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Physical Activity Across the Curriculum (PAAC) 
incorporated 
vigorous- and moderate-intensity physical activity into academic lessons 
delivered by elementary classroom teachers. After 3 years, students in 
classrooms averaging 
≥
75 minutes per week of PAAC activity had more 
favorable body mass index (BMI) scores (Donnelly et al., 2009).

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Copyright © National Academy of Sciences. All rights reserved.
Educating the Student Body: Taking Physical Activity and Physical Education to School
The Effectiveness of Physical Activity and Physical Education Policies and Programs
 
333
Status and Trends
The committee found no information on trends in the volume of class-
room physical activity and only one study providing an estimate of the 
proportion of the daily total step count accumulated during classroom time. 
A study of 6th-grade students near Phoenix, Arizona, using pedometers 
to measure physical activity found that about 20 percent of the daily step 
count during school hours occurred during instructional classroom time for 
both boys and girls (Tudor-Locke et al., 2006). Baseline levels of classroom 
physical activity are likely to vary by grade, race/ethnicity, sex, students’ 
socioeconomic status, subject, geographic location, and other factors.
Impact on Physical Activity
Although vigorous- or moderate-intensity physical activity is possible 
during normal classroom time, classroom physical activity is more likely 
to involve shifts from sedentary to light-intensity activities. Within the 
past decade, research has demonstrated that shifting the amount of time 
spent in sedentary activities (metabolic equivalent [MET] values 
≤
1.5) to 
light-intensity activities (MET values >1.5-<3.0) results in improved health 
outcomes for adults (e.g., Wijndaele et al., 2010, 2011; Grøntved and Hu, 
2011; Matthews et al., 2012). Likewise, a qualitative review of 232 studies 
of children aged 5-17 found a dose-response relationship between more 
sedentary behavior and negative health outcomes, including unfavorable 
body composition and decreased fitness, lower scores for self-esteem and 
prosocial behavior, and decreased academic achievement (Tremblay et al., 
2011). On the other hand, cohort studies that have controlled for vigorous- 
or moderate-intensity physical activity have yet to demonstrate a relation-
ship between reductions in sedentary activity (which is the same as increases 
in light-intensity activity) and health or risk factor outcomes (Carson and 
Janssen, 2011; Ekelund et al., 2012). The implications of these findings are 
still being discussed and have not yet been explicated in current physical 
activity recommendations. Nonetheless, it appears prudent to assume that, 
while vigorous- or moderate-intensity physical activity may have more or 
unique physical (including brain) health and cognitive benefits for children, 
light-intensity physical activity is preferable to sedentary activity from both 
health and academic perspectives. Therefore, modifications that increase 
light-intensity activity in the classroom should be viewed as beneficial even 
though no change in the volume of vigorous- or moderate-intensity physical 
activity occurs.
Isolating the impact of classroom physical activity interventions on the 
overall physical activity of children and adolescents is a frustrating venture. 
Many efforts to increase classroom physical activity are imbedded within 
programs also designed to increase activity during physical education, 

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Copyright © National Academy of Sciences. All rights reserved.
Educating the Student Body: Taking Physical Activity and Physical Education to School
334