And now, a new analysis of several studies on long periods of sedentary behavior has concluded that sitting for more than three hours a day can actually take two years off your life.
And that's even if you exercise regularly and refrain from bad habits like smoking.
But there's more bad news.
They've also determined that watching TV for more than two hours a day cuts your life expectancy by another 1.4 years.
Details of the study
The researchers, Peter T. Katzmarzyk, a professor of population science at the Pennington Biomedical Research Center in Baton Rouge, La., and I-Min Lee of Brigham and Women's Hospital and Harvard Medical School, analyzed five studies of nearly 167,000 people over four to 14 years.
They used the National Health and Nutrition Examination Survey to get data on sitting habits between 2009 and 2010 and to obtain data on TV watching from 2005 to 2006 (the most recent data available).
They eliminated data on patients who had existing diseases since the ill were more likely to be sitting more than usual due to health reasons.
However, one drawback to the analysis was that it relied on self-reporting, and people tend to underestimate how much they sit.
The results were published in the journal BMJ Open.
How to beat the sedentary lifestyle
Combating the effects of sitting a lot isn't as easy as throwing in a workout here and there.
Dr. Katzmarzyk said that the detrimental effects of sitting affect even people who follow the guideline of getting 30 minutes of physical activity a day. He told The Wall Street Journal:
"We have people who can meet that guideline. However, if you're sedentary or sitting the other 20 hours a day, you're still going to be at risk for that."
A big problem is the type of lifestyle associated with a desk job, where people can sit for hours a day. For such workers, Dr. Katzmarzyk suggested trying to stand as often as possible: "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."
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