The Effects of Noise and Whole Body Vibration on Urinary Metanephrine and Normetanephrine

Little attention has been paid to the effects of combined exposure to noise and vibration. Exposure to noise and vibration can effect stress hormones and may lead to high blood pressure and cardiovascular disorders. This study aims to investigate the effects of noise and vibration on urinary Metanephrine and Normetanephrine among men.

In this experimental study, 30 male students were deemed eligible for entry. Background variables such as temperature, light intensity, sound pressure level and vibration acceleration (before and after exposure) were measured throughout each experiment. Participants were randomly exposed to two noise levels and two vibration accelerations for 30 minutes in a combined and independent exposure condition. Urine samples were taken an hour before and an hour after exposure. Metanephrine and Normetanephrine levels were measured using the ELISA method and a specialized Metanephrine/Normetanephrine urinary measurement kit. A repeated measures regression with a Generalized Estimating Equations (GEE) approach was applied for data analysis.

The exposure to noise (at 85 and 91 dB(A)) and independent exposure to whole body vibration at 1.85 m/s2 caused an increase in Normetanephrine and a decrease in Metanephrine concentration although these changes were not statistically meaningful (P>0.05). Combined exposure to noise and vibration caused an increase in Metanephrine and Normetanephrine concentration. These changes were also not statistically significant (P>0.05).

Study subjects’ stress hormone concentrations changed when exposed to noise but did not follow a particular trend. Short term exposure (30 minutes) did not have a distinguish effect on urinary Metanephrine and Normetanephrine concentrations. Therefore, urinary Metanephrine and Normetanephrine concentrations cannot be considered appropriate indicators for noise and whole body vibration exposure.