Caudwell Xtreme Everest is a research project coordinated by the Centre for Altitude, Space and Extreme (CASE) environment medicine - doctors using extreme physical environments to investigate human physiology.

Caudwell Xtreme Everest placed a research team on the summit of Mount Everest in 2007 and made the highest ever measurement of the level of oxygen in human arterial blood on the Balcony at 8400m.

This was the centrepiece of an extensive programme of research into hypoxia (low oxygen levels), altitude illness and human performance at extreme altitude. The CASE team hope that the lessons learned from studying humans in life at the limits of survival can be brought back to the bedside to help in the care of critically ill children and adults.