Despite increasing warnings about the health dangers associated with sitting for prolonged periods, U.S. residents are for the most part either maintaining or increasing their levels of such inactivity. Recent research has tied sitting for extended periods with a higher risk for obesity, diabetes, cardiovascular disease and certain cancers as well as a higher chance of death.

Researchers at Washington University School of Medicine in St. Louis analyzed data on reported sitting trends among 51,896 individuals who participated in the National Health and Nutrition Examination Survey, which draws on a representative sample of the U.S. population. They published their findings in the Journal of the American Medical Association.

The survey respondents had an average age of 37.2 years old. Half of them were female. The study authors divided the participants into four age cohorts: children 5 through 11 years old (data spanned 2001 to 2016 for this group) whose parents provided the survey responses; adolescents 12 through 19 years old (data spanned 2003 to 2016 for them), adults 20 to 64 years old (data spanned 2003 to 2016) and adults 65 and older (data spanned 2003 to 2016).

Those who reported sitting watching television or videos for two hours per day or more included 62% of the children, 59% of the adolescents, 65% of adults 20 to 64 years old and 84% of those ages 65 and older.

During the study period, the proportion of children reporting at least two hours of TV or video watching per day declined by 3.4 percentage points, a trend that was statistically significant, meaning it was unlikely to have occurred by chance. Meanwhile, the corresponding rate declined by a statistically insignificant 4.8 percentage points among adolescents, declined by a statistically insignificant 0.7 percentage points among adults 20 to 64 years old and increased by a statistically significant 3.5 percentage points among senior citizens.

Compared with their respective counterparts, males in all age groups, African-Americans in all age groups and those who reported being obese or physically inactive were more likely to report a greater amount of time sitting watching TV or videos.

The estimated proportion of each age cohort who reported at least one hour per day of computer use outside of school or work increased in all age groups during the study period: from 43% to 56% among children, from 53% to 57% among adolescents and from 29% to 50% among adults. All these differences were statistically significant.

An estimated one in four members of the U.S. population use computers outside of school or work for at least three hours daily.

Between 2007 and 2016, the total hours spent sitting per day increased from 7 to 8.2 hours among adolescents and from 5.5 to 6.4 hours among adults. Both differences were statistically significant.

“We think a lot of these sedentary habits are formed early, so if we can make changes that help children be more active, it could pay off in the future, both for children as they grow to adulthood and for future health-care spending,” co–senior author Graham A. Colditz, MD, DrPH, MPH, said in a press release. “Sedentary behavior is linked to poor health in many areas, and if we can reduce that across the board it could have a big impact.”

To read a press release about the study, click here.

To read the study abstract, click here.