Respiratory function in Peruvian Quechua Indians

Measurements of respiratory function (forced expiratory volume, forced vital capacity, and their ratio) were obtained from male Quechua Indians living at high altitude and at sea level in Peru. The samples included migrants from one altitude level to another, and also juveniles from 12 to 19 years old. Information on age, stature and weight was also collected. Differences in respiratory function according to altitude were found, with high altitude groups showing higher lung volumes and ratios, and lower rates of decline in these with age. It is concluded from the study of the migrants that these differences in respiratory characteristics are of immediate environmental origin; and that highland migrants to sea level come to resemble the coastal groups in their respiratory characteristics, although they retain their low weight and short stature. Examination of the juveniles indicates that the differences due to altitude are present from at least 12 years onwards. It is shown that both high-altitude and sea-level Quechua Indians have high expiratory volumes and vital capacities, compared with other world populations, although when adjustment is made for differences in body size they are similar to other groups living at high altitude, such as Bhutanese and Ethiopians. The relatively high respiratory value, found even among sea-level Quechua, suggests a racial difference in respiratory function, and implies that the Quechua as a whole can be regarded as highland peoples who have been exposed for many generations to such natural selection as high-altitude living imposes.