Moderate exercise after altitude exposure fails to induce decompression sickness
Webb, J.T.; Pilmanis, A.A.; Fischer, M.D.
Aviation Space and Environmental Medicine 73(9): 872-875
2002
ISSN/ISBN: 0095-6562 PMID: 12234037 Document Number: 548304
Introduction: The objective of this study was to determine the effect of exercise after altitude exposure (post-exposure exercise) on subsequent altitude decompression sickness (DCS) incidence. Existing USAF prohibition of exercise following altitude chamber training exposures and interest from operational personnel prompted our evaluation of post-exposure exercise as a DCS-inducing stressor. Methods: After a 1-h resting preoxygenation, 67 subjects were exposed to 30,000 ft for 2-h while performing mild, upper body exercise. The subjects were monitored for venous gas emboli (VGE) with an echo-imaging system and observed for signs and symptoms of DCS. Subjects without DCS (n=31) or with DCS which resolved during recompression (n=29) were randomly assigned to post-exposure rest (control, n=29) or moderate exercise (50% of peak oxygen uptake, dual-cycle ergometry; n=31) and both groups were monitored for delayed or recurring DCS. Results: The altitude exposure resulted in 48.3% DCS in the 60 volunteers serving as test or control subjects. Of 31 subjects assigned to the post-exposure exercise group, 15 had developed DCS which resolved during descent. No cases of DCS were observed or reported during or following post-exposure exercise. Conclusion: The results show that moderate exercise after exposure did not result in either delayed-onset or recurring DCS.