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+3Gz tolerance in aerobically-trained and sedentary men after Shuttle flight simulation.

Goldwater DJ, Convertino VA.

Aviat Space Environ Med. 1988 May; 59: 485.

NASA-Ames Research Center, Moffett Field, CA, USA.

Thirteen men giving a history of regular aerobic training (AT) (VO2 max 47.4 +/- 1.6 ml/kg min) were compared to 8 age-matched (35 to 50 y.o.) sedentary controls (S) (VO2 max 35.2 +/- 1.5) to assess +Gz tolerance (GTOL) analogous to, although more intense than, Shuttle re-entry stress. Subjects went to greyout at +3 Gz pre- and post- 6 days of head-down (-6 degrees) bedrest (BR). PreBR GTOL for AT was 372 sec vs 537 for S (ns). PostBR decrease in GTOL was different (p < .05) for AT: -259 sec (-68%, p < .01) vs S: -165 sec (-35%, ns). PreBR resting (R) heart rates (HR) were lower (p < .05) in AT (63 bpm) than S(72). PostBR, resting HR of AT increased 13% (p < .01); S HR's were unchanged. PreBR HR increase from R to peak 3 G was much larger (p < .05) in AT (+90%, P < .01) than in S (+63%, p < .01). After BR, 3 Gz increased HR similarly (mean +85%, p < .01) in both groups. Resting diastolic pressures (DBP) were lower (p < .05) in AT (54 mmHg) than S (63) preBR as well as postBR, whereas systolic BPs were similar in both groups. After BR, deconditioned AT had + 3 Gz HR and BP responses, from rest to peak 3G, similar to S. Nevertheless, the decrease in GTOL postBR was larger in AT. PreBR plasma volume (PV, ml/kg) was inversely correlated with BR GTOL (r = -.64, p < .01). BR decreases in PV were correlated with low BR GTOL (r = .63, p < .01) and with preBR VO2 max (r = .42, 1p < .05). Aerobic training may be associated with greater +Gz intolerance in spaceflight participants after weightlessness exposure in the absence of countermeasures.

Publication Types:
  • Meeting Abstracts
Keywords:
  • Bed Rest
  • Blood Pressure
  • Case-Control Studies
  • Heart Rate
  • Humans
  • Immune Tolerance
  • Male
  • Plasma Volume
  • Rest
  • Space Flight
  • Weightlessness
  • education
  • immunology
  • NASA Center ARC
  • NASA Center KSC
  • NASA Discipline Cardiopulmonary
  • NASA Discipline Number 21-10
  • NASA Program Biomedical Research
Other ID:
  • 95608668
UI: 102212930

From Meeting Abstracts




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