NIH-funded researchers are aiming to find out if a healthy dose of vigorous exercise might stall or prevent mild cognitive impairment from progressing to dementia.

The Alzheimer’s Association estimates that about one in five Americans age 65-plus suffers from a form of memory problem known as MCI, or mild cognitive impairment. About one third of those will go on to develop full-blown Alzheimer’s Disease or dementia within five years of being diagnosed with MCI.

Once MCI has progressed to AD, there’s little that can be done. Drug after drug has failed to stop or reverse Alzheimer’s, which now affects more than 5 million Americans, with the risk increasing with advancing age. The success rate for Alzheimer’s drugs is a depressing .5 percent. Even medicines that initially looked promising have flopped as research progressed.

We need a better strategy.

Treating MCI Before It Progresses to AD

If we can’t treat Alzheimer’s with meds once it’s been diagnosed, what can we do? One answer is to deal with MCI before it progresses—prevention rather than treatment—and Dr. Laura Baker, associate professor of internal medicine and neurology at Wake Forest School of Medicine, thinks she’s found a way. The ”medicine” she is studying is cheap and accessible.

Her medicine is exercise—not a casual stroll around the mall or light gardening, but heart-pumping, get-your-sweat on workouts.

In previous research, she and others have found that exercise can help people hang on to cognitive skills. Now Baker is co-chairing EXERT: Exercise in Adults with Mild Memory Problems, a National Institutes of Health backed clinical trial that focuses on exercise as a remedy for MCI. The trial launched in June 2016 and is still recruiting. In all, the research team will enroll 300 men and women ages 65 to 89 in 11 states, all with MCI and sedentary at the study’s start.

Why Exercise as a Remedy for MCI?

The EXERT study is based on previous research that suggests high-intensity exercise can help boost lagging cognitive abilities.

In one study, called PACE-2, 65 men and women who had both MCI and pre-diabetes (abnormally high blood sugar, but not yet diabetes) were randomly assigned to do high-intensity exercise or lower intensity stretching and balance exercises.

Both the high- and low-intensity groups exercised for the same amount and time—45 minutes, four days a week for six months. But the vigorous group worked out to about 70 or 80 percent of their maximum heart rate, while the lower intensity group only exercised at about half that rate.\

Results? People in the high-intensity group became better able to plan and organize than the lower-intensity group, but they weren’t better in tasks that challenge short-term memory. The researchers did find that blood flow increased in brain regions affected by Alzheimer’s—a good thing. And in this vigorous exercise group, levels of the protein known as tau, which is normally linked with cognitive decline, decreased in those age 70 and above. Baker says that trial may simply not have been long enough to show full results. The EXERT trial will continue for 18 months.

In another recent study, researchers tracked cognitive decline for over a year in more than 4,000 older adults. The study team looked at which activities made a difference in preventing a mental slide, says researcher Elizabeth Howard, a visiting scientist at the Institute for Aging Research at Hebrew SeniorLife in Boston and associate professor at Northeastern University. The team asked the men and women about their typical activities and tested their cognitive skills at the start of the study, and then again one year later.

Which activities helped to minimize or arrest cognitive decline? Besides reading and computer activity, it was physical activity. ”If they [typically] engaged in physical activity, in one year’s time there was no cognitive decline,” Howard says. Swimming, biking, hiking and walking won out here.

Why Exercise Might Stall Cognitive Decline

Baker ticks off a number of reasons why exercise might slow down or even prevent MCI’s progression to dementia or Alzheimer’s. “Exercise increases blood flow, not only below the neck but above it, too,” she says. “Adequate blood flow in the brain is critical to support brain function, as blood provides oxygen and fuel needed for brain cells to do their work.” Baker adds that the blood vessels in the brain are small in diameter, making them especially vulnerable to the effects of an unhealthy lifestyle—including sedentary behavior.

According to Baker, exercise is known to reverse some of the natural aging process and has been shown to increase brain volume. “If you are losing brain volume, your risk of dementia is very high,” she says. She’s focusing her research efforts on the intensity dose needed to improve memory and thinking abilities.

Howard speculates that the more intense the physical activity, the better the effect may be on the brain.

What’s Involved in the EXERT Clinical Trial

If you enroll in EXERT, you’ll be assigned to a low-intensity or high-intensity group. The high-intensity group will walk on a treadmill and take aerobic exercise classes so their heart rate pumps to 75 percent of capacity. The low-intensity group will work out at much lower intensity, doing stretching, balance and range-of motion exercises. The trial is partnering with the YMCA, which will host the exercise sessions, and EXERT participants get a free membership to the YMCA in their area.

Whichever group you’re assigned to, you’ll put in four 45-minute sessions a week, including a warm-up and cool-down. That means that even if you’re in the lower intensity group, you’ll be doing more than the 150 minutes a week of moderate intensity aerobic activity along with two muscle-strengthening sessions that’s recommended by the government for older adults.

For one year, you’ll have a personal trainer and a personalized exercise program; for the last six months of the study, you’ll exercise on your own.

To enroll, men and women must be between 65 and 89 years old and have a diagnosis of mild cognitive impairment. And you must have been ”generally sedentary,” Baker says. Those who are already physically fit, she says, may already be at peak brain function and exercise might not help them much.

Overcoming Barriers

Baker is well aware of the hurdles to her research, the main one being funding. “We can’t patent exercise,” she says, “so there’s no way for a company to make money. Drug companies have no interest at all in exercise.”

Even so, Baker’s team is pressing forward, testing exercise in the same vigorous way as pharmaceutical companies and other scientists test new drugs. “We have multiple sites, a coordinating center overseeing it and diversity in the population,” Baker says. “We’re trying to see in a large enough group whether exercise can be medicine.”

“I have every bit of confidence we will be able to demonstrate the truth—whatever the truth is.”

Interested in Joining the Trial?

The trial is taking place at 15 academic medical centers and YMCAs across the United States. You can learn more about enrolling by clicking here.

If you’d like to know more about what it’s like to join a clinical trial and what the benefits are for you—and for others—click here.