wrote:
It really depends on the individual. Almost anyone can tolerate 2Gs for a
sustained period but moving about or lifting anything heavy would be
difficult. I think that the cutoff point for the average person (sustained)
is around 3.5Gs.

Cub Driver wrote:
A young pilot in good physical condition ought to tolerate 5 Gs. With
specialized training, as was given to Spitfire pilots in WWII, 9 Gs is
possible.

Gotta disagree with you Dan.
happydog has it right.
G-tolerance is something you develope, you cannot just strain at the
right time and stay awake.
Back when I was younger and in excellent physical condition, I did
aerobatic training. Sustained or repeated G's will quickly drain you
with each successive maneuver. I never did enough to go to sleep, but
repeated 4-5 G maneuver's caused be to gray out for several seconds (the
instructor was then in control of the aircraft).