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Record Details

Record 18 of 1748
Exercise Versus +Gz Acceleration Training
Author and Affiliation:
Greenleaf, John E.(NASA Ames Research Center, Moffett Field, CA United States)
Simonson, S. R.(NASA Ames Research Center, Moffett Field, CA United States)
Stocks, J. M.(NASA Ames Research Center, Moffett Field, CA United States)
Evans, J. M.(NASA Ames Research Center, Moffett Field, CA United States)
Knapp, C. F.(NASA Ames Research Center, Moffett Field, CA United States)
Dalton, Bonnie P. [Technical Monitor]
Abstract: Decreased working capacity and "orthostatic" intolerance are two major problems for astronauts during and after landing from spaceflight in a return vehicle. The purpose was to test the hypotheses that (1) supine-passive-acceleration training, supine-interval-exercise plus acceleration training, and supine exercise plus acceleration training will improve orthostatic tolerance (OT) in ambulatory men; and that (2) addition of aerobic exercise conditioning will not influence this enhanced OT from that of passive-acceleration training. Seven untrained men (24-38 yr) underwent 3 training regimens (30 min/d x 5d/wk x 3wk on the human-powered centrifuge - HPC): (a) Passive acceleration (alternating +1.0 Gz to 50% Gzmax); (b) Exercise acceleration (alternating 40% - 90% V02max leg cycle exercise plus 50% of HPCmax acceleration); and (c) Combined intermittent exercise-acceleration at 40% to 90% HPCmax. Maximal supine exercise workloads increased (P < 0.05) by 8.3% with Passive, by 12.6% with Exercise, and by 15.4% with Combined; but maximal V02 and HR were unchanged in all groups. Maximal endurance (time to cessation) was unchanged with Passive, but increased (P < 0.05) with Exercise and Combined. Resting pre-tilt HR was elevated by 12.9% (P < 0.05) only after Passive training, suggesting that exercise training attenuated this HR response. All resting pre-tilt blood pressures (SBP, DBP, MAP) were not different pre- vs. post-training. Post-training tilt-tolerance time and HR were increased (P < 0.05) only with Passive training by 37.8% and by 29.1%, respectively. Thus, addition of exercise training attenuated the increased Passive tilt tolerance. Resting (pre-tilt) and post-tilt cardiac R-R interval, stroke volume, end-diastolic volume, and cardiac output were all uniformly reduced (P < 0.05) while peripheral resistance was uniformly increased (P < 0.05) pre-and post-training for the three regimens indicating no effect of any training regimen on those cardiovascular variables. Plasma volume (% delta) was uniformly decreased by 8% to 14% (P < 0.05) at tilt-tolerance pre- vs. post-training for all regimens indicating no effect of these training regimens on the level of vascular fluid shifts.
Publication Date: Jan 01, 2002
Document ID:
(Acquired Oct 18, 2002)
Document Type: Preprint
Meeting Information: The 10th International Conference on Environmental Ergonomics; 23-27 Sep. 2002; Fukuoka; Japan
Contract/Grant/Task Num: NIH-UKGCRC-MOIRR02602; NIH-GRRC-MOI-RR00827; RTOP 111-10-20; RTOP 775-00-13; RTOP 635-00-04
Financial Sponsor: NASA Ames Research Center; Moffett Field, CA United States
National Inst. of Health; Bethesda, MD United States
Organization Source: NASA Ames Research Center; Moffett Field, CA United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
Availability Source: Other Sources
Availability Notes: Abstract Only
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