Girls who spend more time in vigorous physical activity may do better in school, even if they are not particularly fit, study findings hint.
Dr. Lydia Kwak, at Karolinska Institute in Huddinge, Sweden, and colleagues examined associations between light, moderate, and vigorous physical activity and academic achievement in 232 students (52 percent girls) who were 16 years old on average and attending ninth grade in a Swedish school.
They tallied students' grades in language, science, math, history, and other school subjects, Kwak's team explains in the Journal of Pediatrics.
They assessed students' overall physical activity by having each wear an accelerometer—a physical activity meter similar to a pedometer—for four consecutive days that included at least one weekend day. The researchers determined students' overall fitness from timed stationery bicycle tests.
On average, Kwak noted, the girls spent 69 minutes and the boys spent 81 minutes a day in moderate activities such as hiking, skateboarding, or rollerblading, and vigorous activity such as soccer, running, tennis, and basketball.
The link between vigorous physical activity and academic achievement in girls was evident after the investigators allowed for numerous social and family factors potentially associated with academic achievement, and also for girls' individual measures of fitness.
However, in boys, who were consistently more physically active overall, only fitness appeared linked with academic achievement.
While these findings hint at an association between vigorous physical activity and academic achievement in girls, they don't say anything about cause and effect, Kwak told Reuters Health by email.
The question, she said: "Is it vigorous physical activity that influences academic achievement or academic achievement that influences vigorous physical activity?"
Answering that will require more studies, said Kwak.
SOURCE: The Journal of Pediatrics, December 2009.
© 2009 Reuters. All rights reserved. Republication or redistribution of Reuters content, including by caching, framing or similar means, is expressly prohibited without the prior written consent of Reuters.
