These reports have an empiricist slant to them and there's usually no attempt to explain the result. No doubt there's truth to be found here, but note that mere

These reports have an empiricist slant to them and there's usually no attempt to explain the result. No doubt there's truth to be found here, but note that mere act of sitting cannot be bad for health, otherwise seated meditation would be bad for health too (which it isn't). I conjecture it is the combination of sitting and hard focus on work or video games which is relevant. The brain withdraws attention from the body (which, being supported, isn't required much beyond breathing and digestion). The result seems to be bad things like inflammation, poor lymph circulation, etc, though I think this isn't understood. I remember it was said that, a few decades back in the UK, bus drivers (seated) had more heart attacks than bus conductors (standing).