Note that if you take a look at the study mentioned, http://bmjopen.bmj.com/content/2/4/e000828.full http://bmjopen.bmj.com/content/2/4/e000828.full you find:

Note that if you take a look at the study mentioned, http://bmjopen.bmj.com/content/2/4/e000828.full http://bmjopen.bmj.com/content/2/4/e000828.full you find: Our analysis assumes that there is a causal relationship between sedentary behaviour and mortality. So, it doesn't actually demonstrate it; it finds a correlation, and makes the assumption that there is causation. However, previous studies have shown that heavier people are more likely to choose sedentary jobs: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1008580/pdf/brjindmed00119-0013.pdf http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1008580/pdf/brji... . So in fact, the causation may go in the other direction; people who are heavier, or less healthy in other ways, may be more likely to choose sedentary jobs or sedentary lifestyles. It would be interesting to see if anyone has actually been able to demonstrate a causal effect based on changes in behavior. Does changing from a sitting desk to a standing desk actually help? I don't think that has been conclusively demonstrated.