Sedentary Behaviour and Endometrial Cancer.......

http://www.nature.com/bjc/journal/v103/n7/full/6605902a.html

"Our data, and that of others (Friberg et al, 2006; Patel et al, 2008), suggest that sitting time contributes to endometrial cancer risk, independent from one's participation in MVPA. We earlier estimated that as many as 22% of endometrial cancers could be avoided if women exercised vigorously five or more times per week. However, if all women had both exercised at this level and sat for 4 or fewer hours per day, then 34% of endometrial cancers could have been avoided. Thus, the incremental contribution of sedentary behaviours to the population level burden of endometrial cancer risk may be substantial."

One more reason to get up and get moving  whatever your choice is - just do it!