NEW YORK (Reuters Health) - Getting students to exercise more might not just address obesity issues but also improve their grades with a U.S. study finding physically fit students tend to score higher in tests than their less fit peers.

Joggers are seen along a waterfront in a file photo. REUTERS/Arko Data

Test scores dropped more than one point for each extra minute it took middle and high school students to complete a one mile run/walk fitness test, according to Dr. William J. McCarthy and colleagues at the University of California in Los Angeles.

Schools and parents seeking to optimize their students’ academic performance should take heed, McCarthy noted in an email to Reuters Health.

For optimal brain function “it’s good to be both aerobically fit and to have a healthy body shape.”

McCarthy and colleagues compared physical fitness and body weight measures with scores on California’s standardized math, reading, and language tests among 749 fifth-graders, 761 seventh-graders, and 479 ninth-graders who attended schools in Southern California between 2002 and 2003.

About half of the students were girls, 60 percent were white, 26 percent were of Hispanic ethnicity, and about 7 percent each were African American and Asian/Pacific Islander.

Almost 32 percent of the students were overweight and about 28 percent were obese, the researchers report in The Journal of Pediatrics. The researchers estimated students’ aerobic fitness according to their one-mile run/walk time on a flat track. With a 15-minute maximum allowed time to complete the test, the boys averaged slightly less than 10 minutes, while the girls averaged a little less than 11 minutes.

McCarthy’s team found that nearly two thirds of the students (65 percent) fell below the state fitness standard for their age and gender. Compared with these students, students who met or exceeded fitness standards had higher average test scores. Allowing for age, social and economic status, gender, ethnicity, and body size did not significantly alter this association.

Compared with students of desirable weight, overweight and obese students also scored significantly lower on tests, the researchers found.

These findings, McCarthy’s team notes, confirm and extend those of previous investigations. They say further studies are needed to figure out why aerobic fitness may play a role in academic performance.

If future studies confirm a cause-and-effect link between lower fitness and reduced academic performance, “schools will have to reverse their recent disinvestment in physical education ostensibly for the purposes of boosting student achievement,” they concluded.