Alzheimer's Disease Booming Among American Baby Boomers

Mar. 18, 2007— -- Every 71 seconds in this country, someone is diagnosed with Alzheimer's disease, and a startling new report out today from the Alzheimer's Association predicts that one out of every eight baby boomers — or almost 10 million Americans — is expected to develop the disease. If new treatments are years away, is there anything you can do today that might prevent it?

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Fran Hershkowitz's mother began losing her memory more than a decade ago, and now Fran, who is 63, worries if she might be next.

"It's frightening, too, to think that one day this is going to be me." the younger Hershkowitz said.

Evidence shows that physical exercise may be the most effective remedy to prevent Alzheimer's, and large health studies have shown that people who stay physically active are less likely to develop the disease. Scientists put that idea to the test.

Researchers bred mice to develop the specific kind of plaque in the brain, as seen in Alzheimer's disease. Some mice were allowed to exercise, and some were not. The autopsy results were stunning.

The brains of sedentary mice were riddled with the harmful plaques, but the physically active mice had 50 to 80 percent less plaque.

Further tests revealed that the mice who exercised produced twice as much of an enzyme in the brain that prevents plaque buildup. The exercise also produced twice as many tiny blood vessels in the brain to allow plaques to escape.

"Moving plaques from the brain into the blood, so it's carried to those organs like the liver where it can be destroyed," said Professor Sangram S. Sisodia, a neuroscientist at the the University of Chicago and lead investigator in the study.

Population studies suggest any exercise that raises your heart rate for 30 to 45 minutes at least several times a week can lower your risk of Alzheimer's. And the more the exercise you get, the lower your risk.

"Regular physical exercise is probably the best means we have of preventing Alzheimer's disease today," said Dr. Ronald Petersen, director of the Alzheimer's Research Center at the Mayo Clinic in Rochester, Minn.

"There are other possible intervention, including diet, and supplements, intellectual activities, but the data indicate that physical activity is the most likely to prevent this disease," Petersen told ABC News.

For family members determined to avoid another generation of this disease, there is finally preventative action they can take, which they won't have to wait for.

"Regular physical exercise is probably the best means we have of preventing Alzheimer's disease today." Dr. Ronald Petersen of the Mayo Clinic Alzheimer's Disease Research Center said. "Better than medications, better than intellectual activity, better than supplements and diet."