Effects of an Artificial Acclimatization Technique on Infantry Performance in a Hot Climate

Abstract

The performance of an infantry company was first assessed on a three-day exercise in this country. Its twelve sections were then divided into two treatment groups. The experimental group, consisting of the six odd-numbered sections, was subjected to an artificial acclimatization routine consisting of physical exercises in an improvised hot chamber. The control groups consisting of the six even-numbered sections, performed the same exercises in a room of similar proportions at ambient temperatures. After approximately two weeks of these training regimes, the company was immediately flown to Aden where its performance under considerable stress was assessed during a seven-day exercise in the desert. Of eight performance tests only three indicated beneficial effects of artificial acclimatization. The most impressive difference between the two groups was in the number of casualties, most of which occurred during marching tests. Casualty incidence was three times greater in the control group, both for heat casualties and for all casualties regardless of the disorder diagnosed. There are indications that the marching speed of the subjects who carried on may also have been improved by artificial acclimatization. Statistically significant differences in favour of the artificially acclimatized group were also observed on two other performance tests: crossing obstacles and carrying water jerrycans at the run. Questionnaire responses indicated that, by the end of the desert exercise, the individual subject's estimates of his section's effectiveness and his feelings of loyalty to it were more adversely affected in the control group.