Pull up a chair—sitting won’t actually kill you.
For desk-bound workers, sitting has recently become a major health worry. A 2010 study in the American Journal of Epidemiology tracked 123,000 adults over 14 years and found that people who sat more than six hours a day had an 18% higher mortality rate than those whose daily chair time lasted for less than three hours. A subsequent meta study in the Journal of the National Cancer Institute looked at nearly 70,000 cancer cases and found that sitting was associated with a 24% increased risk of colon cancer, a 32% increased risk of endometrial cancer, and a 21% increased risk of lung cancer.
But a new study in the International Journal of Epidemiology came to a less disturbing conclusion. The researchers, led by Richard Pulsford of the University of Exeter, followed the physical activity of more than 5,100 people in London starting in 1997, measuring the time they spent sitting at work, in front of the TV, and in other places. Last year, Pulsford and his colleagues tested to see if those who spent more time sitting faced an increased risk of dying. They did not.
“No associations were observed between any of the five sitting indicators and mortality,” the research concluded.
But the group that the researchers observed, civil servants aged between 35 and 55, were not your average indolent Brits. They engaged in moderate to vigorous activity for an average of almost 12 hours per week and walked about 40 minutes a day (got to love those convoluted London commutes). The UK government recommends at least two-and-a-half hours of moderate to vigorous activity a week; a large share of Brits don’t achieve this.
In other words, even the civil servants in the study who sat a lot didn’t see their risk of mortality increase. But they also exercised a lot. The rather straightforward conclusion: sitting a lot might not be bad as long as it is accompanied by exercise when one is not sitting.
“This is a very good study but it is based on highly active people,” said John Buckley, one of the authors of a health experts’ consensus statement that suggested office workers should aim for at least two hours of standing and light walking during an eight-hour work day. “What you can draw from this is that people who are highly active don’t have to worry about their sedentary behavior,” Buckley told Quartz.
Other research unsurprisingly shows that being less sedentary is good for your body. A study published last year in the British Journal of Sports Medicine studied the impact of sedentary behavior on telomere length—telomeres are the caps on the end of DNA strands that shorten with factors including age, illness, and obesity; telomere length has been associated with longevity. Between two groups of elderly, overweight subjects, the group that sat the least saw their telomeres grow. “Their cells seemed to be growing physiologically younger,” the New York Times reported at the time. In this case, exercise did not seem to have a significant impact—simply sitting less appeared to foster healthier cells.
Given all the conflicting advice, it seems the safest bet is to not sit for long stretches of time, exercise as much as possible (though not too much, because you might get hurt), and not drink six-packs of soda and eat double-cheeseburgers every day. So now you know.