Comparing the effect of fire fighting protective clothes and usual work clothes during physical activity on heat strain.

Objective: Firefighters must use protective clothing to avoid physical, chemical and environmental damages in their works. Firefighting clothing should cause the minimal physiological, mental and organic limitations on the body, beside their protective features. The aim of this study was to compare the firefighting protective clothing and usual work clothing, in terms of their effects on heat strain during physical activity. Methodology: This is a cross-over study, in which 30 young male were recruited according to inclusion criteria. After choosing the participants, the physical activity was done once by wearing Firefighting protective clothing and again by wearing usual work clothing by random, based on Bruce exercise protocol. Before and after the physical activity, parameters such as Heart rate and Core temperature were measured. The Physiological Strain Index (PSI) was calculated by setting core temperature and heart rate according to Moran’s equation. Results: The results show that the Physiological Strain Index (PSI) was 6.15±1.12 in participants with firefighting protective clothing, while this number was 3.64±0.81 for usual work clothing. This difference is statistically significant (p<0.001). These two sets of clothes are different in their effects on Parameters such as Heart Rate, Core temperature and PSI. The obtained values for usual work clothing are better than firefighting protective clothing. Conclusions: Firefighting protective clothing causes higher level of heat stress and lower tolerance time, because the Physiological Strain Index (PSI) and Core temperature for these clothing was observed higher than the usual work clothing. Heat stress resulted in elevated core temperature which reduce tolerance of firefighters and in severe cases cause risk of heat stress.