Figure 24.5 shows that the climbers in the 1981 expedition had VO2 max values at sea level that were higher than those of the 1960-1961 expedition. In fact, several of climbers had been competitive marathon runners (139), and, given the need to transport oxygen at these high altitudes to do work, having such a high V02 max would appear to be a prerequisite to success in climbing without oxygen. Subsequent measurements on other mountaineers who had scaled 8500 meters or more without oxygen confirmed this by showing them to possess primarily type 1 muscle fibers and to have an average V02 max of 60 6 ml kg-1 min-1 (91). However, there was one notable exception: One of the subjects in this study was Messner, who had climbed Mount Everest without oxygen; his V02 max was 48.8 ml kg-1 min-1 (91). West et al. (141) provide food for thought in this regard: “It remains for someone to elucidate the evolutionary processes re sponsible for man being just able to reach the highest point on Earth while breathing ambient air.” However, there is more to consider in climbing Mount Everest than a person’s V02 max.