title: The effects of exercise on bubble formation and bends susceptibility at 9,100 m (30,000 ft; 4.3 psia).
abstract: This study assessed the value of controlled exercise in a bends susceptibility test. Healthy male subjects were exposed to a pressure altitude of 9,100 m (30,000 ft; 4.3 psia) for a period not exceeding 8 h on two separate days at least 1 week apart. During one exposure, subjects performed five deep knee bends followed by five upward arm extensions with 5-lb weights every 15 min; during the other exposure, they remained sedentary. Exercise and no-exercise altitude exposures were randomized between subjects. A precordial Doppler monitoring technique was used to record venous bubbling at 15-min intervals. Bends was diagnosed from subjective symptoms. Results have shown that controlled exercise decreases time to maximum venous bubbling and increases the incidence of Grade 2 bends compared to no-exercise conditions. Exercise also appears to increase the validity of precordial Doppler monitoring as a method to predict bends onset.
authors: Technology, Inc., Life Sciences Division, San Antonio, TX 78216.
authors: R W
authors: RW
authors: Krutz
authors: G A
authors: GA
authors: Dixon
mesh_terms: D000328:Adult; D000531:Altitude; D001274:Atmospheric Pressure; D003665:Decompression Sickness / Q000097:blood / Q000209:etiology*; D006801:Humans; D008297:Male; D005082:Physical Exertion; D012307:Risk Factors