Effect of long term residence in the temperate zone on the physique and sweating reaction of subtropical natives.

Abstract

Anthropometric measurements and observations of physiological responses to heat were made in the summer on 20 young male residents of the Japan mainland who were born in Okinawa but moved to the mainland within less than three years (group S) and 15 young male migrants of Japanese from Okinawa who had lived in the Japan mainland for more than 10 years (group L). Group L showed a thicker skinfold and greater body fat content than group S. Group L showed a greater sweat loss and higher rise in oral temperature than group S. Heat tolerance of group L was inferior to that of group S when assessed by our numerical index for evaluating human heat tolerance. The inferior heat tolerance of group L might reflect a lower efficiency of sweat for cooling the body and an inferior capacity for non-evaporative heat dissipation when compared with group S. The physiological responses of subtropical natives to heat were lost after longterm residence in the temperate zone.