If you need another reason to take the daily steps, science has handed it over to you.
New research shows that walking daily can reduce the risk of cognitive decline, especially among people with genetic predisposition to Alzheimer’s disease.
Approximately 3,000 participants between the ages of 70 and 79 reported on their daily walking habits over a decade, according to a survey published at the annual Alzheimer’s Disease Association International Conference. Those who reported maintaining or increasing walking habits over the years had significantly improved processing speed and executive functioning.
According to preprints that have not been peer-reviewed or published in professional journals, the benefits of walking were particularly prominent among people with genetic predisposition to developing Alzheimer’s disease.
“The kinesiology of the University of Calgary in Alberta,” said Dr. Cindy Balha, assistant professor of kinesiology at the University of Calgary in Alberta. “So I recommend reducing sedentary behavior by introducing small matches while you need to sit.”
Alzheimer’s disease is a severe form of dementia, which is thought to be caused by the accumulation of harmful plaques in the brain that prevents how nerve cells communicate, ultimately leading to their death, Barha said.
As more neurons die, people with Alzheimer’s disease can develop progressive memory loss, confusion, personality changes, and physical decline. Ultimately, the disease can be fatal and no known treatment is available.
Genetics is thought to play a major role in disease. Specifically, a genotype called APOE affects the metabolism of plaque and other fats throughout the bloodstream. Certain types of ApoE4 are known to make it difficult for the brain to clean plaque and are associated with a higher risk of cognitive decline.
About 15% to 25% of people carry this version of the APOE gene, according to data from the National Institutes of Health.
Mind and body connection
Although the new study did not test a uniform walking regimen, Barha suggests that multiple times daily walks and sedentary behaviors should be split up, and maintain consistent walking habits each year to prevent cognitive decline.
“It takes more research to determine the number of steps you actually need, but it definitely gets better than that,” she said. “The next step is actually trying to figure out the minimum walking amounts of women vs. men, APOE4 carrier vs. non-carrier in different subgroups (e.g.).”
A 2022 study found that even people who walked about 3,800 steps per day at any rate reduce their risk of dementia by 25%.
What is happening between the brain and the rest of the body? Experts have several theories.
One is like a brain fertilizer, as it has been shown to help the body produce more proteins called brain-derived neurotrophic factors or BDNF, which helps to grow more cells and form new connections.
“We believe that there are proteins that are released from muscles that migrate into the brain and that start a response that goes beyond the blood-brain barrier or blood-brain barrier and ultimately leads to an increase in BDNF in the brain,” she said.
Another theory is that exercise reduces neuroinflammation, a common symptom of Alzheimer’s disease.
The brain sends immune cells called microglia to attack plaque accumulation, which can backfire, explained Dr. Christian Lann, an associate professor of medicine at the Center for Cardiovascular Research at Massachusetts General Hospital and Harvard Medical School. Chronic inflammation can cause microglia to launch attacks on healthy brain cells, causing damage to brain connections.
“Exercise really strengthens the gene expression program that microglia need to function properly,” Ran said.
Researchers were surprised that walking provided the greatest benefits to people with the APOE4 gene compared to those without it. It will likely require more research to understand why this is, but Barha has a theory.
“I think before the research began, APOE4 careers had more room for cognitive growth, as they may already have experienced cognitive decline,” she said. “They also have room for improvement.”
The study itself also may motivate participants with the APOE4 gene to walk more than before, slowing down the rate of decline.
“This is a very powerful example (it) it’s never too late to start exercising,” Ran said. “Every step is important and it’s far better to do an exercise regimen you actually like. You can actually stick to it.”
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