Physical activity in children and adolescents.

After obesity rates in youth reached alarming rates, public health officials recognized the need for specific physical activity guidelines for children and adolescents. Numerous health care groups and sports and fitness organizations collaborated on the development of the Physical Activity Guidelines for Americans in 2008, which have been widely endorsed and include recommendations for the pediatric population. Children and adolescents should participate in moderate-to-vigorous physical activity 1 or more hours per day and muscle and bone-strengthening activities 3 or more times per week. Physical activities should be age appropriate, enjoyable, and varied and occur beyond what is required for typical activities of daily living. Adequate exercise in youth improves strength, cardiorespiratory fitness, and body composition and therefore decreases cardiovascular risk factors. An improved cardiovascular profile provides a continued benefit in adulthood. Exercise also improves bone health, psychological well-being, cognition, and school performance and may decrease the risk of sports injury. Exercise habits established in childhood often continue into adulthood.