Living in the age of Netflix, streaming video games, and endless movie options, it is perhaps not that surprising that Americans are spending a dangerous amount of time sitting for prolonged periods. But the uptick in our sitting habits has changed dramatically since the earlier part of the decade: Measuring the amount of time the average American spends in seated repose, an investigation published in JAMA tells us exactly where stand — or, more aptly, sit.
Based on survey results from 51,896 individuals, this study found that, in 2016, American adolescents 12-19 years old spent 8.2 hours per day sitting and that adults over age 20 spent 6.4 hours per day sitting.
This shows very significant increases compared to 2007 sitting trends: People in each age group spent, on average, at least one more seated hour per day. What’s particularly interesting is what people are actually doing while they sit for that extra hour.
First study author Chao Cao, MPH, a data analyst at Washington University School of Medicine’s division of public health sciences, says that TV watching is typically used to categorize seated behavior. However, she tells Inverse, it’s time to start looking more closely at the time we spend using other devices —especially computers — to measure how much time we spend sitting, as anyone who has relinquished a cable account in favor of a streaming service can attest to.
“Going forward we definitely should rethink how we categorize seated time,” Cao says. “Not necessarily to include computer use as opposed to television use, but perhaps more details on the the context of seated time should be captured to keep up with the rapidly changing technology use associated with sedentary behaviors.”
What Are We Actually Doing When We Sit?
TV watching remains, for now, the “most frequently studied sedentary behavior” in children and adults, says Cao, and it’s well established that TV watching is linked to obesity. The new paper suggests that other types of media use in addition to TV will drive future trends in seated behavior — and likely have the same health consequences. Our seated time looks a lot different than it did even in the early 2000s.
According to Cao’s analysis, computer use has increased steadily, adding more seated time to the day. In 2003, 29 percent of adults reported using computers outside of work or school for at least an hour per day. But by 2016, that increased to 50 percent. Overall, extra computer use is likely the force that will drive us toward more prolonged sitting, and Cao and his co-authors drive that point home in their paper
“Of note, the substantial rise in total sitting time among adolescents and adults appears to be attributable to sedentary behaviors other than television or video watching, which was likely driven in part by the observed increases in computer use,” they write.
For its part, TV use in adults has remained relatively high, with 65 percent of adults watching at least two hours of TV per day. That number, Cao’s work shows, has actually remained stable since 2001, so the additional increase in sedentary behavior can be chalked up to computer use.
Does it Matter Why We Sit?
Whether we spend our extra seated hours in front of the TV or the computer, the result is the same: Prolonged sitting is linked to more serious health conditions. A paper published in March in Epidemiology and Community Health, for example, linked sitting for more than six hours per day to 16.9 percent of type two diabetes cases, 4.9 percent of cardiovascular disease cases, and 11.6 percent of deaths due to all-cause mortality in the UK.
Fortunately, knowing why people are sitting helps describe the “landscape” of sedentary behavior and thus lead to better policy solutions, adds Cao. We’ve already tacked on an extra hour of sitting per day in the past 15 years, so understanding why that’s happening can not only help individuals find ways to cut back on seat behavior but also influence public health strategies to keep people moving.
“As behavior change is a complex process, it’s difficult to envision a decreasing trend in sedentary behaviors at this time,” says Cao. “We would like to work with the public and policy sectors to implement the knowledge we already have to reduce excessive sitting.”
At this point, it seems that if you’re looking to limit how much you sit, it may be worth taking a look at how many hours you spend online — in addition to watching TV.
Design, Setting, and Participants: A serial, cross-sectional analysis of the US nationally representative data from the National Health and Nutrition Examination Survey (NHANES) among children aged 5 through 11 years (2001-2016); adolescents, 12 through 19 years (2003-2016); and adults, 20 years or older (2003-2016).
Exposures: Survey cycle.
Main Outcomes and Measures: Prevalence of sitting watching television or videos for 2 h/d or more, computer use outside work or school for 1 h/d or more, and total sitting time (h/d in those aged ≥12 years).
Results: Data on 51 896 individuals (mean, 37.2 years [SE, 0.19]; 25 968 [50%] female) were analyzed from 2001-2016 NHANES data, including 10 359 children, 9639 adolescents, and 31 898 adults. The estimated prevalence of sitting watching television or videos for 2 h/d or more was high among all ages (children, 62% [95% CI, 57% to 67%]; adolescents, 59% [95% CI, 54% to 65%]; adults, 65% [95% CI, 61% to 69%]; adults aged 20-64 years, 62% [95% CI, 58% to 66%]; and ≥65 years, 84% [95% CI, 81% to 88%] in the 2015-2016 cycle). From 2001 through 2016, the trends decreased among children over time (difference, −3.4% [95% CI, −11% to 4.5%]; P for trend =.004), driven by non-Hispanic white children; were stable among adolescents (−4.8% [95% CI, −12% to 2.3%]; P for trend =.60) and among adults aged 20 through 64 years (−0.7% [95% CI, −5.6% to 4.1%]; P for trend =.82); but increased among adults aged 65 years or older (difference, 3.5% [95% CI, −1.2% to 8.1%]; P for trend =.03). The estimated prevalence of computer use outside school or work for 1 h/d or more increased in all ages (children, 43% [95% CI, 40% to 46%] to 56% [95% CI, 49% to 63%] from 2001 to 2016; difference, 13% [95% CI, 5.6% to 21%]; P for trend <.001; adolescents, 53% [95% CI, 47% to 58%] to 57% [95% CI, 53% to 62%] from 2003 to 2016, difference, 4.8% [95% CI, −1.8% to 11%]; P for trend =.002; adults, 29% [27% to 32%] to 50% [48% to 53%] from 2003 to 2016, difference, 21% [95% CI, 18% to 25%]; P for trend <.001). From 2007 to 2016, total hours per day of sitting time increased among adolescents (7.0 [95% CI, 6.7 to 7.4] to 8.2 [95% CI, 7.9 to 8.4], difference, 1.1 [95% CI, 0.7 to 1.5]) and adults (5.5 [95% CI, 5.2 to 5.7] to 6.4 [95% CI, 6.2 to 6.6]; difference, 1.0 [95% CI, 0.7 to 1.3]; P for trend <.001 for both).
Conclusions and Relevance: In this nationally representative survey of the US population from 2001 through 2016, the estimated prevalence of sitting watching television or videos for at least 2 hours per day generally remained high and stable. The estimated prevalence of computer use during leisure-time increased among all age groups, and the estimated total sitting time increased among adolescents and adults.