PART XI — HUMAN ADAPTATION TO ENVIRONMENTAL STRESS 



Figure XI-4 — CHANGES IN OXYGEN CONSUMPTION CAPACITY OF 

 LOWLANDERS UPON UPWARD MIGRATION 



The table shows the maximum oxygen consumption capacity of people who nor- 

 mally inhabit lowlands (below 1,000 meters) and then the percentage decrease 

 in their ability to consume oxygen upon moving above 3,000 meters. The decreases 

 are striking except in the last category, those who were children of people 

 acclimated to high altitudes. Decrease in oxygen consumption is reflected as 

 a significant loss in work capacity. 



on men living in the low oxygen 

 pressures found at altitude. 



The formal publication of results 

 on man's adaptational problems at 

 altitude has been substantial since the 

 beginning of 1968, although since 

 that time few new major research 

 efforts have been launched. 



Significance of High-Altitude 

 Research on Man 



The relevance of high-altitude re- 

 search to the 25 million people living 

 above 8,000 feet is obvious because 

 of the multiple health effects. The 

 same is true for those who travel up 

 and down from these altitudes. Less 

 can be said about the problem for 

 the much larger number of people 



living between 5,000 and S,000 feet, 

 since the effects are more subtle and 

 less well known. 



Of perhaps much greater impor- 

 tance, the study of human popula- 

 tions living under the drastically re- 

 duced oxygen pressures found at high 

 terrestrial altitudes can provide data 

 of major importance for both such 

 basic scientific problems as the mech- 

 anisms of human evolution and such 

 applied problems as the causes of 

 cardiovascular disease. For this rea- 

 son, scientists from practically every 

 discipline involved in the study of 

 man have been concerned with high- 

 altitude research. While it may, 

 therefore, be suggested that research 

 on man at altitude is needed because 

 it may help us discover cures for 

 adult cardiovascular disease or im- 



prove the health of a significant seg- 

 ment of the world's population, the 

 major scientific justification is the 

 use of the environmental contrast as 

 a research tool. 



Research Recommendations 



At the 1967 WHO-PAHO-IBP 

 Meeting of Investigators on Popu- 

 lation Biology of Altitude, a detailed 

 set of research recommendations was 

 developed. These needs have not 

 been met. The following research 

 therefore remains of priority interest: 



Physiological Adaptation and Ac- 

 climatization to Altitude Introduc- 

 tion — Several studies have indicated 

 that there are important differences 

 in a variety of structural and func- 



380 



