Schoolchildren may be able to boost their classroom performance by getting out on the playing field, a study suggests.
A review of previous research found evidence that physical activity can improve academic achievement in children and teenagers.
Scientists in the Netherlands pooled data from 14 studies with sample sizes ranging from 53 to 12,000 participants aged between six and 18.
The authors, led by Dr Amika Singh, from Vrije University Medical Centre in Amsterdam, wrote in the journal Archives of Paediatrics & Adolescent Medicine: "According to the best-evidence synthesis, we found strong evidence of a significant positive relationship between physical activity and academic performance.
"The findings of one high-quality intervention study and one high-quality observational study suggest that being more physically active is positively related to improved academic performance in children."
Exercise may help mental faculties by increasing blood and oxygen flow to the brain, reducing stress and improving mood, said the researchers.
Physical activity could also boost levels of growth factors that help generate new nerve cells and assist the "rewiring" of neurons.
The researchers added: "Relatively few studies of high methodological quality have explored the relationship between physical activity and academic performance.
"More high-quality studies are needed on the dose-response relationship between physical activity and academic performance and on the explanatory mechanisms, using reliable and valid measurement instruments to assess this relationship accurately."