Citation

Balldin U, O'connor R, Isdahl W, Werchan P, Morgan T. SAFE J. 2003; 31(1): 13-19.

Affiliation

Life Sciences, Wyle Laboratories, Inc., Brooks AFB, TX, United States

Copyright

(Copyright © 2003, SAFE Association)

DOI

unavailable

PMID

unavailable

Abstract

This study compared the impact of heat stress on G-tolerance for four different USAF anti-G systems. Six subjects completed four trials each, wearing the standard CSU-13B/P anti-G suit (STD), COMBAT EDGE (CE), the Advanced Technology Anti-G Suit (ATAGS), or CE with ATAGS. The thermal stress consisted of walking for 20 minutes on a treadmill in a chamber heated to 35 degrees C, with radiant heat and 85% relative humidity. G-tolerance and flight simulation tracking performance were registered in a centrifuge. Heat stress caused significant rectal and skin temperature elevations, weight loss and increases in hemoglobin and hematocrit, but there were no physiologically significant differences between the four equipments. Maximal attained relaxed G-loads with gradual and rapid onset were highest with CE/ATAGS and lowest with STD both before and after heat stress. During rapid onset G-profiles that permitted subjects to strain if needed, heart rate was significantly lower with ATAGS and CE/ATAGS. Flight simulation tracking scores during closed loop G-exposures after thermal stress were significantly better with ATAGS and CE/ATAGS in RMS (deviations from the target) and time on target. Thus, the CE/ATAGS combination appeared to provide the best G-protection and performance task scores both before and after heat stress.