Physical Activity and Sedentary Behavior


The U.S. Department of Health and Human Services recommends that children and adolescents get 1 hour or more of physical activity every day, most of which should be moderate- to vigorous-intensity aerobic activity.1 Data from the 2013 Youth Risk Behavior Surveillance System showed that 27.1 percent of high school students were physically active for at least 60 minutes on each of the 7 previous days (Figure 1).

physical activity by grade

Figure 1 Source

Achievement of recommended levels of physical activity varied by both sex and grade level. Among high school students in all grades, a smaller proportion of females reported 60 minutes of physical activity on each of the previous 7 days than males (17.7 versus 36.6 percent, respectively). Students in the 9th grade were more likely to achieve the recommended level of physical activity than those in the 12th grade (30.4 versus 24.3 percent, respectively). With regard to race and ethnicity, 21.8 percent of non-Hispanic Asian students reported recommended levels of physical activity, compared to 28.2 percent of non-Hispanic Whites.

In conjunction with physical activity, experts recommend limiting sedentary behaviors. Specifically, the American Academy of Pediatrics recommends that parents limit children’s media time to 1–2 hours per day.2 This includes time spent watching TV or videos as well as time spent playing video or computer games. In 2013, 32.5 percent of high school students reported watching 3 or more hours of television per day on an average school day. There was no difference in the proportion of males and females who reported this level of television watching. However, students in 9th grade were slightly more likely to watch 3 or more hours of television than students in 12th grade (34.9 versus 31.3 percent, respectively).

The proportion of students who reported 3 or more hours of television watching varied significantly by race and ethnicity (Figure 2). More than half of non-Hispanic Black students (53.7 percent) reported this level of television viewing, while the same was true for about one-quarter of non-Hispanic White and Asian students (25.0 and 24.5 percent, respectively) and more than one-third of Hispanic students (37.8 percent).

sedentary behavior by race-ethnicity

Figure 2 Source

In the same year, 41.3 percent of high school students reported playing video games or using computers for something other than school work, such as computer games, for 3 or more hours per day on an average school day. The proportion varied by grade level, as 9th-grade students were more likely to engage in this behavior than those in 12th grade (44.8 versus 36.9 percent, respectively). These activities varied by race and ethnicity, with non-Hispanic Asian (51.5 percent) and non-Hispanic Black students (49.1 percent) more likely to report this level of video game and computer use than non-Hispanic White students (37.4 percent).

Data Sources

Figure 1. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. High School Youth Risk Behavior Survey. Accessed September 20, 2014.

Figure 2. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. High School Youth Risk Behavior Survey. Accessed September 20, 2014.


1 U.S. Department of Health and Human Services. 2008 Physical Activity Guidelines for Americans. Accessed September 2, 2014.

2 Committee on Public Education. Children, adolescents, and television. Pediatrics. 2001;107(2):423–426.


Statistical Significance Test

Calculate the difference between two estimates:

Calculated Z-Test Result 0.9567433 Not statistically significant

We follow statistical conventions in defining a significant difference by a p-value less than 0.05 where there is a less than 5% probability of observing a difference of that magnitude or greater by chance alone if there were really no difference between estimates. The 95% confidence interval includes a plausible range of values for the observed difference; 95% of random samples would include the true difference with fewer than 5% of random samples failing to capture the true difference.

This website allows comparisons between two estimates using the independent z-test for differences in rates or proportions. This test is appropriate for comparing independent populations across years (e.g., 2011 versus 2012) or subgroups (e.g., Male versus Female) on corresponding measures. To the extent possible, the functionality of this application has limited estimate comparisons based on appropriate use of the independent z-test. However, some tables present subgroup categories within broader categories that will allow comparisons between non-independent populations (e.g., low birth weight and very low birth weight). Users should exercise caution when interpreting these test results, which will frequently overstate statistical significance.

For some tables, the website does not allow for comparisons between two estimates, even though the data represent independent populations. Generally, this is because the standard errors were not publicly available at the time this website was created.