طب کار (Dec 2009)
Assessment of the effect of personal protective devices on blood pressure and pulse rate in a noisy environment
Abstract
Abstract Background: Noise, as the most common industrial hazard, besides hearing loss may have adverse effects on other body systems. Many studies have demonstrated the adverse effects of noise on the cardiovascular system. Using personal protective devices is one of the methods for reducing noise exposure. Controlling noise exposure by means of personal protective devices theoretically reduces condiovascular effects of noise, but there isn't any study about this effect. We decided to examine the effects of using personal hearing protective devices in a noisy environment on the systolic & diastolic blood pressure and heart rate. Materials and methods: In an interventional study, 30 workers exposed to 85dB sound or more for 8 hours per workday were assessed. First, after sitting at workplace for 5 minutes, their blood pressure and heart rate was measured three times between 10 and 11 AM, observing the standard conditions. Then, after recommending to wear the earplugs and giving the necessary relevant instructions, all of the workers supervised for wearing the ear-plugs. During 2 weeks of using earplugs, the blood pressures and heart rates were measured again. Results: The mean systolic blood pressure decreased 5.70 mmHg after using the ear-plugs (P=0.004) the mean diastolic blood pressure decreased 2.13 mmHg after using the ear-plugs (P=0.05) and the difference between the heart rate before and after wearing the ear-plugs was not statistically significant (0.635). Conclusion: The abserved difference in blood pressure before and after wearing earplugs, though may not be important clinically, is statistically significant .Thus recommending the workers to use personal protective devices in noisy environment, besides decreasing the effects of noise on hearing, can also reduce the effects of noise on cardiovascular system and can be significant clinically.
