BACKGROUND: One of the most important impacts of industrial noise is physiological and psychological effects. The increases in workers’ blood pressure and heart rate were detected during and after exposure to high levels of noise. The objectives of this research were to determine whether the noise exposures have any effects on blood pressure and heart rate of workers in the automotive parts industry. METHODS: This case study was done in ۲۰۱۱ at different units of an automotive parts manufacturing in Tehran. Sound pressure level was measured at different units of the factory with a calibrated instrument. Demographic features of workers were gathered with an appropriate questionnaire. Heart rate and blood pressure were measured twice in a day in the start time of work day (before exposure to noise) and middle shift hours (during exposure to noise) in the occupational physician office. For analyzing data, chi-square, independent sample t-test, paired t-test, and analysis of covariance (ANCOVA) were used. P < ۰.۰۵۰ was considered statistically significant. RESULTS: The average age of workers in the case and control groups was ۳۵.۷۱ ± ۸.۱۰ and ۳۳.۴۰ ± ۱۰.۴۱ years, respectively. There was no difference between the average age of case and control groups (P = ۰.۴۳۶). The results of ANCOVA revealed the significant differences between the mean changes of heart rate F (۱, ۳۷) = ۲۶.۶۸, P < ۰.۰۰۱, systolic blood pressure F (۱, ۳۷) = ۲۱.۷۰, P < ۰.۰۰۱, and diastolic blood pressure F (۱, ۳۷) = ۲۶.۲۰, P < ۰.۰۰۱ of workers in the case and control groups. CONCLUSION:
Exposure to industrial noise may increase the heart rate of workers. Although rises in heart rate, systolic, and diastolic blood pressure of workers in the case group were observed after exposure to noise, the values of heart rate, systolic, and diastolic blood pressure were in the normal range. Further experimental investigations are needed to determine the relationships between these variables.