A new word has been coined to describe a prevailing modern lifestyle condition - sedentarism. And as Peter Dingle PhD points out it’s easy to overcome. Just get up and move. Sitting for any length of time may not be good for us. More and more evidence shows that sedentary behaviours including sitting, watching television, using a computer, and driving a car are risk factors, independent of physical activity, for adverse chronic disease in adults such as obesity, cancer, heart and kidney disease, chronic neck and back pain, as well as premature death.
The act of sitting increases your chances of developing all these conditions independent of how much exercise you do and how active you are outside of sitting. You can do a long run every night, but if you sit too long during the day you still increase your risk of these chronic conditions. Unfortunately, people have grown more sedentary during the 20th and 21st centuries. On average, adults spend an average of eight hours per day sitting, increasing to 10 or more hours a day in older age and young people between the age of six and 20 spend on average 40 to 60% of the day sitting, often in prolonged and uninterrupted bouts (1). In Australia, at least according to the ABS, we sit for around 39 hours a week and on average 10 hours at work. But these are average figures - clerical and administration workers have an average of 22 hours sitting at work. Apparently we sit for 13 hours a week in front of television and, in front of a computer for non-work related activities, eight to 24 year olds sit for nine hours a week. Remember, these are just averages and as I don’t sit down much (I use a standing desk) someone is sitting a lot more than average. Also however, people who tend to sit at work also tend to sit more in other locations, adding to the increased burden of sitting.
Cancer Risk
Studies have linked sitting to a greater risk for colon, prostate, breast and endometrial cancers. In a review of 18 studies, 10 found statistically significant, positive associations between sedentary behaviour and cancer outcomes. Sedentary behaviour was associated with increased colorectal, endometrial, ovarian, and prostate cancer risk; cancer mortality in women; and weight gain in colorectal cancer survivors (2). In a study of 5380 women and 5788 men, a standing/walking occupation was associated with a 32% lower risk of all-cause mortality and a 40% risk reduction in cancer mortality, compared to sitting occupations. Too much sitting is also associated with cancer survival. Sitting is associated with weight gain around the waist, insulin resistance, and markers of inflammation, which may contribute to adverse cancer outcomes (disease progression, recurrence, or death) and to the development of other chronic disease. The daily sedentary time was correlated with the protein levels of inflammatory biomarkers (3,4,5),which is associated with cancer incidence and survival. Initial studies indicate that cancer survivors spend two thirds of their waking hours sitting (6).
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