Sitting for hours on end may raise your risk of some types of cancer, even if you get exercise at other times of the day.
Researchers examined the results of 43 studies on a total of roughly four million people, nearly 69,000 of whom had been diagnosed with cancer. The risk of colon cancer was 54 percent higher for those who spent the most (versus those who spent the least) time sitting while watching TV and 24 percent higher for those who spent the most time sitting at work or sitting throughout the day. The risk of uterine cancer was 66 percent higher for those who spent the most time sitting while watching TV and 32 percent higher for those who spent the most time sitting throughout the day. And those percentages were independent of how much exercise the participants did.
Sitting for long periods wasn’t linked to cancers of the breast, rectum, ovaries, prostate, stomach, esophagus, testes, or kidney, or to non-Hodgkin lymphoma.
What to do: These types of studies can’t prove that sitting for long stretches increases the risk of cancer. Still, it’s worth getting up from your chair and moving around or at least standing up every so often, regardless of how much time you spend exercising at other times of the day. The American College of Sports Medicine recommends “interspersing frequent, short bouts of standing and physical activity between periods of sedentary activity, even in physically active adults.”
Source: J. Natl. Cancer Inst. 106: dju098, dju135, 2014.