A new study in the US says physically fit children in the age group 9-10 tend to be brainier and often do better in memory tests, as compared to their less fit peers. The study was based on how effectively children used oxygen while running on a treadmill.

Researchers at the University of Illinois also noted that those students who were most fit also tend to have a bigger hippocampus - a structure deep in the brain important in learning.

Study leader Art Kramer said in a statement that physically fit children were much more efficient than the less-fit children at utilizing oxygen.

Kramer and colleagues used magnetic resonance imaging, for the first time in medical history, to look at differences in brain between kids who are fit and who aren't. Beyond that, he noted that it relates those measures of brain structure to cognition.