Running Away From Alzheimer's: Vigorous Exercise May Help

Thirty years ago, Alexandra Finger ventured out onto the roads of her suburban New York neighborhood for a run. "This was back before it was fashionable," she recalls. "Neighbors would peek out the door and say, 'What is she doing?' "

Finger was doing what she'd always felt the urge to do—stay active. Before she started jogging, she walked and played tennis. And in the three decades since she first laced up her sneakers, the Pearl River resident has kept right on going, completing nine marathons, winning age-group awards at local races and continuing, at age 71, to log 25 to 30 miles of running every week.

For the past 15 years, however, Finger's mother, Marianna Silenzi, has been moving in a far different direction—one all too familiar to those who have dealt with Alzheimer's disease or other forms of dementia. Once an alert, independent woman, Silenzi, 94, now lives in a nursing home, unable, Finger says, to take care of herself.

Is there anything people can do to prevent the Alzheimer's disease that afflicts Finger's mother and some 4.5 million older Americans? A growing body of evidence suggests there is, something Finger has done all along but that her mother didn't do: exercise.

Over the past year, several studies have found that regular, vigorous workouts may prevent or at least delay the onset of dementia and even the forgetfulness often associated with normal aging. "We're not ready to write an exercise prescription for Alzheimer's or dementia yet," says neurologist Carl Cotman, director of the Institute for Brain Aging and Dementia at the University of California, Irvine. "But the results are extremely exciting."

So far most experiments have only involved lab mice running on exercise wheels in their cages. Still, what's happened to those marathon mice is impressive: In a study published in the Journal of Neuroscience in April, Cotman and his colleagues found that active mice, genetically bred to develop Alzheimer's, were far less likely than their sedentary counterparts to develop plaque deposits in the brain—a common "marker" of Alzheimer's.

Another study published in the same journal in September found that running greatly stimulated neurogenesis—the production of new neurons, or brain cells—in older mice. The creation of new neurons correlates to faster learning and better retention, which in humans may help keep memory and other brain functions sharp. Henriette van Praag of the Salk Institute for Biological Studies in La Jolla, Calif., who led the study, says, "If you want to give a gift to an older adult, get a treadmill."

Others are less bullish. "It may turn out to be true, but there's still a lot of research to do," says David A. Bennett, M.D., director of the Alzheimer's Disease Center at Rush University Medical Center in Chicago. He adds, however, that you don't need to wait to start exercising. "There are many proven benefits of physical activity."

The idea that regular exercise can help your head as well as your heart and joints is, well, a no-brainer, according to fitness expert Walter Bortz, M.D., clinical associate professor of medicine at Stanford University in Palo Alto, Calif. "What's good for the knee is good for the neurons," he says.

"When you do biceps curls with weights in a gym, blood and oxygen go to the biceps muscle and it enlarges," he says. "Same with the brain when you run or walk or do other forms of aerobic exercise. You're getting more blood and oxygen to it."

This may explain the latest study in this area, one not with mice but with 1,500 humans ages 65 to 79. In a paper published in October, researchers from the Karolinska Institute in Sweden found that those who had engaged in robust physical activity at least twice a week since their youth or middle age had a 50 percent lower chance of developing dementia and a 60 percent lower risk of developing Alzheimer's than those who were sedentary.

Both the mice and the Swedish participants who reduced their odds for dementia engaged in aerobic exercise. That type of activity—whether it's running on an exercise wheel or it's jogging, dancing, fast walking, biking or climbing stairs—works the large muscle groups in the legs, arms and hips. It also raises the level of oxygen in the blood and increases the heart rate over a sustained period (of at least 20 minutes).

While more research is needed to learn precisely how exercise and maximized blood flow might protect brain function, the possibility that her longtime running habit may help her offset the disease that has claimed her mother's mind is encouraging news for Finger. "I certainly hope it proves to be true," she says. In the meantime, she's not hedging any bets. "Just in case, I'm going to run a couple extra miles this week."