Studying physiological responses to high and low ambient pressures, exercise and altered temperatures can be used to improve the performance of divers and climbers, but also provide insight into the response to stress in clinical medicine. The FG Hall Environmental Laboratory contains a seven-chamber 254 cu m chamber complex that can simulate diving and altitude. This unique complex is the largest civilian environmental facility in the country. The chambers can be compressed to 110 atmospheres (3,600 feet of sea water) and decompressed to simulate altitude exposure to 100,000 feet. A surface exercise laboratory provides measurement of maximum oxygen uptake and ventilatory chemosensitivity. Measurement of blood gases, lactate and hemoglobin can be performed at the surface and inside the chamber. Mass spectrometry provides on-line measurement of mixed expired and end-tidal carbon dioxide and oxygen, with lab based gas chromatography. A temperature-controlled pool is available for head-out immersed or fully submersed exercise. Transthoracic echocardiography can be performed during immersed exercise. Human studies can be performed at altitude or depth with invasive measurement of arterial and pulmonary arterial pressures, transcranial Doppler blood velocity, precordial Doppler monitoring for vascular bubbles, EEG and in vivo near infrared spectroscopy. Also on the premises is an exercise testing facility. Dr. Piantadosi’s laboratory is adjacent, and can process tissue specimens for analysis of histology, molecular pathway markers and activity, and gene expression and activation. An electronics shop and machine shop provide in-house design and construction facilities. The FG Hall Laboratory is within Duke Medical Center, with access to hospital labs, radiology and MR imaging.