Rapid Acclimatization to Hypoxia at Altitude

Inclusion Criteria: * normotensive (i.e. \<140/90 mmHg) Exclusion Criteria: * Pregnancy * nursing mother * current tobacco use or regular use within the previous two years * use of prescription medication other than birth control * asthma or any other type of lung/respiratory dysfunction * resting oxygen saturation \<95% * unwillingness to abstain from exercise for 48 hours prior to laboratory testing * use of anticoagulant therapy or have a known or suspected bleeding disorder * identification of contraindication during screening (i.e. positive stress test) * any history of mountain sickness (altitude sickness) * any history of allergic reaction, hypersensitivity or idiosyncratic reaction to any of the products administered during the study, including allergy to any sulfa or sulfonamide derivatives * history of clinically significant illness within 4 weeks prior to Day 1 * Subjects who have made any significant donation (including plasma) or have had a significant loss of blood within 30 days prior to visit 1 * receipt of a transfusion or any blood products within 30 days prior to visit 1.