A MAJOR review of 14 studies has boosted evidence for the theory that physical activity can help students' academic performance.
But the authors said more research was needed to establish the ''dose'' of exercise needed.
A team, led by Amika Singh of the EMGO Institute for Health and Care Research in the Netherlands, conducted the research because of concerns that pressure to improve academic results could lead to additional time in schools for subjects such as maths and languages at the expense of time for physical activity.
It found evidence of a significant longitudinal positive relationship between physical activity and academic performance.
Dr Singh said that there was a strong belief that physical activity was linked to enhancement of brain function and cognition, thereby positively influencing academic performance.
This could be caused by increased blood and oxygen flow to the brain, increased levels of norepinephrine and endorphins and increased growth factors that helped to create new nerve cells.
''Beside these, suggested physiological effects of regular participation in sport activities may improve children's behaviour in the classroom, increasing the odds of better concentration on the academic content of these lessons,'' she said.
Dr Singh said more studies were needed to ''thoroughly examine the dose-response relationship between physical activity and academic performance as well as explanatory mechanisms for this relationship''.