High School Physical Education Requirements and Youth Body Weight: New Evidence from the YRBS
利用州级青少年风险行为调查数据，研究发现增加高中体育课程要求虽能提高体育课活动时间，但并未显著改变青少年体重，原因在于校内活动替代了校外活动。
Previous research has found that high school physical education (PE) requirements are largely ineffective at reducing youth body weight. However, these studies were forced to rely on cross-state variation in PE requirements to identify their impacts, raising concerns that estimated policy effects may be confounded by state-level unobservables. Using data from the State and National Youth Risk Behavior Surveys and exploiting recent changes in state high school PE laws, we re-examine the effect of PE requirements on body weight. Our estimates show that a one-semester increase in PE requirements is associated with a 10 to 13% increase in minutes per week spent physically active in PE classes, but with no change in net vigorous exercise and little change in youth body weight. We conclude that substitution of in-school for outside-of-school physical activity and small resultant net energy expenditures can explain the absence of body weight effects. Copyright © 2016 John Wiley & Sons, Ltd.