Physiological equivalence of normobaric and hypobaric exposures of humans to 25,000 feet (7620 m).

Introduction: Skepticism exists about whether normobaric and hypobaric hypoxic exposures are equivalent. We have evaluated if physiological differences between the two environments would translate into actual differences in hypoxia symptoms.

Methods: We exposed 20 subjects to 5-min 25,000-ft (7620-m) equivalent environments in an altitude chami ber and then in a ground-level portable reduced-oxygen training enclosure (PROTE).

Accommodation of females in the high-G environment: the USAF Female Acceleration Tolerance Enhancement (FATE) Project.

Background: In 1993, the U.S. Secretary of Defense opened combat aircraft assignments to women.

Pressurized sleeves and gloves for protection against acceleration-induced arm pain.

Background: Acceleration (or G) induced arm pain may develop in centrifuge runs and in flight with low arm position and assisted pressure breathing during G (PBG) in combination with an extended coverage anti-G suit. To decrease this arm pain, pressurized sleeves and gloves were developed.

Methods: Eight subjects who earlier exhibited G-induced arm pain were tested on the centrifuge.

Differences between syncope resulting from rapid onset acceleration and orthostatic stress.

Background And Hypothesis: Orthostatically-induced syncope is accompanied by venous pooling and vasodilatation. Loss of consciousness during head-to-foot acceleration (G-LOC) in aviators may be caused by a different mechanism, as venous pooling should be prevented through the use of an anti-G suit. This research was conducted to test the hypothesis that in individuals wearing a well-fitted anti-G garment, no important changes occur in the volume of dependent regions during loss of consciousness resulting from rapid onset acceleration stress.

Human tolerance to aerial combat maneuvers.

An acceleration profile was developed on the USAF School of Aerospace Medicine's 6.1-m radius centrifuge to measure human tolerance to the Aerial Combat Maneuver (ACM). The ACM profile is a continuous repetitive, 4.

Evaluation of assisted positive pressure breathing on +Gz tolerance.

The effect of both assisted and unassisted positive pressure (PPB) breathing on +Gz tolerance was evaluated. A GOR (gradual onset rate = 0.1 G/s) acceleration profile was used to evaluate five different experimental conditions: 1) G-suit-only, 2) G suit + unassisted PPB, 3) G suit + PPB assisted by the English jerkin, 4) G suit + PPB assisted by the Canadian waistcoat, and 5) the Swedish counterpressure garment G suit combination.