Exercise may lower risk for cognitive decline
Editor's note: This article was updated in April 2022.
While sweating it out on the treadmill, you might think about the good it’s doing for your heart or waistline. But evidence is building that exercise could also be beneficial for the brain.
Recent studies have shown that exercise may reduce Alzheimer’s risk and possibly slow cognitive decline, but what type of exercise, exactly who can benefit, and why, are still largely unknown.
A study from the University of Wisconsin found people over 60 at high risk of Alzheimer’s who performed 30 minutes of moderate exercise five days a week had a lower risk of developing the disease and less memory and cognitive problems.
Another study from the University of Kansas found some participants with Alzheimer’s were able to increase their scores on memory tests after routinely exercising, and even increase the size of their brain’s hippocampus, an area of the brain important for learning and memory that is typically impacted early in the Alzheimer’s disease process.
To date, exercise studies have been too small-scale to be definitive or had mixed results regarding the impact on memory and brain function. But researchers have recently launched two rigorous, large-scale studies they hope will provide clearer answers on how exercise can reduce risk.
Major exercise studies underway
One promising investigation is the EXERT Study
funded by the National Institute on Aging, co-led by Laura Baker, Ph.D., associate professor at the Wake Forest School of Medicine. EXERT is one of the largest and most rigorous studies to date testing how two intensities of exercise can impact memory loss and cognitive decline in people already experiencing problems.
For the first 12 months of the EXERT Study, 300 participants exercise for 45 minutes, four days a week under the supervision of a trainer at their local YMCA. Half of the participants do moderately intense aerobic exercises, while the other half do stretching and balancing exercises. In the final six months of the study, participants are encouraged to exercise on their own — to measure if they can stick with the program. At various points in the study both groups are tested on their cognitive abilities.
“We are really not testing whether exercise works, we are testing what type of exercise works,” Baker says.
If the study shows positive results, one day people experiencing early signs of cognitive impairment could get a “prescription” for a specific program of exercise to help slow or prevent memory and other thinking problems, Baker says. Results of the EXERT Study are expected in summer 2022.
Baker is also serving as principal investigator on another study related to exercise called U.S. POINTER
. This two-year clinical trial evaluates whether lifestyle interventions that include exercise and simultaneously target multiple risk factors can protect cognitive function in more than 2,000 older adults at increased risk for cognitive decline. The study is the first of its kind in the U.S. and will examine how increased physical exercise, a healthier diet, mental and social stimulation and self-management of heart and vascular health impacts risk of cognitive decline.
Researchers are exploring how to prevent Alzheimer's. While prevention has no definitive answers, research has shown that we can take action to reduce our risk of developing it.
“This groundbreaking project is an unparalleled examination of how lifestyle ‘therapies’ that include more exercise may change our brain in ways that may protect against cognitive impairment, including Alzheimer’s disease and vascular dementia,” says Maria Carrillo, Ph.D., chief science officer of the Alzheimer’s Association and member of the U.S. POINTER Study Leadership team. “Depending on the results, lifestyle changes have the potential to be an effective strategy for reducing risk of cognitive decline.”
Why exercise helps
Current research suggests that sustained, moderate intensity aerobic exercise — such as brisk walking or swimming — offers the most benefit for the brain. While researchers don’t know exactly how exercise helps, many believe it has to do with increased flow of oxygen-rich blood to the brain and improved overall health of the blood vessels, which improves brain function.
“If we can’t get blood to the critical areas of the brain responsible for memory and other thinking abilities, those functions are not going to work,” Baker says. “Exercise helps clear out the pipes, and helps reduce the buildup of debris, like cholesterol, in our vessels.” Healthy blood vessels also strengthen the brain’s ability to fight or tolerate disease, Baker says.
In studies with rats, exercise was shown to increase the hormones that help develop new connections between nerve cells, which can improve communication between these cells. This improved communication likely benefits cognitive function.
Medicine with multiple benefits
If the EXERT and U.S. POINTER interventions prove effective, these studies could lead the way in the development of accessible and sustainable community-based programs for reducing risk and deterring dementia.
“We already know that exercise has benefits for cardiovascular disease, metabolic disease, depressed mood, and high stress. We are now studying the potential benefits of exercise for the brain. What other medication do you know of that has multiple benefits for the body and possibly the brain with no negative side effects?” Baker says. “We are looking at an intervention that tests whether exercise can be medicine for the brain for those people who are willing to give it a try.”
Maximize Exercise's Benefits
- It’s never too late: Studies show you can reap the benefits of exercise and potentially reduce your risk of dementia at any time in your life.
- Start small: Even walking briskly for 30 minutes a day has health benefits.
- Mix and match: Combine physical, social and mental activities to get the most benefit. For example, take a dance class and you’ll chat with your partner, memorize the steps and get your heart pumping.