Child/Adolescent Health

Mandating more time in school PE classes may not increase exercise or weight loss among American children

American children are gaining weight at an alarming rate, with the percentage of overweight adolescents more than tripling since the late 1960s. At the same time, school physical education (PE) requirements have been shrinking. From 1991 to 2003, the percentage of U.S. high school students enrolled in daily PE classes dropped from 42 percent to 28 percent. In 2005, legislatures in 44 States introduced bills to increase or reform school PE; however, a new study suggests that mandating more time in gym classes may not result in more exercise or weight loss among American children. Agency for Healthcare Research and Quality researcher Chad Meyerhoefer, Ph.D., and colleagues analyzed data from a 2001 report of the National Association for Sport and Physical Education and a survey of youth risk behavior by the Centers for Disease Control and Prevention.

They compared the self-reported PE activity times, overall time engaged in vigorous exercise, lighter exercise, and strength-building activities, and body mass index (BMI) of high school students in States with different PE requirements. When States raised their PE requirements, girls, but not boys, increased the number of days they exercised vigorously for at least 20 minutes. This positive effect for girls was tempered by a decrease in the number of days girls engaged in 30 minutes or more of light physical activity, especially girls not otherwise active in team sports.

These results, combined with the lack of a clear effect of PE on BMI or the probability of being overweight, cast doubt on the effectiveness of education reforms that merely target time spent suited up for gym class, note the researchers. They point out, however, that studying the relationships between PE, physical activity, and weight is complex and requires rigorous statistical analysis. Students can be thin, active, and engaged in a physical education, but figuring out which of these came first is difficult. Also, students can be "couch potatoes," overweight, and less likely to actively participate in gym class as a result. Furthermore, schools in wealthier areas may offer more and higher quality PE, but have student populations that are already thinner and healthier, which could lead to a correlation between PE and healthy weight due to socioeconomic circumstances rather than program effectiveness.

See "Not your father's PE: Obesity, exercise, and the role of schools," by John Cawley, Ph.D., Dr. Meyerhoefer, and David Newhouse, Ph.D., in the Fall 2006 Education Next, pp. 60-66. Reprints (AHRQ Publication No. 07-R020) are available from the AHRQ Publications Clearinghouse.

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