Human daily rhythms of renal excretion in a modern arctic Indian settlement during the midwinter darkness

Abstract

Abstract Thirteen years ago, the daily rhythms of renal excretion of Arctic‐dwelling Indians in the Yukon Territory were investigated during the winter darktime (Lobban, 1967). These people were then living close to the land, and it was found that the relative amplitudes (A/M) of their rhythms were appreciably smaller than those of temperate zone control subjects, that the temporal phase was delayed, and that there were significant differences in the total daily excretion of water (Indians> controls) and salt (controls>Indians). No sex or age differences were observed in the group. In the winter 1970/71 the urinary rhythms of another group of Indians (ethnically and, in some cases, directly related to the earlier subjects) were examined at Fort McPherson in the North West Territories, the lifestyle of the people has changed, and this old‐established community has many modern features. The excretory rhythms of 20 Indians (7 male, 13 female; 11 adult, 9 aged; age range 29–91 years, average age 55 years) hav...