Heart-rates and the Sub-lingual Temperatures of Heat-acclimatized People

Abstract

PEOPLE resident at sea-level in the equatorial tropics are considered to be ‘naturally’ acclimatized to heat¹. There is evidence that the indigenous peoples of these regions have low forearm blood flows and systolic blood pressures in relation to their surface and deep-body temperatures^2–4. This evidence seems to indicate that the cardiovascular systems of heat-acclimatized people are relatively insensitive to increases of body temperature. If this is true, the relationship between the heart-rates and sub-lingual temperatures of tropical people would be expected to differ from that of people who are not acclimatized to heat. The relationship between the heart-rates and sub-lingual temperatures of young English subjects, at rest in a temperate climate, has been investigated by Tanner⁵. Comparable data are not available for the indigenous peoples of the tropics.