Exercise after receiving radiation to the brain is key to improving memory and mood, new research shows.

Exercise appears to prevent the decline of erasable memory, which is similar to the memory problems patients with brain tumors experience following whole-brain radiation.

"This is the type of short-term memory people use to find their car after they have parked it in a large lot," Christina Williams, Ph.D., a professor of psychology and neuroscience at the Duke University in Durham, N.C., was quoted as saying. "After radiation, this type of memory becomes impaired in many people."

In the scientists' experiment, one group of mice was kept in their cages following brain radiation, to live among other mice as they normally would -- eating and playing. A separate group of mice, however, was given access to a running wheel to use as they wanted. The mice that were able to exercise scored just as well on a memory test as normal mice did; however, the mice that did not have access to the exercise wheel did not.

It was remarkable that the irradiated, running mice were just like the normal, non-irradiated mice that didn't exercise," lead researcher and graduate student Sarah Wong-Goodrich of the Duke Department of Psychology and Neuroscience, was quoted as saying. "We were expecting some memory retention issues with a longer delay and there weren't any."

The researchers believe exercise benefits the mind by improving blood flow to the hippocampus in the brain, a key area for learning and memory.

"Once a patient gets a doctor's clearance, I think exercise is a good thing during whole-brain radiation," Lee W. Jones, Ph.D., research director of the Duke Center for Cancer Survivorship and associate professor in the Duke Department of Radiation Oncology, was quoted as saying. "I think telling patients to take it easy is the worst advice we can give, because we know they will become deconditioned physically, and this study shows exercise potentially could provide cognitive and psychological benefits."