High-altitude adaptation in humans is an instance of
evolutionary modification in human populations in
Tibet, the
Andes and
Ethiopia, who have acquired the ability to survive at extremely high
altitudes. The phrase is used to signify irreversible,
long-term physiological responses to high-altitude environments, associated with heritable
behavioural and
genetic changes. While the rest of human population would suffer serious health consequences, these native inhabitants thrive well in the highest parts of the world. These people have undergone extensive physiological and genetic changes, particularly in the regulatory systems of
respiration and
circulation, when compared to the general lowland population. This special
adaptation is now recognised as a clear example of
natural selection in action. In fact, the adaptation account of the Tibetans has become the fastest case of
human evolution in the scientific record, as it is estimated to have occurred in less than 3,000 years.