ABSTRACT
Chapter 5 explained that humans have been able to adapt to the stress of life in extreme heat and cold as a result of a combination of cultural and biological adaptations. Two of our major conclusions can be restated here. First, it was noted that the human adaptation to the extreme seasonal cold experienced in the Arctic relies primarily on a superb cultural adaptation in this harsh and difficult environment. With the exception of a few small biological differences, the major way in which people such as the Inuit are able to cope with life in the cold is a combination of technology, cultural knowledge, and experience. Second, it was noted that all humans show the mark of millions of years of tropical heritage; in other words, we all bear the basic biology of tropical dwellers regardless of where we live today. Arctic as well as tropical dwellers share the same basic physiology of efficient sweating and peripheral vasodilation in order to maintain thermoregulatory homeostasis in the heat. By contrast, humans have lived in the world’s high-altitude zones for only a relatively short period of time, measured in thousands of years. Furthermore, the major stress of life at high altitude is hypoxia or low availability of oxygen, which cannot be coped with by cultural adaptations alone, short of wearing oxygen tanks on a daily basis! You will see that the stress of life at high altitude has led to some interesting biological differences between highlands and lowlands dwellers in both the Old World and the New. In this chapter, we will explore the stresses involved in life at high altitude and the mainly biological ways in which people and populations have coped with the low oxygen availability that is the hallmark and major stress of life at high altitude.
