Too much sitting is bad for you, we all know that. It causes obesity, heart disease and now, researchers have found a link between too much sitting and some forms of cancer.
In a study published in the Journal of the National Cancer Institute, researchers report that people who spend more hours of the day sitting have up to a 66% higher risk of developing certain types of cancer than those who aren’t as sedentary.
These results go beyond the advice by most health professionals for everyone to become more physically active. In reviewing 43 studies in which volunteers were asked about their daily activities and their cancer incidence, the investigators found that the link between sitting and cancer remained strong no matter how physically active the participants were. In other words, even people who worked out regularly but who spent more hours on the couch watching TV, for instance, showed higher rates of cancer than those who didn’t sit as much.
Sedentary behavior was associated with a 24% greater risk of developing colon cancer, a 32% higher risk of endometrial cancer, and a 21% increased risk of lung cancer. When the researchers delved deeper into different types of sedentary habits, they found that watching TV was linked to a 54% higher risk of colon cancer and a 66% greater risk of endometrial cancer. For every additional two hours that participants spent sitting during the day, their risk of colon cancer rose by 8%, and their risk of endometrial cancer went up by 10%. They didn’t find a link between sedentary behavior and other types of cancer, including breast, prostate, and non-Hodgkin lymphoma.
The findings, says Dr. Graham Colditz, of Washington University School of Medicine, who wrote an editorial accompanying the study, highlight the difference between being physically active and being sedentary. It’s not enough to just be active—it’s also important to sit less. But most public health messages aren’t stressing the distinction. “People are not talking about sitting time in the same way as physical activity,” he says. “Guidelines say limit the time spent sitting without drilling into how long or what types of sitting they are talking about.”
