This report examined the interactive effects induced by exposure to altitude and carbon monoxide. Dr. Horvath and colleagues exposed 23 healthy young human volunteers living at sea level to concentrations of 0, 50, 100, or 150 ppm carbon monoxide in a hyperbaric chamber simulating altitudes of 55, 1,524, 2,134, or 3, 048 meters above sea level. Maximal aerobic capacity tests were performed under each exposure condition while respiratory and cardiac variables and blood levels of carboxyhemoglobin, hemoglobin, and lactate were monitored.
