Laying flat on his back with no activity to perform (physical or
cognitive), without sustaining any damage

a)How many g?s can a human withstand for 1 hour? Recovery Time?
b)How many g?s can a human withstand for 1 hour and fully recover in
less than 1 minute?
c)How many g?s can a human withstand for 30 minutes and fully recover
in less than 1 minute?
d)How long can a human withstand 25 g?s?
e)Would lying in a waterbed-like device increase his endurance?

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Clarification of Question by elden-ga on 04 Jun 2004 23:47 PDT

On his back or face down or whatever postion that the most g's can be sustained

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Clarification of Question by elden-ga on 10 Jun 2004 08:29 PDT

Fron the Paper suggested by dr_bob-ga
"3. Reclined Seat....tolerance becomes progressively limited by pain
from contact with the seat, from chest compression, and from
difficulty inhaling due to the increased weight of the anterior chest
wall. These symptoms limit this technique to about 14-15 G maximum..."

It would appear that:
1) a 'waterbed', or perhaps a stiffer version of the elastipfoam that
that you see on the TV bed commercials, would reduce or eliminate the
1st problem
2) that a forced air resporator could improve the 2nd and 3rd problem.
(similar to a C-PAP machine)

Laying flat may be a bit of an issue, as most g-force machines use
centrifugal force to induce the g-forces.  Thus I'm not sure if you'll
be able to get a good answer.

While sitting, the principal cause of damage is lack of blood supply
to the brain.  Fighter Pilots typically wear a G-suit that consists of
a set of pressure coils(filled with gas or liquid) that constrict the
body(and blood vessels) in the legs, thus keeping blood supply to the
brain.

6 g's is pretty grumpy, 10 is downright evil, 25 methinks would hurt a lot.

Such a waterbed device would likely keep someone from going "squish"
at 25 G's maybe a little.

This page has some useful info:

http://www.vnh.org/FSManual/02/02SustainedAcceleration.html

This was a good article too:

"By 1958, these studies had revealed that humans have the potential to
withstand 46 G and a force of 10,000 pounds for a quarter of a second,
forces that were well in excess of those anticipated for
spaceflight.19"

http://www.vnh.org/FSManual/02/02SustainedAcceleration.html

A waterbed will only cushion sudden changes in g-force (by deforming
to allow the body to essentially accelerate slower than the maximum
instantaneous acceleration) - sort of like a shock absorber - it will
take a little bump without a problem, but if you drive off a cliff it
really doesn't matter what kind of shocks you have.