Accession Number:

ADA426858

Title:

Enhancement of Preoxygenation for Decompression Sickness Protection: Effect of Exercise Duration

Descriptive Note:

Journal article, Jul 1995-Oct 1999

Corporate Author:

WYLE LABS LIFE SCIENCES AND SERVICES INC SAN ANTONIO TX

Report Date:

2002-12-01

Pagination or Media Count:

7.0

Abstract:

Since strenuous exercise for 10 during preoxygenation was shown to provide better protection from decompression sickness DCS incidence than resting preoxygenation, a logical question was would a longer period of strenuous exercise improve protection even further. Increased strenuous exercise duration during preoxygenation increases DCS protection. There were y0 subjects, 30 men and 30 women, who were exposed to 9,144 m 4.3 psia for 4-h while performing mild, upper body exercise. Before the exposures, each subject performed 3 preoxygenation profiles on different days in balanced order a 90-min resting preoxygenation control a 240-min resting preoxygenation control and a 90-min preoxygenation including exercise during the first 15 min. The subjects were monitored at altitude for venous gas emboli VGE with an echo-imaging system and observed for signs and symptoms of DCS. There were no significant differences in occurrence of DCS following any of the 3 preoxygenation procedures. Results were also comparable to an earlier report of 42 DCS with a 60-min preoxygenation including a 10-min exercise. There was no difference between VGE incidence in the comparison of protection offered by a 90-min preoxygenation with or without 15 min of strenuous exercise. The DCS incidence following a 240-min resting preoxygenation, 40, was higher than observed during NASA studies and nearly identical with the earlier 42 DCS after a 60-min preoxygenation including exercise during the first 10 min. Conclusion The protection offered by a 10 min exercise in a 60-min preoxygenation was not increased with extension of the preoxygenation exercise period to 15 min in a 90-min reoxygenation, indicating an upper time limit to the beneficial effects of strenuous exercise.

Subject Categories:

  • Stress Physiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE