From the Atlantic:
According to the results of a Danish study released late last year, my Dutch friends are giving their daughter a less tangible but more lasting gift along with that bicycle: the ability to concentrate better. The survey looked at nearly 20,000 Danish kids between the ages of 5 and 19. It found that kids who cycled or walked to school, rather than traveling by car or public transportation, performed measurably better on tasks demanding concentration, such as solving puzzles, and that the effects lasted for up to four hours after they got to school.
The connection between active transportation and better physical fitness is well-documented and intuitively easy to draw, and yet apparently not compelling enough. As the Davis Enterprise article points out, even in a U.S. city with relatively good bicycle infrastructure such as Davis, California, parents continue to drive their children to school in huge numbers. More than 60 percent of elementary students in that city arrive for class each morning with their parents behind the wheel. Nationally, as of 2009, only 13 percent of kids in the United States walked or biked to school, down from 50 percent in 1969.
Read more here.