Effect of Iranian cooling vests with phase change material packs on heat strain indices in hot/ humid conditions in Persian Gulf

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. 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. 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). 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