Pharmacological Countermeasures for High Altitude

This study will use a double-blind randomized study design in which one group will receive erythropoietin and the other a placebo (saline) for 4 weeks, then both groups will receive acetazolamide. Eighteen men and women volunteers will complete 5 study phases: Phase 1) two week sea level baseline testing (orientation, two VO2peak assessments, three 3.2 km treadmill time-trial, assessment of resting ventilation, venipuncture and capillary blood collection, and Hbmass assessment), and a VO2peak and 3.2 km treadmill time-trial moderate altitude (3,000 m); Phase 2) 4 week intervention to receive subcutaneously erythropoietin or placebo. The erythropoietin (Procrit) dosing regimen will consist of 50 IU/kg three times a week (M-W-F); Phase 3) a second moderate altitude exposure (VO2peak and 3.2 km treadmill time-trial with acetazolamide administered (orally; 250 mg b.i.d) for 3 1/2 nights starting the day before the altitude exposure; Phase 4) high altitude acclimatization in which volunteers will reside for 15 days at 4,300 m altitude (Pikes Peak, Colorado Springs) completing multiple VO2peak assessments and 3.2 km treadmill time-trials, resting ventilation, venipuncture and capillary blood collection; and Phase 5) deacclimatization phase to assess changes in hematological biomarkers after returning from Pikes Peak. This study consists of 41 visits over a \~10 week time period. Visits will take place in Natick, MA and the Pikes Peak High Altitude Research Laboratory at Colorado Springs. Additional assessments that will be completed multiple times during the study include: acute mountain sickness questionnaire, lung gas diffusion at rest and during exercise, oxygen saturation, arterialized blood gases (PO2, PCO2, pH, HCO3) and heart rate during rest, exercise, and sleep, and muscle tissue oxygenation. The primary outcome is 3.2 km treadmill time-trial performance. Secondary outcomes include: incidence and severity of acute mountain sickness, ventilation and gas exchange, Hbmass, Hb concentration, Hct, arterialized blood gases, lung diffusion at rest and during exercise, oxygen saturation and heart rate during rest, exercise, and sleep.