Get Up. Get Out. Don’t Sit.Posted: October 23, 2012
Just as we were all settling in front of the television to watch the baseball playoffs, two new studies about the perils of sitting have spoiled our viewing pleasure.
The research, published in separate medical journals this month, adds to a growing scientific consensus that the more time someone spends sitting, especially in front of the television, the shorter and less robust his or her life may be.
To reach that conclusion, the authors of one of the studies, published in the October issue of The British Journal of Sports Medicine, turned to data from the Australian Diabetes, Obesity and Lifestyle Study, a large, continuing survey of the health habits of almost 12,000 Australian adults.
Along with questions about general health, disease status, exercise regimens, smoking, diet and so on, the survey asked respondents how many hours per day in the previous week they had spent sitting in front of the television.
Watching television is not, of course, in and of itself hazardous, unless you doze off and accidentally slip from the couch onto a hard floor. But television viewing time is a useful, if somewhat imprecise, marker of how much someone is engaging in so-called sedentary behavior.
“People can answer a question like, ‘How much time did you spend watching TV yesterday?’ much better than a question like ‘How much time did you spend sitting yesterday?’ ” says Dr. J. Lennert Veerman, a senior research fellow at the University of Queensland, who led the new study.
Australians, as it turns out, watch lots of telly. According to the survey data, in 2008, the year that the researchers chose as their benchmark, Australian adults viewed a collective 9.8 billion hours of television.
Using complex actuarial tables and adjusting for smoking, waist circumference, dietary quality, exercise habits and other variables, the scientists were next able to isolate the specific effect that the hours of sitting seemed to be having on people’s life spans.
And the findings were sobering: Every single hour of television watched after the age of 25 reduces the viewer’s life expectancy by 21.8 minutes.
By comparison, smoking a single cigarette reduces life expectancy by about 11 minutes, the authors said.
Looking more broadly, they concluded that an adult who spends an average of six hours a day watching TV over the course of a lifetime can expect to live 4.8 years fewer than a person who does not watch TV.