[hoorayimhelping]

>We exist as we do because of the pressures our environment exhibits on us (e.g. gravity)- outside of hubris I can't imagine why folks would think weightlessness would have zero impact.

Skylab 2, 3 and 4 specifically tried to study the effects of space habitation on the human body. I seem to remember reading that the later Skylab crews were considered to be in better health when they came back than when they left. Even though it was early, it could explain the dismissiveness. The data at the time might have made it seem that we'd figured it out already.