THE EFFECT OF VARYING TIME AT -Gz ON SUBSEQUENT +Gz PHYSIOLOGICAL TOLERANCE (PUSH-PULL EFFECT)

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Authors
  1. Banks, R.D.
  2. Grissett, J.D.
  3. Saunders, P.L.
  4. Mateczun, A.J.
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN)
Abstract
Previous studies have demonstrated decreased +Gz tolerance when preceded by O Gz or -Gz, referred to as the "push-pull effect". The purpose of this equipment was to observe the effect of varying time duration at -Gz on the push-pull effect. Methods: During single sessions, six subjects (three men, three women) were subjected to five relaxed exposures to _2.25 Gz on the NAMRL Coriolis Acceleration Platform (CAP). The first and last exposures were control runs that were preceded by +1 Gz. Each experimental run was preceded by -2 Gz using a light bar. Results: Mean BP was significantly reduced when the +2.25 Gz exposures were preceded by -Gz. Following 15 s of -2 Gz, mean BP decreased more and was slower to recover than for 2 and 5 s of -2 Gz. Reported incidents of visual light loss were: 1 following 2 s, 2 following 5 s, and 4 following 15 s at -2 Gz. There were no reports of visual light loss during control runs. Conclusion: during relaxed conditions, the push-pull effect is augmented by increasing duration of the preceding -Gz.
Keywords
Push-pull effect;Coriolos Acceleration Platform (CAP)
Report Number
DCIEM-94-15 — Reprint
Date of publication
31 Aug 1995
Number of Pages
5
Reprinted from
Aviation, Space, and Environmental Medicine, vol 66, no 8, 1995, p 723-727
DSTKIM No
95-04960
CANDIS No
154361
Format(s):
Document Image stored on Optical Disk;Hardcopy

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