"The maximum or "vertical limit" of human survivability is around 6000 meters. Extreme heights are called "death zones" and are usually above 8000 meters. Heights higher than 8000 meters are inhospitable for sustained human life. Research indicates that humans cannot live permanently above an elevation of 5500 meters (18,000 feet) without suffering a gradual physiological deterioration that eventually leads to death. Mountaineers who anticipate spending time above this altitude have to fatten themselves before the climb to offset their inevitable weight loss.
As the altitude increases, the barometric pressure decreases. The availability of oxygen decreases as the altitude increases. The increase in oxygen content through the increase in the number of red blood cells is one of the most important mechanisms of adaptation to high altitude. As of May 2003, National Geographic Magazine reports that La Rinconada, Peru, is currently the highest permanent human habitation. La Rinconada, a mining village of over 7,000 people in Southern Peru at an altitude of up to 5100 meters, has been in existence for over 40 years."
As the altitude increases, the barometric pressure decreases. The availability of oxygen decreases as the altitude increases. The increase in oxygen content through the increase in the number of red blood cells is one of the most important mechanisms of adaptation to high altitude. As of May 2003, National Geographic Magazine reports that La Rinconada, Peru, is currently the highest permanent human habitation. La Rinconada, a mining village of over 7,000 people in Southern Peru at an altitude of up to 5100 meters, has been in existence for over 40 years."