Effect of Six Days of Staging on Physiologic Adjustments and Acute Mountain Sickness During Ascent to 4300 Meters
ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA THERMAL AND MOUNTAIN MEDICINE DIVISION
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This study determined the effectiveness of 6 days d of staging at 2200m on physiologic adjustments and acute mountain sickness AMS during rapid, high-risk ascent to 4300m. Eleven sea-level SL resident men means SD 213 yr 7813 kg completed resting measures of end-tidal CO2 Petco2, arterial oxygen saturation Sao2, heart rate HR, and mean arterial pressure MAP at SL and within 1 h of exposure to 4300m in a hypobaric chamber prior to 6 d of staging at 2200m preSTG and on the summit of Pikes Peak following 6 d of staging at 2200m postSTG. Immediately following resting ventilation measures, all performed submaximal exercise 55 of altitude-specific maximal oxygen uptake for 2 h on a bicycle ergometer to induce higher levels of AMS. AMS-C, calculated from the Environmental Symptoms Questionnaire, was measured following 4 h and 8 h of exposure at preSTG and postSTG, and the mean was calculated. Resting Petco2 mmHg was unchanged from SL 39.82.6 to preSTG 39.33.0, but decreased p0.05 from preSTG to postSTG 32.82.6. Resting Sao2 decreased p0.05 from SL 972 to preSTG 804 and increased p0.05 from preSTG to postSTG 833. Resting HR bpm and MAP mmHg did not change in any of the test conditions. The incidence and severity of AMS-C decreased p0.05 from preSTG 9130 1.050.56 to postSTG 4553 0.590.43, respectively. These results suggest that modest physiologic adjustments induced by staging for 6 d at 2200m reduced the incidence and severity of AMS during rapid, high-risk ascent to 4300 m.
- Medicine and Medical Research