Just like a month ago there was a study showing that no amount of quick walks could offset a day of sitting.
Science is built upon a foundation of falsifiability. The pinnacle of understanding in science is an accepted theory which can, of course, be discarded if significant evidence to the contrary comes to light.
This wouldn't be much different from any other process. And, of course, could call into question many other things we have fixed times in the day for.
I'm actually struggling to imagine sitting 12 hours a day and also getting real exercise in. Unless they don't count walking around the house to eat and such, that is a crap load of sitting.