Gravity and the Bod

We all know that spending a long time (months and more)
in weightlessness is bad for the human body. That's the
main reason most habitats are designed to rotate. Of
course, it's assumed that people living their lives at
one G will have access to low-G or zero-G whenever they
like, but that much of their day-to-day lives will be
conducted in an environment where they weigh the same as
they would on Earth.

This subject has come up on a thread at Amazon (I'm
surprised by how many people seem to believe that we
can't do much in Space until we have "gravity generators"
like in the movies and TV, and how some seem downright
hostile towards rotation). Somebody asked about
"turbine rooms," vertical wind tunnels used to simulate
skydiving. It was asked if this would feel like zero-G
and if it might let one experience what zero-G feels
like while protecting the bones from atrophy. This is
what I wrote back. Did I make any glaring errors?

I'm going to go out on a big, low gravity limb and say
"probably not." Zero-G feels the way it does because,
as Skabeebe pointed out, you're actually falling. In a
turbine room, you are not falling, you are lying down on
top of something. Just so happens it's a rush of wind.

And that "lying down" part is a problem. It has been
discovered that the negative effects of weightlessness
on muscle and bone are almost exactly like the effects of
lying down for months on end. So if you spent a year in
Space, and your days were spent in weightlessness, but
you slept in full-G (whether provided via rotation or
"gravity generators"), you would suffer as much
disability as if you had been in zero-G the whole time.

What we really, really don't know is what happens in G's
between 1 and 0. If you are on the Moon for a year, do
you suffer as much atrophy as if you'd been in orbit for
two months? If you are on the Moon for six years, do you
suffer as much as if you'd been in orbit for one year, or
does Lunar gravity have a different "low end" than
weightlessness? Do you recover faster after returning to
Earth? On the Moon, can all of this be prevented by
wearing a five hundred pound backpack?

The other thing we don't know is if spending time in both
full-G and zero-G, for a few hours at a time each day,
switching back and forth, day after day after day for
years, has any negative health effects at all.