Iran Occupational Health

  Background of aims: During physical activity in hot environments , sweating along with evaporation is increased , as the most important physiological response , which can lead to dehydration . The aim of this study was to investigate the variation of urine density in dehydration conditions of workers in hot workplaces.

  Methods: In this cross-sectional study , 40workers in the hot environments were selected as case group and 20 administrative staff s control group . In order to assess dehydration level of the employees, urinary density was measured at the beginning and end of shifts using hand hold model of Refract meter (density gauge device) . In order to evaluate the heat stress in work stations, heat stress index was measured using a digital WBGT meter manufactured by Casella. Ultimately, data obtained from this study were analysed using compare means and Cochran tests by SPSS 16 software.

  Results: In most of workstations, heat stress index was higher than the national recommended limit while this index in the control group was lower than the mentioned limit. Based on the compare means test, the urine density of the case group at the beginning and end of their shift was statistically significantly different(p<0.001).In addition, Based on compare means test ,the urine density of the case group was significantly higher than the control group at the end of work shift (p <0.01).

  Conclusion: The level of urine density with regard to the effects of confounding factors could suitably show the dehydration conditions of workers exposed to heat. Therefore ,the density of urine can be used as an acceptable biomarker for evaluating the occupational exposure to heat in order to determine the risk of inducing the heat strain.