Sit Less, Live Longer?
John Neumann for redOrbit.com – Your Universe Online
According to a study to be published in the online journal BMJ Open, sitting down for more than three hours a day can reduce a person’s life expectancy by two years, even if they are otherwise physically active and refrain from dangerous sedentary habits.
Watching TV for more than two hours a day can exacerbate that problem, decreasing life expectancy by another 1.4 years, said the report which analyzed five underlying studies of nearly 167,000 people over a range of four to 14 years, reports Andrew Seidman for the Wall Street Journal.
Australian researchers found that people who claimed more than four hours a day of television viewing were 46 percent more likely to die of any cause than people who said they spent less than two hours a day watching TV. Those watching TV more than four hours a day were also 80 percent more likely to succumb to cardiovascular disease.
Professor David Spiegelhalter, an expert in risk calculations at the University of Cambridge, said, “This is a study of populations, and does not tell you personally what the effect of getting off the sofa might be. It seems plausible that if future generations moved around a bit more, then they might live longer on average.”
“But very few of us currently spend less than three hours sitting each day, and so this seems a very optimistic target.”
Finding a link however, is not the same as proving one thing actually causes the other. This latest piece of research does not claim to be proof, the researchers themselves acknowledge there are flaws that make its findings less than reliable.
The work looked at a large sample of people – almost 167,000 in total – but did not scrutinize the different lifestyles these individuals led. It is not clear how many of these people were less healthy to begin with and who, therefore, might spend more time sitting down as a result, reports Michelle Roberts, Health editor for BBC News online.
The studies also relied on the participants accurately recalling and reporting how much time they spent not engaged in exercise-like activities.
However, while the evidence linking sedentary behavior to various illnesses is mounting, it remains difficult for many people to find time to get on their feet, especially if they work at jobs that require sitting at a desk.
“Try to stand as much as you can,” Dr. Katzmarzyk said. “Typically when you’re on the telephone you can stand with speaker phone. Instead of emailing someone in the office, just get up and go talk to them.”
When you’re sitting and completely inactive, “you run into trouble managing blood glucose,” a researcher said.
Scientists reported last year that people who worked 10 years in sedentary jobs, or jobs that don’t require a lot of energy expenditure, had twice the risk of colon cancer and a 44 percent increased risk of rectal cancer, compared with people who had never worked sedentary jobs.
And in March of this year, scientists found that the rate of cancers linked to obesity and lack of physical activity, such as cancers of the kidney, pancreas, lower esophagus and uterus, rose every year from 1999 through 2008.
Natasha Stewart, senior cardiac nurse at the British Heart Foundation, said, “This research only suggests a causal association between sedentary behavior and a shorter life expectancy. It also used American data so we’d need to see more research to understand what it means for the UK population. However, it does highlight what we already know about sedentary behavior being a risk factor for developing heart disease. And recent UK guidelines suggested we should all minimize the time we spend sitting down.”
“We all need to be regularly active to keep our hearts healthy. So whether it’s by walking to the local shop rather than driving, or playing sport rather than watching it on TV, there are lots of ways to be more active and improve your health.”