In an effort to raise test scores, schools have been forced to trim time from classes that don't focus on core essentials, like reading and math. "Specials," such as art, music, and physical education are also often cut when budgets get tight. But a new nationwide study done by the CDC should give school administrators pause when those decisions have to be made.

What the CDC found was that girls who spend between 70 and 300 minutes in physical education each week tended to score higher on achievement tests than girls who spent a half hour or less each week in gym class. (This finding did not apply to boys.) Researchers theorize that the added exercise improved blood flow to the brain and also reduced disruptive behaviors.

Because many struggling schools can only provide a half hour class each week, parents may need to help their kids supplement physical education with outside activities. Encouraging regular family walks and bike rides, extracurricular sports and classes, and a generally active lifestyle will teach children healthy habits for life.