The bizarre and incompetent advice from medical academics never stops coming.
They are the people who said that Vioxx was the best drug for elderly, dehydrated people with broken hips.
They are the people who told you to eat vegetable oils that at the time were full of unlabelled trans-fats.
They are the ones who say that the solution to a high blood sugar is to eat more carbohydrate.
This is the profession that prescribes antidepressants to 1 in 10 Australians, one of the highest rates in the world.
And they are the people who say I should work standing up.
I'm not going to point out the obvious mathematical inadequacy of the original research on which that advice was based. (unless someone pays me to do so) Most doctors only read the abstract of such research, so couldn't tell.
Suffice it to say that if you don't include all confounding factors in such a study, you can prove just about anything. And if you parametrise activity in time units, you are not going to get the right answer. An hour spent chatting and stretching at the gym does not expend nearly as much energy as the hour I spent racing in the mountain run yesterday.
Lets look at the research that better adjusts for the problem of confounding.
First, there was the Whitehall II study. More than 80,000 person-years of follow-up and 450 deaths, showed NO effect of sitting on mortality. It also pointed out inadequacies of previous research and chided policy makers for over-interpretation of poorly controlled research.
More recent research (doi: 10.1186/s12966-016-0349-y) showed a trend towards better health outcomes people who sit at work, even after allowance for income/SES differences. Of course that does not prove that sitting is better, for the same reason of inadequate adjustment of confounding, but makes it unlikely that it is worse.
So don't just do something, sit there.