Iranian Journal of Ergonomics

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Abstract Background: Heat exposure is one of the harmful agents at work environments. Workers in high temperature environments are susceptible to heat strain. The purpose of this study was to evaluate the performance of Iranian cooling vests containing phase change material in hot and humid conditions in the Persian Gulf. Materials and Methods: This interventional study carried out on 6 subjects of oil tanker ship's engine room staff in summer in 2013. The Heat Strain Score Index (HSSI), oral temperature and blood pressure measured with and without the cooling vest wearing for two hours, and data were analyzed by paired t test. Results: The mean oral temperature were 36.98± 0.22 °C (without cooling vest) and were 36.68± 0.68°C (cooling vest) at 30th minutes in heat exposure. The mean oral temperature were 37.06± 0.25 °C (without cooling vest) and were 36.78± 0.16°C (cooling vest) at 60th minutes in heat exposure. (p <0.042) and also HSSI was 12.72 ±3.03 (without cooling vest) and 8.65 ±2.9 (with cooling vest) (p <0.039) but the mean systolic and diastolic blood pressure were not significant statistically with and without the use of cooling vests (p>0.05). Conclusion: Our findings showed that cooling vests with phase change material packs reducing heat strain (oral temperature and perceptual heat) in hot and humid climates in Persian Gulf

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Introduction: This study aimed to investigate the effects of cooling vests on heat strain and reaction time while wearing protective clothing against chemical, biological, and radioactive contamination.

Materials and Methods: Twelve male students with the mean age of 25 ± 2 years and mean body mass index (BMI) of 23.0 ± 1.5 kg/m2 were recruited in this experiment. Each student was asked to run on a treadmill at a speed of 2.4 km/h for 20 minutes. The experiments were performed at 35 °C and 30% relative humidity. Physiological strain index score, oral temperature, heart rate, reaction time, and number of errors were measured at the end of the two phases. The findings were analyzed by SPSS.

Results: According to Wilcoxon test, exercising with and without the cooling vest resulted in significantly different physiological strain index scores (P = 0.02), oral temperature (P = 0.02), reaction time (P = 0.02), heart rate (P = 0.02), and errors (P = 0.03). The mean physiological strain index score was 4.038 ± 0.882 without the cooling vest and 1.42 ± 0.435 with the cooling vest. The mean reaction times with and without the cooling vest were 0.539 ± 0.977 and 0.769 ± 0.0972, respectively.

Conclusion: The results of this study showed that using a cooling vest reduced the physiological strain, reaction time, and error rates in workers.