LOCAL COOLING IN MAN

Journal/Book: Reprinted from British Medical Bulletin 1961 Vol. 17 No. 1 (Hypothermia and the Effects of Cold) pages 14-18. 1961;

Abstract: R. H. FOX M.B. B.S. Division of Human Physiology Medical Research Council Laboratories Hampstead London 1 Effects of cooling on blood flow 2 Effects of cooling on muscles joints and tendons 3 The effect of cooling on nerves 4 Local acclimatization to cold References The maintenance of a relatively constant deep body-temperature in man is achieved in part at least at the expense of wide temperature changes in the more peripheral tissues. The physiologist wishes to establish the range of such temperature changes in different parts of the body on exposure to particular environmental conditions how such changes in temperature affect the separate and integrated functions of the component tissues and how local changes resulting from cooling one part of the body affect the functioning of other parts and of the organism as a whole. He also seeks to discover whether repeated or prolonged exposure to cold induces adaptive processes which mitigate the detrimental effects of cooling. The majority of the studies in this field have been concentrated on the hands. This is partly because they are man's most vulnerable parts and partly because loss of manual dexterity in cold conditions has important military and economic consequences (Weston 1922; Fisher 1957). There have been many studies in which the effects of exposing the whole man to cool or cold ambient conditions on the performance of particular sensory-motor tasks involving the hands have been assessed (Williams & Kitching 1942; Teichner & Wehrkamp 1954; Russell 1957; Newton Meketon Roote & Stargel 1958; Teichner 1958). Provins & Clarke (1960) have recently reviewed these studies in detail. In general there is a loss of efficiency in cold conditions but it is difficult to determine the extent to which the effects are due to local cooling or to more general factors such as discomfort. Springbett (1951) compared the effects of general versus local cooling using the Minnesota Manual Dexterity Test and concluded that cooling the body-surface did not cause impairment of manual dexterity provided that the hands were kept warm but that if the hands were cooled performance was impaired whether the rest of the body-surface was warmed or cooled. Gaydos (1958) has shown that exposing lightly-clad subjects to an ambient temperature of 45° F. (7.2° C.) so that weighted mean skin temperatures dropped to 78° F. (25.6° C.) had no effect on the performance of knot-tying and block-stringing tests provided that the hands were kept warm. If the hands were also exposed finger skin temperature fell to 50-55° F. (10-12.8° C.) and a significant impairment of performance was observed. ... ___MH

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