Hypertension and chronic exposure to noise

The effects of noise on various cardiovascular parameters are conflicting a nd uncertain. In the current study, the authors studied 52 workers who were employed in a bed-frame factory who were chronically exposed to noise and who had poor hearing. An additional group of 65 workers who had jobs in the light-metal sector and another group of 64 office workers served as two co ntrol groups; none of the controls were exposed to noise, and none had hear ing defects. Blood pressure was measured for each person in the supine and standing positions, and an electrocardiogram was also performed. Sound-leve l measurements were taken in the workplaces. Mean systolic and diastolic bl ood pressures and diastolic blood pressure distributions were significantly higher in the noise-exposed group than in both control groups. Among the t hree groups, there were significantly different frequencies of hypertension , drops in blood pressure, and electrocardiogram anomalies. Within the grou p of bedframe workers, those exposed to a personal daily level of exposure (i.e., equivalent continuous noise level for exposure to noise for each ind ividual workers in an 8-hr shift) that exceeded 90 dBA had a higher mean di astolic blood pressure and a higher frequency of diastolic hypertension tha n workers exposed to a personal daily level of exposure of < 90 dBA. The fi ndings suggested that (a) work performed by the bedframe group had some eff ects on the cardiovascular system, (b) noise is a cardiovascular risk facto r, and (c) cardiovascular effects are relative to intensity and type of exp osure. Vascular damage often accompanies auditory damage, but-depending on individual susceptibility-the cardiovascular system can respond in various ways.