Cold stress and muscular exercise, with special reference to accidental hypothermia.

An investigation of "exposure " accidents among walkers and climbers revealed the fact that wet clothing and walking to the point of exhaustion were the two outstanding features in fatal accidents (Pugh, 1966a).Subsequent experiments in a climatic chamber showed that the combination of exercise, wind, and wetting reduced the effective thermal insulation of a typical clothing assembly to one-tenth of its nominal value determined at rest in dry, still conditions (Pugh, 1966b).The results also showed that when the subject was exercising at a given work rate in the wet-cold situation his oxygen intake was 50% higher than it was at the same work rate in dry conditions.This finding suggested a possible explanation of the premature fatigue commonly described in exposure accidents, and it seemed desirable to study the phenomenon in more detail. MethodsExperiments were conducted in a climatic chamber at an ambient temperature of 5' C. D.B. (2' C. W.B.).Three young physiologists with experience of hill-walking acted as subjects (Table I).They wore a set of clothing which had been used by one of the hypothermia casualties in the Four Inns Walk (Pugh, 1964).The items were as follows: string vest, woollen shirt and jersey, padded anorak with hood, jeans, heavy woollen socks, gym shoes, and woollen gloves.TABLE I.-Physical Characteristics of Subjects Surface Mean