Ultrasonic Absorption and Thermal Conductivity of Muscle

Abstract

THE chance of survival in severe cold of an individual already comatose and with arrested peripheral blood flow will depend, other things being equal, upon the rate at which heat escapes by conduction through skeletal tissue from the central body region. Fat acts as thermal insulation, and is indispensable to Channel swimmers¹; but men leading a strenuous life, as in the Armed Services, usually have a thin layer only, and their ultimate tolerance of exposure must depend largely upon the thermal conductivity of their muscle tissue. This is extremely difficult to measure on the living individual; but a large number of tests of excised tissue, human and beef, disclosed a range of variation from more than double the conductivity of fat (which varies little) down to about the same². If this range is indeed present as between normal living individuals, it would be of practical value to find a method of estimating conductivities on the living, as a help in assessing their suitability for enterprises involving exposure as a hazard.