There has been an unfortuante trend in many elementary and middle schools. In order to get some additional study and class time in for high stakes testing, some schools have adopted a 'no recess' policy. Perhaps as high as 30% of kindergarten classes no longer have recess. This is unfortunate, particularly for young children. Most kids likely find recess to be a positive part of the day, and it is also a chance for younger children to get some of their energy out, so they may actually focus better in class, rather than sit their fidgeting. But there is another reason why unregulated play is a positive experience during the school day: it leads to better brain development.
The Drs. Eide have a post about the benefits of play for the brain. Play helps increase blood flow to the dentate gyrus in the brain, which plays (no pun intended) a role in memory and feelings of happiness. Play also has an effect on physical development and the development of the cerebellum. The good news for older people is that there is evidence that play and exercise continue to be beneficial to brain development over a lifetime, where memory appears to be better for those who play and exercise, and that the chances of dimentia decrease. I hope school leaders and boards of education around the country become educated in studies such as these, for this is an easy thing to provide children every day.