[The duration of tolerance to positive acceleration].

p R E V I O U S studies of positive g (headward acceleration) 'have concerned, principally, exposure of the seated subject to forces generally limited to a few seconds in du,ration. Beyond this limit in time there is an area of acceleration tolerance remaining virtually unexplored, particularly that area involving accelerations of sub-blackout magnitude. The forces encountered in existing high performance vehicles as well as those anticipated in future rocket-propelled systems made imperative this investigation of man's ability to withstand low magnitude positive accelerations applied over relatively long periods of time.