ADAPTAT1' [GH ALTITUDE 



poorly understood. Accurate time- 

 tables are not available that show 

 rate of adjustment for each organ 

 system including the respiratory, 

 cardiovascular, digestive, endocrine, 

 renal, and neuromuscular systems. 



The time course of the de-acclimat- 

 ization process should also be studied, 

 particularly in those who are exposed 

 intermittently to altitude. 



The working group suggested that 

 a handbook of physiological values 

 be developed which uses standardized 

 terminology. A collection of data 

 on normal and abnormal biological 

 values for different altitudes is ur- 

 gently needed. 



Human Biology at High Altitudes 



The working group considered the 

 problems posed by the biology of 

 human populations living at high al- 

 titudes, which could also, and equally 

 importantly, be relevant to many 

 fundamental problems of human bi- 

 ology in general. 



It seems appropriate to present 

 the recommendations for these two 

 approaches separately, although in 

 practice the methods used and ob- 

 servations made will be closely sim- 

 ilar. 



The Characterization of High- 

 Altitude Populations — Using com- 

 positive methods of approach and 

 standardized procedures, information 

 should be obtained in the following 

 categories: 



1. Fertility and the Components 

 of Fertility: (a) by demographic 

 methods; (b) by methods used 

 in the reproductive physiology 

 of man and of animals, which 

 could be applied to human pop- 

 ulation studies. 



2. Growth, Development, and Ag- 

 ing: With a focus on age 

 changes and variability in char- 

 acteristics thought to be (a) of 



adaptive value at high altitude; 

 and (b) related to the somatic 

 fitness of individuals. Such 

 studies should not be divorced 

 from the psychological and in- 

 tellectual changes that occur 

 during development. 



3. Nutrition: In all cases, the 

 nutritional assessment of the 

 populations studied should be 

 made in as detailed a manner 

 as possible, commensurate with 

 the resources available. Such 

 assessments should include: (a) 

 the nutritional status of indi- 

 viduals; (b) detailed nutritional 

 surveys, where possible; and 

 (c) biochemical studies related 

 to nutrition. 



4. Special Problems Relating to 

 Work Capacity: Both physio- 

 logical and psychological meth- 

 ods should be used. 



5. Epidemiology: In all cases, the 

 pattern of disease distribution 

 in populations should be stud- 

 ied. Where additional demo- 

 graphic information is available, 

 it is highly important that more 

 vigorous epidemiological stud- 

 ies should be made. It is of 

 great importance that demo- 

 graphic methods should be de- 

 veloped which would enable 

 the relationships between age, 

 disease, and morbidity to be 

 ascertained. 



6. Genetics: Further information 

 is required on: (a) the distri- 

 bution of polymorphic systems 

 in high-altitude populations; 

 (b) the heritability of quantita- 

 tive varying traits, particularly 

 those presumed to be adaptive 

 in nature; and (c) congenital 

 defects, especially those pre- 

 sumed to have a genetic com- 

 ponent. 



All these studies must include as 

 precise as possible an analysis of all 

 biological and physical aspects of the 



environment. (See, for e> 

 ure XI-6) Adequate precautions must 

 be taken to insure statistical repre- 

 sentation and control situations, 

 which will often mean the study of 

 lowland populations. And finally, the 

 demographic background of the pop- 

 ulations under study must be ascer- 

 tained in as great a detail as possible. 



Altitude Studies in General Human 

 Biology — The ecological situations 

 of high-altitude populations often af- 

 ford unique opportunities for the 

 study of fundamental human biology. 

 In particular, the following problem 

 areas can be investigated: 



1. Developmental Flexibility: The 

 determination of the magni- 

 tude and biological significance 

 of normal environmentally in- 

 duced responses. 



2. Genetic Structure of Human 

 Populations: Isolated groups, 

 where it may be presumed that 

 factors such as genetic drift 

 may be operative, are partic- 

 ularly important objects of 

 study. Problems involving gene 

 flow and the effects of selective 

 migration may also be encom- 

 passed. 



3. Natural Selection: Of the vari- 

 ety of ways by which the prob- 

 lem of detecting natural selec- 

 tion may be approached, it was 

 thought that particular atten- 

 tion should be devoted to the 

 analysis of the comparative fer- 

 tility and mortality of different 

 phenotypes and, where pos- 

 sible, genotypes. Such investi- 

 gation could be made most 

 appropriately in both stable 

 high-altitude populations and 

 in those which have recently 

 changed their altitude. 



These three topics deal with funda- 

 mental problems of human biology 

 and thus conflict with the objectives 

 of categorizing the biology of high- 

 altitude population, as discussed 



383 



