Heat stroke: a study of the effects of heat and altitude on the inhabitants of Utrecht, Natal

The underground atmospheric working environment of the Rand mines is hot and humid, and in some cases associated with stagnation of air. Hard manual labour in such conditions may produce pathological reactions, namely, Heat-collapse and Heat-stroke.Heat-collapse is due to cardiac embarrassment brought about by the inability of the heart to cope with the increased physiological demands made upon it by the work and the environment. The symptoms and signs are those of a fatigued heart, namely, headache, dizziness, general feeling of weakness or collapse. The discomfort that these symptoms produce prevents further muscular work and therefore saves the already overworked heart from still further effort. Heat-collapse is therefore in a sense protective.It is only natural that workers who are debilitated as the result of disease are more prone to heat -collapse than normal healthy subjects. Further, the abnormal strain put on the heart, as the result of work in bad underground environment, 7hich normally produces symptoms of heat-collapse, may in diseased subjects be sufficient to bring about a complete breakdown of the heart's action with subsequent death.Heat-stroke is a condition of acute mental excitement with delirium, convulsions, muscular twitchings or tremors and is always associated with a high body temperature. The actual causative agent in the body which precipitates this condition has not yet been established. Hyperpyrexia is merely an accompaniment of the general bodily derangement and is not the causative agent. The invariable absence of diagnosable disease in cases of heat - stroke on admission to hospital, and the subsequent similar findings by Macro- and micro- pathological examination in cases that terminate fatally, is consistent with the fact that co-existing disease does not play a role in precipitating heat-stroke. Unlike heat-collapse, heat-stroke only occurs in unacclimatised subjects. Owing to the acute onset and course of the affliction, treatment directed at anticipating an attack is impossible.Heat-stroke is preventable. Adequate control of the cooling power of the working environment together with a suitable form of underground acclimatisation will eliminate it