People don't have to run marathons to keep their brain cells in shape -- regular, light activity may do the trick.
In the first study to show that lifelong exercise decreases cellular aging in the brain, scientists from the McKnight Brain Institute of the University of Florida say that moderately active rats have healthier DNA and more robust brain cells than their less active counterparts. The research was presented at the Society for Neuroscience's 35th annual meeting in Washington, D.C.
"It would be wonderful if we had a pill that contained all the benefits of exercise, but we don't," said Thomas Foster, Ph.D., the Evelyn F. McKnight chair for brain research in memory loss at the College of Medicine. "For this study animals were not forced to run; they did it because it was entertaining, the same as a pet hamster on a running wheel. The results show that regular mild exercise can prevent oxidative damage. In people, that translates to a daily 30-minute walk or a light 1-mile run."
Oxidative damage in the brain is believed to be a natural consequence of aging and a contributor to memory loss. In addition, increased oxidative damage has been implicated in the loss of brain cells that is associated with Alzheimer's disease and Parkinson's disease.
Oxidative damage can occur when molecules of oxygen gain electrons and become free radicals. The free radicals regain their balance by giving electrons to their neighbors. Most of the time the body routinely handles these renegades, but sometimes not before extensive damage occurs in the cell. Working with Christiaan Leeuwenburgh, Ph.D., an associate professor of aging and geriatric research at UF's Institute on Aging, Foster looked at groups of rats that had lived to old age. Some were more sedentary, while others had access to an exercise wheel.
At the end of the experiment, scientists examined chemical compounds in 41 tissue samples taken from a part of the brain important for balance and movement.
The more active rats were found to have fewer byproducts of oxidative stress in their brains. Fats known as lipids that help stabilize cell membranes, and DNA, the molecule that contains our genetic blueprint, both better withstood the rigors of time.
"The DNA for these animals after two years looked as if it were from their younger counterparts of only about 6 months of age," Foster said. "It shows a little bit of exercise may stimulate the body to fight stress that's normally occurring in the brain."