High altitude living: Genetic and environmental adaptation

High altitude (HA) living produces physiological changes for adaptation to chronic hypobaric-hypoxemic conditions. Although much is known about these physiologic adaptations, no clear separation has been made regarding what i s "native" or "genetic" adaptation and what is "acquired." In this review, we describe the genetic vs. acquired adaptation and only include studies pe rformed in a population native to HA and not in an acclimatized population or trekkers. The changes encountered in animals and humans living at HA in terms of hematology, muscular, respiratory, cerebral, cardiovascular, hormo nal, fluid and electrolytes and reproduction, strongly suggest that genetic s play a very important role in HA adaptation. Unfortunately, the character istic physiology of HA natives has not been systematically defined to estab lished specific measurable parameters of adaptation in comparison to the ac quired ambient adaptation of the non-native population. Once the parameters am established, we can compare non-native populations exposed to HA that m ust emulate the HA physiology for a definite adaptation to be present. With measurable parameters, especially in the management of fluids and electrol ytes, we can define how long it will take for a sea level native to adapt t o an HA altitude. Until these studies are performed, speculation will conti nue and no rational medical intervention can be offered to HA newcomers who may experience HA difficulties.