Department of Biostatistics, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran


Background: Heat stress is a threat to those who work in high temperatures. The purpose in
this study was an examination of the cooling ability of Iranian phase change material (PCM)
cold vest in hot and dry conditions in a climatic chamber. Materials and Methods: This
experimental study was implemented on 12 male students (age 23.7 ± 2.8 years, weight
66.1 ± 11.4 kg, and VO2
 max 2.53 L/min) in 2013. The heat strain score index (HSSI), skin
temperature and oral temperature, and heartbeat in two phases with and without cooling vest
was measured during 30 min in a climatic chamber (temperature 38.8 ± 1.3°C humidity
ratio 32.9 ± 2.3%) and in two activity intensity of 2.4 and 4.8 km/h speed on the treadmill,
and the data differences between groups “with” and “without” vest were tested by t‑test and
repeated measurement. The level of significance was considered as 0.05. Results: The change
in heartbeat at two activities, the oral temperature and heat strain score at 4.8 km/h, did not
differ significantly between groups (with and without vest), as expected (P > 0.05). However,
the change in skin temperature at two activities, oral temperature and heat strain score at
2.4 km/h, was significant between groups, as expected (P < 0.05). The average of skin
temperature at 15th and 30th min during the experiment at two activities of 2.4 and 4.8 km/h
was significant. Conclusion: The findings of the study indicated that using the Iranian PCM
cold vest in hot and dry climate can affect the reduction of skin temperature, oral temperature,
and HSSI in light activities.


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