression for an average of nine years for the participants.
“What we show is that amyloid and physical activity appear to work together to influence tau and cognitive decline,” Yao says. “In people who have high levels of amyloid in their brains and are more susceptible to tau and cognitive decline – but who remain asymptomatic – our study shows that high levels of physical activity may be able to slow the progression of the disease.”
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While the subjects’ amyloid levels did not change significantly over the study period, tau accumulation, an indicator of Alzheimer’s disease progression, differed depending on how physically active the subjects were. This translated into slower cognitive decline according to a number of cognitive and functional tests.
Those who logged the highest number of steps on average per day, as measured by a pedometer, had their rate of cognitive decline reduced by up to 54% compared to those who were inactive. Those who were more active also saw similar benefits on measures of functional decline, which focus more on tasks such as the ability to get dressed and take care of daily activities. In fitter people, this type of decline was slowed by up to 51% compared to inactive people.
“Amyloid is a way to assess whether someone is on the path to Alzheimer’s disease,” says Dr. Jasmir Chhatwal, associate professor of neuroscience at UMass Brigham and Harvard Medical School and senior author of the study. “But even with the significant risk factor of having amyloid, these results suggest that physical activity can modify the relationship between amyloid and tau. This is an important part that impacts cognitive performance because tau appears to be closely linked to cognitive performance.”
Read more: The amazing power of a 10-minute walk
The effect was particularly strong among those who were inactive and started walking daily. This is encouraging, Chhatwal says, because these are the people most at risk for rapid cognitive decline.
The study showed that the benefits of exercise reached a plateau, so after about 5,000 to 7,500 steps per day, the decline plateaued. However, he and Yao say the findings should encourage people that even relatively small amounts of activity can benefit the brain, especially for those who don’t exercise.
Yao and Chatwal stress that the results do not indicate that physical activity is a cure-all for Alzheimer’s disease. Instead, the findings make a strong case that exercise should be part of any prevention strategy for people who already have amyloid in the brain but are not yet showing symptoms of the disease. For example, combining newer anti-amyloid medications with physical activity could be a way to prevent the development of Alzheimer’s disease. With advances in detecting signs of amyloid – now through positron tomography (PET) brain scans and with increasingly improved blood tests – more people will realize that they are at risk of developing the disease.
“These findings empower people and let them know that there is no inevitable relationship between a diagnosis of Alzheimer’s disease and rapid cognitive decline,” Chhatwal says. “These findings reinforce that lifestyle factors do not necessarily operate only around the edges of larger Alzheimer’s disease processes, but can have a profound impact on how amyloid causes cognitive decline.”