The findings come from mouse studies reported in the May 22 online edition of the Annals of Neurology, the research publication of the American Neurological Association. The lead author is Gerd Kempermann, MD, of the Max Delbrück Center for Molecular Medicine in Berlin, Germany.
"Our study suggests that, in mice, we can reduce the effects of aging on the brain with a sustained active and challenging life, even if this stimulation is only begun in middle age," Kempermann says in a news release.
The researchers put 30 adult female mice in an "enriched environment" for 10 months. They had large, specially designed cages with a square meter of floor space, plastic tubes that could be rearranged, a running wheel, nesting materials, and toys. They were allowed as much food and water as they wanted.
After living this active lifestyle, the mice were strikingly different from mice kept in standard cages. Their brains grew five times more new cells. They were better able to learn new things. They were more curious about their surroundings and more active. And they had fewer signs of age-related brain degeneration.
Researchers usually warn that people shouldn't change their behavior based on mouse studies. But this time, Kempermann says it couldn't hurt.
"Activity will certainly do no harm and most likely benefit people if they use our results as a motivation to be more active," he says. "They might even do something good for the nerve cells that are involved in learning and memory processes."
The chemical is called hs-CRP. It is a sign of inflammation -- the body's protective response to injury or infection.
"This is the first study to show that such markers of inflammation are raised long before clinical dementia appears," lead author Lenore J. Launer, PhD, says in a news release.
Launer is a researcher at the National Institute on Aging in Bethesda, Md. Her research team looked at data collected from Japanese-American men seen for the first time in 1968 through 1970 and again 25 years later.
Men with the lowest levels of hs-CRP in their blood were three times less likely to suffer dementia than those with higher levels of the substance. Inflammation is suspected of increasing risk of heart disease as well. This leads the researchers to suggest that inflammation may be linked to many diseases involving the blood vessels. -->