Alzheimer's Could Be Slowed by Fewer Than 9,000 Steps a Day, Shows Study Linking Exercise With the Disease

Scientists believe even moderate amounts of exercise can slow cognitive decline in people at risk of developing Alzheimer's disease.

A study published in the journal JAMA Neurology found a total of around 8,900 steps per day appeared to slow rates of cognitive decline and brain volume loss in people who were at high risk. The individuals were considered at risk because of the levels of amyloid beta—a protein thought to play a role in Alzheimer's— in their brain.

Dr. Jasmeer Chhatwal, Assistant Professor at Harvard Medical School and co-author of the research, told Newsweek: "These results suggest that very achievable levels of physical activity may be protective in those at high risk of cognitive decline and that this effect can be augmented further by lowering vascular risk." Vascular risk factors include high blood pressure, obesity, smoking, diabetes, he explained.

"These results underscore that there are likely to be factors that we can modify to reduce the risk of cognitive decline, even if there is already evidence of build-up of the amyloid protein," he said.

The authors of the paper studied 182 people who were healthy when the study launched. The participants were involved in the Harvard Aging Brain Study, and had their cognition measured annually, and their brain volume approximately every three years for a period of seven years. Researchers told the participants to wear a pedometer for 7 days when they were awake, so they could document how many steps they took.

Researchers used positron emission tomography (PET) imaging to scan the brains of the participants for the amyloid beta protein. Their heart disease risk was also calculated by noting factors including their sex, BMI, blood pressure, whether they had diabetes, and if they smoked.

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A stock image of a two men exercising. Researchers have investigated whether working out affects levels of a biomarker linked to Alzheimer's disease. Getty

Past studies involving animals and humans have suggested exercise can preserve gray matter in the brain and prevent the buildup of amyloid beta, and the tau protein also linked to Alzheimer's, the authors wrote.

"Many people may be able to achieve the levels of activity seen here without major changes to their schedules," said Chhatwal.

However he said the results are limited because the team only measured physical activity at the start of the study and for just a week. What's more, the pedometers did not measure the intensity or the type of physical activity in which participants engaged. "We plan to address these questions in future research," Chhatwal said.

Still, as there are currently no drugs that treat Alzheimer's disease, it is important to find other ways we can alter the course of the disease, he argued.

Dr. James Pickett, head of research at the charity Alzheimer's Society, told Newsweek: "This study adds to previous research showing that people who are more active have a slower reduction in their memory and thinking skills as they get older, lose fewer brain cells, and have less amyloid, a hallmark of Alzheimer's disease, in their brain.

"However, this can only show us that levels of physical activity are linked to brain measures—it doesn't tell us that increasing activity would reduce your risk of getting dementia. There are ongoing trials to see if increasing activity can prevent cognitive decline and dementia, and we eagerly await these results—prevention is key, which is why we're funding a variety of studies to better understand the different risk factors for dementia.

Dr. Jana Voigt, head of research at the charity Alzheimer's Research UK, told Newsweek: "This study only measured daily step counts over a week, so we don't know how physically active people were throughout their lives. Future studies using long-term physical activity data could shed more light on the link between physical activity and brain health.

"While research to find new treatments to slow or stop the diseases that cause dementia continues, it is also important that we understand ways to help people reduce their risk. Whether it's walking the dog, going for a swim or hitting the gym, the key to keeping physically active is to do things you enjoy and will stick to long-term."

She advised: "While there is no sure-fire way to stave off dementia, you can also support brain health by eating a healthy diet, only drinking within recommended limits, staying mentally active, keeping weight and cholesterol in check, and not smoking."