If you’re sitting down as you read this, you may be slowly killing yourself. Sounds harsh, but it’s true: Sitting for six hours or more can increase your risk of dying from major diseases, including cancer.
The evidence has been growing for a few years now, with the most recent coming this past summer from the ongoing American Cancer Society’s Cancer Prevention Study II (CPS II). And it seems women are at higher risk: Thirty-seven percent face a greater chance of death compared to those who spend less than three hours on their tushes.
This new finding adds fuel to the recent analysis from the University Health Network in Toronto that looked at 47 studies examining the relationship between sitting and mortality. The findings concluded that people who sit too much every day are at an increased risk of diabetes, heart disease, cancer and shorter life spans ‘ even if they exercise.
It’s not only sitting at a desk but also lounging in front of the TV that can lead to major health risks. In 2010, the Australian Diabetes, Obesity and Lifestyle Study, which followed subjects for an average of just over six years, found that death rates were significantly higher for adults who spent more time watching TV. This was the first study to link viewing time with mortality. Results showed that every hour spent sitting in front of the TV can increase your risk of dying earlier ‘ by 11 percent for all causes of death, by 18 percent for cardiovascular death and by nine percent for cancer death.
The ‘Sitting Disease’
When you sit for long periods, your muscles aren’t contracting, which disrupts blood flow, according to David Dunstan, co-author of the 2010 Australian study.
‘Adults who sit or lie down for several hours at a stretch experience big reductions in insulin sensitivity and glucose tolerance, as well as increased amounts of fat in their blood,’ adds Travis Saunders, a certified exercise physiologist and PhD graduate from the University of Ottawa who studies the health impact of sedentary behaviour. Those changes can cause Type 2 diabetes. And once that develops, it greatly increases the risk of blood clots or heart attack. As well, when you sit for long periods of time without taking a break to get up and walk around, a protein called fibrinogen increases. It’s the major risk factor for deep vein thrombosis and cardiovascular disease.
As for the link to cancer, Christine Friedenreich, a research scientist with Alberta Health Services, says that, while studies connecting sedentary behaviour and cancer are in their infancy, increased activity has been shown to reduce C-reactive protein. This biomarker, when elevated, puts people at higher risk for certain cancers, such as breast and colon cancers. Right now, most research has simply shown that increased physical activity can greatly reduce people’s risk of cancer, but it hasn’t honed in directly on the negative effects of sitting for too long.
However, the new CPS II shows that a distinct connection between the two is emerging, noting that people who sit for great lengths of time and don’t exercise regularly face even greater mortality rates than those who just sit ‘ a startling 94 percent higher for women and 48 percent higher for men.
Stand Up For Yourself
Mark Tremblay, founder of the Sedentary Behaviour Research Network and director of the Healthy Active Living and Obesity Research Group at the Children’s Hospital of Eastern Ontario Research Institute, recommends a combination of standing, sitting and taking breaks. ‘A sit-stand combination is actually better than just sitting or just standing,’ he says. ‘If you stand too long, your back will get sore, blood will pool in your feet and you’ll feel lightheaded.’
The 2010 Australian study suggests that overweight and obese adults can lower their glucose and insulin levels after a meal by taking a break involving light- to moderate-intensity walking. ‘Even among healthy adults, activity breaks throughout the day ‘ for example, two-minute walks every 20 minutes ‘ are good for you and even necessary,’ explains Dunstan.