THE EFFECT OF ATROPINE SULPHATE ON MEN EXPOSED TO WARM ENVIRONMENTS

¹ The Chemical Defence Experimental Establishment, Porton, near Salisbury

1. The process of acclimatization to hot dry (110° F., 36 per cent R.H.) and warm moist (90° F., 81 per cent R.H.) environments have been studied using 40 male volunteers, and the effects of I.M. injection of 2 mg. atropine sulphate on the 5th and 10th days of exposure assessed.

2. In both environments acclimatization consisted of a readjustment of cardiovascular balance, an increase in sweat loss (hot and dry only), a decrease in sweat chloride content and an increase in blood volume.

3. Atropine increased circulatory embarrassment by raising the pulse rate and by general vasodilation, and added to the climatic stress by limitation of sweating. In an unacclimatized or partially acclimatized individual in a hot dry environment, circulatory failure and cerebral irritation would be likely to produce casualties before failure of the heat-controlling mechanism could develop.

4. Subjective and individual effects of both heat and atropine are discussed.