Originally Posted by
tlglenn
It's more likely in instrument conditions since you no longer have a visual reference to the outside horizon, but by the time you're ready for instrument training your body should have adapted.
I'd agree strongly with this. I've been sick many times in VMC, but never in IMC (despite some bad turbulence). Not only is the body somewhat acclimatised by the time you start your instrument rating, but IFR never (or at least should never) involves the manoeuvring and G forces found in VFR. An important principle of IFR is that manoeuvres should be smooth, gentle, and well co-ordinated to avoid disorientation.
The worst turbulence I've ever experienced was during my instrument rating checkride, and I felt fine. One second we were 50 feet above the MDA on an VOR approach, the next 20 feet below the MDA, and I though the checkride was busted right then, but the examiner was happy that I recovered immediately and returned to above the MDA!