Girls who were more physically active at age 11 did better at school as teenagers, a study finds. And the most active girls really aced science.

It's become pretty much a given that children do better academically when they get regular exercise, even though schools continue to cut or even eliminate recess time. But there's surprisingly little hard evidence to back that up.

This investigation used data from a British study that has been following the health of a large group of parents and children since 1991. They measured almost 5,000 children's physical activity at age 11 by having them wear an acclerometer for a week.

Few of the children were getting the recommended 60 minutes a day of moderate to vigorous exercise. Boys clocked 29 minutes a day on average, while girls managed just 18 minutes.

The more active the 11-year-olds were, the better they did on standardized school tests of English, math and science.

The surprise was that physically active girls were much better at science than their peers. That held true for five years, when the children took other standardized tests at age 13 and 16.

"We're not sure why that would be," Josie Booth, a lecturer in developmental psychology at the University of Dundee and lead author of the study, told Shots. It could be important, given that both Europe and the United States are trying hard to get more girls involved in science. "It could obviously be a chance finding," Booth adds. "We'd like to have a chance to look further into it."

The researchers did adjust the results to account for factors that could affect school performance, including birth weight, current weight, a mother's smoking while pregnant and the family's socioeconomic situation. The results were published in the British Journal of Sports Medicine.

This study doesn't prove that the increased exercise was what improved the children's test scores, but parents aren't off base in thinking that it could help. Randomized controlled trials have shown that exercise improves brain function in older people, and a few studies have shown that in children, too.

Until Booth or other scientists can manage a randomized trial on girls, exercise and science, we'll have to just hope that bicycling or running will help our daughters become future Nobelists. (I'll hold off on booking my ticket to Stockholm for the awards ceremony.)

"There's certainly an association between more physical activity and better academic achievement," Booth says. "If parents can get their children to meet that goal of 60 minutes a day, it's going to be beneficial for a range of factors."

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