School-Age Youth May Need One Hour of Moderate to Vigorous Physical Activity Daily to Be Healthy 

School-age youth should have 60 minutes or more of moderate to vigorous physical activity daily, according to the results of a systematic review published in the June issue of the Journal of Pediatrics . An editorialist agrees.

"We were asked to review the literature and find evidence of the impact of physical activity on the health and well-being of children and to make recommendations based on the evidence, not just on what we all believe to be beneficial," said panel cochair William B. Strong, MD, from the Medical College of Georgia, in a news release. "The take-home message for parents is that it is very important to ensure that their children spend at least an hour a day in some form of appropriate physical activity. "

The 13-member expert panel conducted a systematic literature review of 850 articles and additional articles for strength of evidence, conclusions, key issues, and gaps in evidence. Outcomes of physical activity interventions included body fat, lipid levels, and measures of self-perception.

Evidence-based data were strong for beneficial effects of physical activity on musculoskeletal health, several components of cardiovascular health, adiposity in overweight youth, and blood pressure in mildly hypertensive adolescents. Evidence was adequate to make informed judgments about the benefits of physical activity on lipid and lipoprotein levels and adiposity in normal-weight children and adolescents; blood pressure in normotensive youth; other cardiovascular variables; self-concept, anxiety, and depression symptoms; and academic performance.

Although metabolic syndrome in youth is not clearly defined, regulation of weight through physical activity appears to have a beneficial effect on components of the syndrome.

"The important thing is we have to get American children and adolescents active," said cochair Robert M. Malina, MD, from Tarleton State University in Stephenville , Texas . "The evidence is very clear that physical activity has decreased dramatically in the last 10 to 20 years."

Most intervention studies reviewed by the panel used supervised programs of moderate to vigorous physical activity lasting 30 to 45 minutes for three to five days per week. However, the panel concluded that more physical activity would be needed to achieve similar benefits on health and behavioral outcomes in ordinary daily circumstances, in which activity is typically intermittent and unsupervised.

They noted that exercise should be developmentally appropriate, be enjoyable, and involve a variety of activities, such as jumping rope, soccer, basketball, and brisk walking. However, they cautioned that sedentary children should increase activity gradually.

"Youngsters tend to get bored easily so they have to have variety," said Dr. Malina. "In addition, youngsters like physical activities that are challenging."

Without compromising academics, most of the recommended activity could take place at school through appropriate physical education, recess, intramural sports, and before- and after-school programs. Parents, pediatricians, day-care centers, preschools, and communities should also do their part to encourage healthy activity, according to the panel.

"All of us need to help children increase the amount of time spent in moderate to vigorous physical activity," Dr. Malina said. "This means that parents, coaches, teachers and others who influence youngsters need to become active role models and get children involved with regular participation in physical activity."

In an accompanying editorial, William H. Dietz, MD, PhD, from the Centers for Disease Control and Prevention (CDC) in Atlanta , Georgia , notes that the gaps in knowledge identified by the review should fuel research for years to come.