Sedentary behaviour is on the rise and Americans now sit more than ever, according to research by Canadian and American scientists. Their results were published in JAMA.
Sedentary behaviour involves waking behaviours that are low in energy expenditure — examples include sitting at work, lying down and browsing on your phone, or being couch-bound and watching Netflix for hours on end. Our bodies didn’t evolve to be like this, as we historically spent most of our waking life standing, moving, lifting, walking, and so on.
Getcanadastanding.org reports that in the 1960s, more than half of us had moderate physical activity incorporated into our workplace, but this has dwindled down to 15% today. The consequences of prolonged sitting are profound: there’s a higher risk of heart disease, diabetes, obesity, mental health problems, and cancer, in tandem with more immediate physiological issues like back, wrist, and neck pain.
Average sitting time has risen by an hour in last decade
Researchers studied some 51,000 people using US government survey data from 2001 through 2016. They looked for trends in total time spent sitting daily doing various activities, like watching television or using the computer. An important note about this study is that it was the first to examine a nationally-representative population sample; the participants were diverse in ethnicity and ages ranged from young kids to the elderly.
The team found that, over the course of nearly a decade (2007 to 2016), the average sitting time for Americans increased by approximately an hour to around 8 hours per day for teens and 6.5 hours for adults. Naturally, this includes school and work commitments, but the elephant in the room is our relationship with screens, particularly computers.
Among kids aged 5-11, 62% were found to watch videos for at least two hours daily, a significant finding given that habits formed early in life can set the stage for problems later on.
“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,” says co-author Graham A. Colditz. “Sedentary behaviour is linked to poor health in many areas, and if we can reduce that across the board it could have a big impact.”
Across all age groups, between 13% and 23% of participants were found to watch videos for more than four hours a day. Being male, non-Hispanic black, and obese were the most likely factors associated with excessive sedentary behaviour.
The biggest jump in any age category was with the elderly: 15% of adults aged 65 and above reported spending at least an hour of leisure time on the computer back in 2003-04, but this shot up to over half of participants by 2015-16.
“In almost none of the groups we analyzed are the numbers going in the right direction,” says lead author Yin Cao. “We want to raise awareness about this issue on multiple levels — from individuals and families to schools, employers and elected officials.”
Getcanadastanding.org reports that Canadians are sedentary for an average of 10 hours a day. Previous research from Statistics Canada suggests that 85% of Canadians do not meet guidelines for the recommended amount of physical activity per week needed for good health. A growing body of evidence from researchers in other countries like Australia and the UK shows that the issue is prevalent in other parts of the world.
With the data from this study, researchers believe they have the blueprint to start probing with interventions and programs to reduce the amount of time we’re stuck in chairs.
“Until now, we haven’t had data demonstrating the amount of time most Americans spend sitting watching TV or doing other sedentary activities,” says Cao.
“Now that we have a baseline — on a population level and for different age groups — we can look at trends over time and see whether different interventions or public health initiatives are effective in reducing the time spent sitting and nudging people toward more active behaviours.”