Exercise and curiosity could help keep Alzheimer’s disease (search) and other degenerative brain diseases at bay.

“It’s really common sense that exercise and improved behaviors are going to be important,” says Sangram Sisodia, PhD, who worked on a new mouse study.

That means staying fit and taking “opportunities to learn, be inquisitive, and explore the world,” Sisodia tells WebMD.

“It appears that exercise and physical activity are very important for brain function,” agrees Karoly Mirnics, MD, assistant professor of psychiatry and neurobiology at the University of Pittsburgh.

In fact, activity could help avoid other brain diseases, too, says Mirnics, who also worked on the mouse study. “What we tapped into is not a very disease-specific process, but a universal process, I think,” he tells WebMD.

Just how big are the brain benefits of exercise and learning? Does physical and mental activity really hedge against Alzheimer’s disease?

Sisodia and Mirnics shared their views with WebMD. Their study’s results may point the way towards healthier brains for humans, too.

Exercise, Activity Not Cure-Alls

Exercise and activity have not been found to cure Alzheimer’s disease or any other brain condition, Mirnics stresses. But they’ve shown promise in halting the disease’s progression in experiments on animals.

“I think that’s pretty important news,” he says.

A lot of population-based studies support the idea, says Sisodia. “This pinpoints some very important issues,” he tells WebMD, adding that exercise can strengthen the brain, as well as the muscles.

Alzheimer’s Disease: Leading Cause of Dementia

An estimated 4.5 million people in the U.S. have Alzheimer’s disease. Most of them are senior citizens. Alzheimer’s disease affects one in 10 people over age 65 and nearly half of those older than 85, says the Alzheimer’s Association.

Currently, there is no cure for Alzheimer’s disease. However, medications can help manage some symptoms. The progressive disease damages areas of the brain involved in memory, intelligence, judgment, language, and behavior.

In Alzheimer’s disease, proteins called amyloid protein form tangles and plaques that clog the brain. Those tell-tale signs have been found in the brains of dead Alzheimer’s patients.

Mimicking Alzheimer’s Disease in Mice

The researchers tested mice with early stages of a brain disease similar to Alzheimer’s disease. They put nine male mice into an “enriched environment.” Picture a mouse’s deluxe suite, fully loaded with plenty of wheels to run on, toys to play with, and colorful tunnels to wiggle through.

Nine other male mice got “plain-Jane” accommodations. Their cage had no special features.

After five months, the two groups had important differences. The mice in the enriched environment had less Alzheimer’s-related amyloid protein in their brains. They also had 41 genes that had kicked into high gear to help guard against brain problems.

“Exercise was turning up the expression of the genes,” Sisodia tells WebMD. As for the other results, Sisodia says exercise may have prompted new blood vessels to help clear troublesome proteins out of the brain. “That needs to be tested, of course,” he says.

Ignoring a Golden Opportunity?

The mice in the enriched cage were watched during the study’s last month. Some took full advantage of their surroundings. They spent more than 40 percent of their time on the running wheel and tried everything the cage had to offer.

But other mice in the same setting weren’t very active. “They had every opportunity,” Sisodia tells WebMD. “It wasn’t like there were three or four mice to one treadmill. Some felt like it more than others.”

The most active mice had the healthiest brains at the end of the study. Apparently, the choice to stay idle or get moving had big consequences for the brains of the mice.

More Work Ahead

Does activity help later stages of Alzheimer’s disease? What kinds of activities are best? Those topics will get more scrutiny.

“We have to understand how much [activity] and which kinds,” Mirnics tells WebMD. For instance, he says there’s a big difference between running 5 miles and playing basketball three to five times weekly. “That’s a very different set of skills,” says Mirnics.

Meanwhile, many people could stand to be a little more active. Learn a language, do the crossword puzzle, take a walk… the possibilities are endless, even if no one knows which activities are most helpful.

All the more reason for young people to turn off the TV and get moving, says Sisodia. He says it’s “preposterous” for physical education classes to be cut back for kids and fears that in 20 to 40 years, the number of people with Alzheimer’s disease will be “much higher than expected.”

Alzheimer’s patients should talk with their doctors to “work out a plan that is beneficial for the whole body,” says Mirnics.

Their study appears in the March 11 edition of the journal Cell.

By Miranda Hitti, reviewed by Michael W. Smith, MD

SOURCES: Lazarov, O. Cell, March 11, 2005; vol 120: pp 701-713. Sangram Sisodia, PhD, professor of neurobiology, pharmacology, and physiology, University of Chicago. Karoly Mirnics, MD, assistant professor of psychiatry and neurobiology, University of Pittsburgh. Alzheimer’s Association, “Fact Sheet: About Alzheimer’s Disease Statistics.” WebMD Medical Reference From Healthwise: “Alzheimer’s Disease: Topic Overview.”