All the studies so far indicate sitting (or other forms of inactivity) are bad no matter how much you exercise at other times.
The best natural experiment was the London bus driver study which showed huge differences in heart problems between drivers (sitting all day) and conductors (standing all day). Both were drawn from the same pool of employees and randomly assigned roles, so the experiment was naturally controlled for everything except the difference in behavior.
There were some other differences such as drivers having a more stressful job and conductors having more social interactions which might explain some of the differences in outcomes apart from the sitting/moving difference. But in any case, sitting for hours a day at a stressful job with minimal social interaction is incredibly bad for your health. Programmers take note!
Interesting. It would be a bit more legitimate of if the difference was between standing and sitting bus drivers (assuming there was some way to stand and drive a bus).
Or, straight to the point, if there was a study involving standing programmer and sitting programmers... preferably one in which the roles were randomized, because I'd suspect that programmers who've already chosen to stand while they work are probably a more health-conscious lot as it is.
I can only thing of a few other differences besides sitting/standing people in this study that might make a difference. One is that I imagine the standing person absorbs the constant vibration of the bus better than the sitting person. Long term vibration is known to have deleterious effects.
I don't have access to the original paper but from the summary here http://www.epi.umn.edu/cvdepi/study.asp?id=13 it looks like the study was only observational, roles were not randomly assigned.
The best natural experiment was the London bus driver study which showed huge differences in heart problems between drivers (sitting all day) and conductors (standing all day). Both were drawn from the same pool of employees and randomly assigned roles, so the experiment was naturally controlled for everything except the difference in behavior.
There were some other differences such as drivers having a more stressful job and conductors having more social interactions which might explain some of the differences in outcomes apart from the sitting/moving difference. But in any case, sitting for hours a day at a stressful job with minimal social interaction is incredibly bad for your health. Programmers take note!