Heart-rate and blood-pressure response in medium-artillery gun crews

A pilot study of the effect of firing the L118/119 British light gun on the heart rate and blood pressure of crewmen who were wearing EAR ear-plugs was carried out. The firing took place on two successive days, with a higher (louder) charge being used on the second day. Each day 40 rounds were fired from each of two guns which were placed 7 m apart. The results suggest that an increase in heart rate of 10%-30% occurs which is attributable to the noise and which does not habituate to successive firings, and that an acute rise in blood pressure may have been associated with the firing of the higher-powered charge. It is considered that these preliminary observations warrant further, controlled experimentation with a larger number of subjects and improved methods of monitoring blood pressure levels.