Colorado-Oregon Altitude Study

Inclusion Criteria: * Ages 18 to 40 Recreational athletes able to pass the APFTs Men and women of any ethnic background Medical and dental insurance Able to read and speak English Fully vaccinated against COVID-19 * If a subject is taking medication that is deemed safe and will not interfere with the main outcome measurements of the study as determined by clinical research staff, they will be included. * If a subject had a previous mild to moderate COVID-19 infection but is deemed safe for all research activities by clinical research staff, then they will be included in the study. Exclusion Criteria: * Smokers Previous severe COVID infection or contraction of any COVID infection occurring during the study. Previous mild to moderate COVID infections will be considered for the study on a case-by-case basis as determined safe by clinical research staff (see inclusion criteria). Carboxyhemoglobin values (HbCO) 3% or greater at baseline Diseases or disorders known to be affected by hypoxia or the drugs used in this study, including but not limited to hypotension, anemia, sickle cell trait or disease, and diabetes. Anyone unable to receive the investigational drugs used in this protocol (EPO or iron). Those with a history of significant head injury, migraines or seizures. Anyone that is pregnant or trying to become pregnant. Any medication determined by the clinical research staff to be unsafe or to interfere with the outcome measurements of the study. Those with inability to be headache-free when consuming the amount of caffeine in two six-ounce cups of coffee or less per day. Extended exposure (\>6 hours) to high altitude above 1000m in the month leading up to departure to Colorado. Those who have been on an airline flight over six hours (the lowered cabin pressure for an extended period of time approximates exposure to high altitude) within the month leading up to departure to Colorado. Those who are unable to achieve the minimum physical criteria as outlined above. Anyone with lung function below the lower limit of normal per GLI standards. Previous diagnosis of high altitude pulmonary edema or high altitude cerebral edema upon altitude exposure. Failure to get fully vaccinated against COVID-19. Choosing not to be vaccinated will result in exclusion. Family history of clotting disorders, anemia or venous thrombosis. Plans for professional competition during or within 1 week after participation in this study as participation may enhance your aerobic performance Presence or absence of a PFO once we have enrolled a sufficient number of each group representation in the general population (e.g., \~40% of population has a PFO and \~60% does not). However, all subjects will be allowed to complete all baseline screening to assure that we will have enough subjects to go to Colorado Biological sex once we have enrolled a sufficient number of males and/or females as we are aiming to enroll \~50% of each sex. However, all subjects will be allowed to complete all baseline screening to assure that we will have enough subjects to go to Colorado. Subjects will be excluded from telemetric pill ONLY if they have a history of obstructive diseases of the gastrointestinal tract including diverticulosis, diverticulitis, inflammatory bowel disease, peptic ulcer disease, Crohn's disease, ulcerative colitis, or previous GI surgery.