Running may give the brain a workout, too. A new study finds that individuals consistently scored higher on intellectual tests after embarking on a running program.

These improvements, however, went down when the joggers stopped their training, which suggests that ongoing exercise is required to maintain the benefit.

Recent studies have suggested that exercise benefits both brawn and brain.

Researchers at Duke University in Durham, North Carolina, reported earlier this year that seniors who embarked on a 4-month exercise program showed significant improvement in memory and other mental skills, also known as cognitive function. Other studies have shown that regular workouts can help fight depression, as well.

In the study researchers from Nihon Fukushi University in Handa, Japan had seven healthy young people initiate a jogging regimen consisting of running for 30 minutes, two to three times a week for at least 12 weeks. Each of the runners also took a series of complex computer-based tests, to compare memory skills before and after the 3-month jogging program.

After 12 weeks of jogging, scores on all of the tests "significantly increased" in the runners, as did their reaction times in completing the tests. The researchers point out that the study participants were given no time to practice the various tests between each evaluation.

These tests showed that joggers had a clear improvement in prefrontal function adding that scores began to fall again if participants stopped their running routine.

Exactly how exercise might strengthen mental sharpness is unclear, but previous research suggests that maintaining a healthy flow of blood and oxygen protects the brain. The Japanese researchers note that oxygen intake rose along with joggers' test scores.

Annual Meeting of the Society for Neuroscience, San Diego December 2001