Morgans wrote:

snip


My theory is that it all goes back to will controlling the sensations. While
you were doing the acro, you were no doubt concentrating on not being sick.
Afterward, you relaxed, and the disorientation done before finally did it's
work.

I have my own sailing story that says much the same thing.

I was racing in a 16 foot Albacore on Lake Ontario and we had been
bouncing around all morning during the first race with no ill effects.
Then they called a lunch break while we basically bobbed around and
nibbled a bit. Both I and the fellow with me were very queasy, although
we did managed to hold lunch down... barely. At the start of the next
race we were focussed on lining up and sailing for the line and we both
felt better. However, the start was called back, and during the 20
minutes before the next one we were both queasy again.

I am prone to motion sickness, and the best thing I have found is to
get my mind as far out of the vehicle as possible.

John Halpenny