A large number of patients with underlying pulmonary disease travel by air each year and are therefore at risk for significant cardiopulmonary effects of induced hypoxia at higher altitudes. The hypoxia altitude simulation test provides a simple way to identify those patients at risk by simulating conditions encountered at high altitude. By asking the patient to breathe a mixture of gases with an oxygen saturation of 15.1%, the test simulates a cabin pressure of 8,000 feet and allows the physician to screen for hypoxia, significant symptoms, and arrhythmias. Repeating the test with supplemental oxygen ensure adequate treatment of those patients who have a decrease in the alveolar pressure of oxygen, significant symptoms, and/or arrhythmias.