Dr. Benjamin Levine is the Medical Director of the Institute for Exercise and Environmental Medicine (IEEM), which is one of the largest human physiology research programs in the country. The IEEM has hyperbaric chambers and other equipment for conducting cardiovascular, respiratory, and neuromuscular research on how altitude, heat, and stress affect the body. In this photo, Dr. Levine talks to fellow IEEM researchers as he tests a subject in a lower body negative pressure chamber.