Unfortunately, only a small percentage of American children are able to log the recommended exercise every day. According to a survey by the Centers for Disease Control and Prevention, only about 27.1% of high school students did so. This could be one of the top reasons why childhood obesity is prevalent in the country and why many kids struggle in school.
http://www.indiancrestpeds.com/pediatrics/a-pediatrician-guides-you-on-precautions-for-risky-play-and-activities/