A Danish study has found that the ability to concentrate is higher among the children who walked or cycled to school.
Children who were driven to school, or who took public transport, performed less well in a test measuring concentration levels, than those who had walked or cycled, a joint study by researchers at the universities in Copenhagen and Aarhus found.
"The exercise one uses to transport oneself to school is reflected in the level of concentration one has circa four hours later," said Niels Egelund, a co-author of the report.
The results surprised the researchers, as their hypothesis originally focused on the effects of eating breakfast and lunch on pupils' ability to concentrate.
"The results showed that having breakfast and lunch has an impact, but not very much compared to having exercised," Egelund told AFP.
"As a third-grade pupil, if you exercise and bike to school, your ability to concentrate increases to the equivalent of someone half a year further in their studies," he added.
In the survey, taken by 19,527 pupils aged five to 19 years, participants were asked about their exercise habits and were then given a basic test measuring their concentration.
"Most people know the feeling of being refreshed after having exercised, but it is surprising that the effect lasts for so long," Egelund said.