Recovery to +1Gz and +2Gz following +Gz-induced loss of consciousness: operational considerations.

With the development of aircraft autorecovery technology, the need to understand the effects of potential inflight recovery profiles on human physiology has become important. Eight male volunteer subjects were exposed to +7Gz with an onset rate of 6 G.s-1 until they were unconscious. The subjects did not wear anti-G suits and did not perform anti-G straining maneuvers. The subjects controlled the centrifuge utilizing an F-16A stick, thereby deliberately self-inducing their unconsciousness. Following +Gz-induced loss of consciousness (G-LOC), recovery to the usual +1Gz level was compared to recovery to a +2Gz level by comparing absolute, relative, and total incapacitation times. The mean (+/- S.D.) absolute incapacitation time (period of unconsciousness) was 11.9 +/- 2.9 s for recovery to a +1Gz level and 12.9 S (+/- 6.9 S.D.) for recovery to a +2Gz level. The mean relative incapacitation time (period of confusion/disorientation) was 3.6 +/- 2.3 s for recovery to a +1Gz level as compared to 2.9 +/- 0.8 s for recovery to a +2Gz level. The total incapacitation time (sum of the absolute and relative incapacitation) was 15.6 +/- 2.7 s for recovery to a +1Gz level and 16.0 s (+/- 6.8 S.D.) for recovery to a +2Gz level. No significant differences in any of the incapacitation times were found when comparing recovery to +1Gz and +2Gz. The mean time from the onset of +Gz-stress to the onset of unconsciousness was approximately 7 s.(ABSTRACT TRUNCATED AT 250 WORDS)