Efficacy of Residence at Moderate Versus Low Altitude on Reducing Acute Mountain Sickness in Men Following Rapid Ascent to 4300 m
Abstract
To determine if residence at moderate (*2000 m) compared to low (< 50 m) altitude reduces acute mountain sickness (AMS) in men during subsequent rapid ascent to a higher altitude. Nine moderate-altitude residents (MAR) and 18 sea-level residents (SLR) completed the Environmental Symptoms Questionnaire (ESQ) at their respective baseline residence and again at 12, 24, 48, and 72 h at 4300m to assess the severity and prevalence of AMS. AMS cerebral factor score (AMS-C) was calculated from the ESQ at each time point. AMS was judged to be present if AMS-C was < 0.7. Resting end-tidal CO2 (PETco2) and arterial oxygen saturation (Sao2) were assessed prior to and at 24, 48, and 72 h at 4300 m. Resting venous blood samples were collected prior to and at 72 h at 4300m to estimate plasma volume (PV) changes. MAR compared to SLR: 1) AMS severity at 4300 was lower (p < 0.05) at 12 h (0.50 + 0.69 vs. 1.48 +/- 1.28), 24 h (0.15 +/- 0.19 vs. 1.39 +/- 1.19), 48 h (0.10 +/- 0.18 vs. 1.37 +/- 1.49) and 72 h (0.08 +/- 0.12 vs. 0.69 +/- 0.70); 2) AMS prevalence at 4300 was lower ( p < 0.05) at 12 h (22% vs. 72%), 24 h (0% vs. 56%), 48 h (0% vs. 56%), and 72 h (0% vs. 45%); 3) resting Sao2 (%) was lower (p < 0.05) at baseline (95 +/- 1 vs. 99 + 1) but higher (p < 0.05) at 4300 at 24 h (86 +/- 2 vs. 81 +/- 5), 48 h (88 +/- 3 vs. 83 +/- 6), and 72 h (88 +/- 2 vs. 83 +/- 5); and 4) PV (%) did not differ at 72 h at 4300m in the MAR (4.5 + 6.7) but was reduced for the SLR (-8.1 +/- 10.4). These results suggest that ventilatory and hematological acclimatization acquired while living at moderate altitude, as indicated by a higher resting Sao2 and no reduction in PV during exposure to a higher altitude, is associated with greatly reduced AMS after rapid ascent to high altitude.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2013
- Accession Number
- ADA578609
Entities
People
- Allen Cymerman
- Beth A. Beidleman
- Charles S. Fulco
- Janet E. Staab
- Paul B. Rock
- Stephen R. Muza
Organizations
- United States Army Research Institute of Environmental Medicine