Jog Away From Alzheimer's Disease

Running rats show value of exercise in brain health

WEDNESDAY, May 29 (HealthDayNews)-- You might be able to run Alzheimer's disease into the ground.

A new animal study has found that exercise-happy rats are more likely to have healthy brains than the rodent equivalents of couch potatoes.

Humans are, of course, more complex than rats. However, the two species have enough in common to make biologists at the University of California at Irvine think they may be on to something after observing hundreds of rats go about their daily lives.

"The message is that moderate exercise is not only good for your body, it's good for your brain," says Nicole Berchtold, a post-doctoral neurobiology researcher who co-authored the study, which appears in the June issue of Trends in Neurosciences.

Researchers have known for years that elderly people who exercise are more mentally fit than those who don't, Berchtold says. Their reaction times are quicker and their cognitive skills are better, she adds.

However, the exact connection between exercise and the brain hasn't been clear.

Researchers at UC Irvine measured the daily exercise levels of rats that were allowed to run in wheels whenever they wished. "They could do as much or as little exercise as they wanted," Berchtold says.

Many of the rats ran from a bit more than half a mile to 2.5 miles a day; some even went as far as nine miles.

Researchers then examined the molecular makeup of the brains of the rats. "We looked in a couple different brain areas, not really knowing what to expect," Berchtold says.

Researchers were surprised to find changes in parts of the brain that control thinking and learning, not just in those that handle decisions about movement. In rats that ran at least 500 meters on a regular basis, exercise appeared to trigger a so-called "growth factor" that plays a role in better brain functioning, she explains.

In turn, the heightened activity of the growth factor may stimulate memory and learning, protecting the brain against deterioration from Alzheimer's disease.

Berchtold says it's difficult to translate the exercise levels in the rats to equivalents in humans. However, it does appear clear that exercise every other day was as effective in stimulating the brain as exercise every day, she says.

One expert cautions that while researchers know a healthy lifestyle can prevent cancer and heart disease, no one has proven a direct link between exercise and lower rates of Alzheimer's disease.

"We don't know definitively," says Jennie Ward Robinson, director of medical and scientific affairs at the Alzheimer's Association.

What To Do

Information about Alzheimer's disease is available from the Alzheimer's Association or the National Institute on Aging's Alzheimer's Disease Education and Referral Center.

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