Americans are becoming increasingly sedentary, spending almost a third of their waking hours sitting down, and computer use is partly to blame, a new study found.
Over almost a decade, average daily sitting time increased by roughly an hour, to about eight hours for U.S. teens and almost 6 1/2 hours for adults, according to the researchers. That includes school and work hours, but leisure-time computer use among all ages increased too.
By 2016, at least half of American kids and adults spent an hour or more of leisure time daily using computers. The biggest increase was among the oldest adults: 15% of retirement-aged adults reported using computers that often in 2003-04, soaring to more than half in 2015-16.
Most Americans of all ages watched TV or videos for at least two hours daily and that was mostly unchanged throughout the study, ranging from about 60% of kids aged 5 to 11, up to 84% of seniors.
“Everything we found is concerning,” said lead author Yin Cao, a researcher at Washington University’s medical school in St. Louis. “The overall message is prolonged sitting is highly prevalent,” despite prominent health warnings about the dangers of being too sedentary.
The researchers analyzed U.S. government health surveys from almost 52,000 Americans, starting at age 5, from 2001-2016. Total sitting time was assessed for teens and adults starting in 2007. The results were published Tuesday in the Journal of the American Medical Association.
Despite the growing alarm about the harmful effects of sitting too much, Americans are sitting more than in the past — in part because people are spending more leisure time in front of the computers.
The association between lots of sitting and bad health is now well-established, but there hasn’t been a lot of data on how sedentary Americans actually are, says Yin Cao, a cancer epidemiologist at Washington University in St. Louis and co-author of a study published today in the Journal of the American Medical Association. By analyzing data from the National Health Nutrition Examination Survey, Cao and her team found that, for both adults and teens, the total time sitting increased by about an hour per day from 2007 to 2016 (from about 6.4 hours to 8.2 hours a day).
The amount of time spent sitting and watching television or videos was generally stable between 2001 and 2016 — at least two hours a day — but as time went on, people in all age groups reported spending more of their leisure time sitting while using the computer. By 2016, half of adults reported doing this for at least an hour a day, up from 29 percent in 2003. This was true for 57 percent of teens, up from 53 percent. “[People] work indoors more than ever before and this may also change their leisure time activity as well,” explains Cao. Though using computers is now a common leisure activity, that may not have been the case in the past when computers were less ubiquitous. Cao adds that people may not be aware that sitting too much can be dangerous, especially since “there’s no clear intervention” to address this issue in most schools and workplaces.