CHICAGO, April 23 (Xinhua) -- Most Americans continue to sit for prolonged periods despite public health messages that such inactivity increases the risk of obesity, diabetes, heart disease and certain cancers, a study of Washington University School of Medicine in St. Louis said.
The researchers analyzed data from more than 51,000 people who participated in the National Health and Nutrition Examination Survey between 2001 and 2016, looking at four age groups: children aged 5 to 11, adolescents aged 12 to 19, adults aged 20 to 64, and adults aged 65 and older. Race and ethnicity were defined as non-Hispanic white, non-Hispanic black, Hispanic and other races, including multiracial.
Total daily sitting time increased among adolescents and adults from 2007 to 2016, from seven hours per day to just over eight for teenagers, and from 5.5 hours per day to almost 6.5 for adults, the researchers found.
The researchers found that most Americans spend at least two hours per day sitting and watching television or videos. Among children aged 5-11, 62 percent spent at least that long in front of screens daily. For adolescents aged 12-19, that number was 59 percent. About 65 percent of adults aged 20 to 64 spent at least two hours watching television per day. And most recently, from 2015 to 2016, 84 percent of adults aged 65 and above spent at least that much time sitting watching television. And this remained steady over the course of the study.
Across all age groups, 28 percent to 38 percent of those surveyed spent at least three hours per day watching television or videos, and 13 percent to 23 percent spent four hours or more engaged in watching television or videos.
Importantly, males of all age groups, non-Hispanic black individuals of all age groups and participants who reported being obese or physically inactive were more likely to spend more time sitting to watch televisions or videos compared to their counterparts.
In addition, computer screen time outside of work and school increased over this period. At least half of individuals across all age groups used a computer during leisure time for more than one hour per day in the two most recent years of the study. And up to a quarter of the U.S. population used computers outside of work and school for three hours or more.
Sedentary behavior is linked to poor health in many areas. The Physical Activity Guidelines for Americans published in 2018 by the U.S. Department of Health and Human Services recommends less sitting time.
The study was published on Tuesday in the Journal of the American Medical Association.