The American Academy of Pediatrics Council on School Health has issued a policy statement on the role of recess within the school day. The statement concludes that "recess serves as a necessary break from the rigors of concentrated, academic challenges in the classroom. But equally important is the fact that safe and well-supervised recess offers cognitive, social, emotional, and physical benefits that may not be fully appreciated when a decision is made to diminish it. Recess is unique from, and a complement to, physical education—not a substitute for it. The American Academy of Pediatrics believes that recess is a crucial and necessary component of a child’s development and, as such, it should not be withheld for punitive or academic reasons."
Visit http://pediatrics.aappublications.org/content/131/1/183.full for a full text of the policy statement.