The World Health Organization recommends that youth participate in a minimum of 60 minutes of moderate to vigorous physical activity (MVPA) each day. Studies have shown that youth experience most of their MVPA during school hours. Therefore, it stands to reason that increasing outdoor time after school hours would increase MVPA. In a new study scheduled for publication in The Journal of Pediatrics, researchers confirmed that time spent outdoors after school was positively associated with MVPA.
Drs. Lee Schaefer and Jonathan McGavock, along with colleagues at the University of Alberta, studied 306 youths (9-17 years of age) enrolled in the Healthy Hearts Prospective Cohort Study of Physical Activity and Cardiometabolic Health. During the winter and spring of the 2008/2009 academic year, participants wore an accelerometer and completed an online survey that included a self-report of time spent outdoors after school, including organized activities and free play.
The results showed that youth who reported that they did not spend time outdoors after school (17%) achieved 21 fewer minutes of MVPA daily, with an additional 70 minutes per day of sedentary behavior compared with those who reported spending most of their time outdoors after school (39%). In general, youth who spent most of their time outdoors after school were three times more likely to meet guidelines for daily physical activity and had significantly higher cardiorespiratory fitness levels than their peers who did not spend time outdoors; the positive effects of outdoor activity held true even in the winter months.
Although this study found that 34% of youth achieved the recommended 60 minutes of MVPA each day, more work is needed. These findings support calls for promoting outdoor activities as a means of increasing MVPA in youth. Because youth spend a substantial amount of time in school, school wellness policies should include plans designed to increase outdoor activity. According to Dr. Schaefer, "Schools and parents should consider structured time outdoors for children in an effort to boost physical activity levels and enhance [cardiorespiratory] fitness."