[The influence of noise increased arterial blood pressure in workers during the work day]

The arterial blood pressure was measured three times: before beginning of work on morning shift, after 3-4 hours of work, and after its completion in 2599 workers exposed to continuous or intermittent noise of over 90 dB intensity and in 2454 controls. The rise of the systolic and diastolic pressure during the working day depended on the initial pressure level, age and duration of employment as well as the exposure to noise. Among these variables the effect of noise was most significant, and the importance of this factor increased with increasing duration of employment. In the group exposed to noise and in the controls the greatest rises of the systolic and diastolic pressure during working day were noted in workers with borderline hypertension, and were low in those with normal pressure. On the other hand, workers with systolic hypertension were most prone to diastolic pressure rise. A reverse observation was made in workers with diastolic hypertension. In all groups exposure to noise increased the pressor reaction.