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Dual-cycle ergometry as an exercise modality during prebreathe with 100 percent oxygenIn an effort to reduce prebreathe time requirements prior to extravehicular activities and high-altitude flights, a combined arm and leg exercise task proposes to enhance denitrogenation by incorporation of both upper and lower body musculature at a moderately high work intensity during prebreathe with 100% oxygen. Preliminary findings indicated peak oxygen consumption (VO2peak) levels attained on the dual-cycle ergometer do not differ significantly from those levels attained on the treadmill. Eight male subjects were exercised to VO2peak using leg-only cycle ergometry and dual-cycle ergometry on separate days. Preliminary data during dual-cycle ergometry showed arm work equaling 30% of the leg workrate at each stage of the incremental test resulted in arm fatigue in several subjects and a reduced VO2peak compared to dual-cycle ergometry with arm work at 20%. Thus, the 20% workrate was used during the dual-cycle VO2peak trial. On a third experimental day, subjects performed a 10 minute exercise test at a workrate required to elicit 75% of VO2peak for each subject on the dual-cycle ergometer. Blood lactate response to the exercise was monitored as an objective measure of fatigue. Peak VO2 levels attained on the leg-only and the dual-cycle ergometry tasks were not significantly different. Blood lactate levels were significantly elevated following the dual-cycle ergometry at 75% VO2peak. However, lactate levels show the expected rate of decline during recovery and, as demonstrated in the literature, should return to baseline levels within 30 minutes following exercise cessation. Thus, dual-cycle ergometry at 75% VO2peak appears to be a valid exercise for use during prebreathe and should not contribute to fatigue during subsequent EVA's.
Document ID
Document Type
Conference Paper
Heaps, Cristine L.
(Krug Life Sciences, Inc. San Antonio, TX, United States)
Fischer, Michele D.
(Krug Life Sciences, Inc. San Antonio, TX, United States)
Webb, James T.
(Krug Life Sciences, Inc. San Antonio, TX, United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1994
Publication Information
Publication: NASA. Johnson Space Center, Seventh Annual Workshop on Space Operations Applications and Research (SOAR 1993), Volume 2
Subject Category
Aerospace Medicine
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.

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