Plenty of studies have shown that exercise is good for the aging brain, but a new scientific review provides the clearest evidence yet. Physical activity is associated with a reduced risk of Alzheimer’s disease, the paper concludes, and it may also improve the performance of daily activities for people who already have the disease.
But simply moving around every day isn’t enough, says lead author Kathleen Martin Ginis, professor of health and exercise science at the University of British Columbia in Canada. To really reap the benefits of exercise, studies show, older adults need to regularly push themselves to moderate-intensity levels.
The new review, published in the journal BMC Public Health, was conducted so experts could form a consensus as to whether physical activity guidelines for older adults—like those set by the World Health Organization and the Centers for Disease Control and Prevention—were helpful for cognitive health.
“The recommended activity dose is protective against 20 or so other chronic conditions,” says Martin Ginis, “but unfortunately there wasn’t enough evidence when those guidelines were made to show that exercise could reduce the risk of dementia.” Now there is, she says.
Martin Ginis and her colleagues reviewed data from more than 150 research articles—some of which examined the risk of developing Alzheimer’s disease, and some of which looked at quality of life for those who’d been diagnosed. Based on those articles, the panel concluded with great certainty that older adults who are physically active are significantly less likely to develop Alzheimer’s disease compared to people who are inactive.
“It’s really exciting to see that it’s pretty much watertight at this point,” says Martin Ginis. “And if we can get that message out there, there might be older adults who are motivated to exercise if they know this is one of the benefits.”
The research also showed that people who had Alzheimer’s disease but remained physically active were better able to get around and function on a daily basis, compared to Alzheimer’s patients who weren’t active. Physical activity may also improve general cognition and balance, Martin Ginis says, although these claims aren’t quite as solid. “General cognition is the big one people want to know about,” she says. “While we can’t yet say that the evidence is crystal clear, we can say that it’s promising.”
Experts still don’t know enough to give a specific “exercise prescription” for the prevention or treatment of Alzheimer’s disease, but Martin Ginis says that is her ultimate goal. For now, her best advice is for older adults to follow the current guidelines for people 65 and older. That means that older adults who are fit and healthy should get at least 150 minutes of moderate intensity aerobic activity (such as brisk walking) every week, and muscle-strengthening activities on two or more days. That moderate-intensity activity can be swapped for 75 minutes of vigorous activity (such as jogging or running), or a combination of the two.
The moderate- to vigorous intensity part is important, says Martin Ginis. “You can’t just go for a leisurely stroll,” she says. “You do have to be pushing it, getting a little out of breath so it’s challenging to talk to the person next to you.”
Martin Ginis notes that most of the studies looked at adults with early-stage Alzheimer’s, when it was still relatively easy for them to get out and walk or maintain a regular exercise routine. It can be challenging to encourage exercise in loved ones with dementia, she acknowledges, especially more advanced cases.
To help with these challenges, she and her colleagues developed a toolkit—available on the Ontario Brain Institute’s website—to help older adults stay safe and get the types of exercise they need. If someone has issues with mobility or balance, for example, they might still be able to get their heart rate up by doing chair aerobics. Any adults with physical health issues should check with their doctors before starting an exercise program, Martin Ginis says.
Alzheimer’s disease is the most common form of dementia, and the number of worldwide cases is expected to increase from 20.8 million in 2010 to 106 million in 2050. But Martin Ginis says this review can be good news for anyone who’s willing and motivated to act preemptively.