Can walking boost the memory? Can exercise increase concentration or even stave off Alzheimer's disease? A new U.S. study suggests so.

In a study at the University of South Carolina, published last month in The Journal of Applied Physiology, scientists assembled mice and assigned half of them to run for an hour daily on little treadmills, while the rest were made to lounge in their cages, without exercising.

It is an accepted truth that exercise remodels muscles, making them more durable and resistant to fatigue. This is grounded on a process that involves an increase in the number of muscle mitochondria.

Mitochondria are tiny organelles that are found in the cell's nucleus and function as the energy factories of the cell. The greater the density of the mitochondria in a cell, the greater its vitality. The upsurge in the number of these power house cells has been linked both to improvements in exercise endurance and increased longevity in animals, and reduced risk for obesity, diabetes and cardiac disease in people.

Studies in the past have shown that exercise stimulates neurogenesis, the process of creating new brain cells. But the scientists were not in the lookout for new cells. They were more interested in existing cells to see if exercise was molding thems into shape, similar to exercise strengthening muscle.

Brain cells are spurred by mitochondria as well. Scans of the brain have shown that metabolic activity in many parts surge during workouts, but it still remains unknown whether those active brain cells were adapting and changing.

The test conducted by the South Carolina scientists involved testing the mice for eight weeks. Both the sedentary control animals and runners were housed in the same laboratory to ensure that except for the treadmill sessions, the two groups shared the same environment.

At the end of the test, the running mice displayed greater endurance than the sedentary mice, lasting for about 126 minutes compared to 74 minutes.

What was more interesting is that the brains of the running mice showed markers of upwelling mitochondrial development in tissues. Other parts of the brains showed increased activity in others. Both samples though, showed that brain cells had newborn mitochondria.

The lounging mice had no comparable activity.

The exercise training in the eight week study appears to be "sufficient stimulus to increase mitochondrial biogenesis," according to Dr. J. Mark Davis, a professor of exercise science at the Arnold School of Public Health at the University of South Carolina.

"There is evidence that mitochondrial deficits in the brain may play a role in the development of neurodegenerative diseases, including Alzheimer's and Parkinson's diseases. Having a larger reservoir of mitochondria in your brain cells could provide some buffer against those conditions," according to Davis.

"Revitalized brain cells also, at least potentially, could reduce mental fatigue and sharpen your thinking even when you're not exercising," he said. "Mouse brains are not human brains, but since mitochondrial biogenesis has been shown to occur in human muscles, just as it does in animal muscles, it is a reasonable supposition that it occurs in human brains."

A 30-minute jog is probably a good human equivalent of the workout that the mice completed, Davis said.

This is like hitting two birds with one stone. Suit up and jog.