| Abstract |
The objectives of this study were to investigate the relationship between clothing property factors and physiological effects, and techniques of alleviating physiological strain and enhancement of per...formance of firefighters on physiological and subjective responses while wearing protective clothing (PC). The studies measured rectal temperature (Tre), mean skin temperature (T(－)sk,), heart rate, body weight loss and subjective responses. The first study examined the relationships between clothing properties and physiological effects on physiological/subjective responses for four types of PC, and a light work garment. Eight male firefighters performed a bicycle ergometer exercise at 30%, 45% and 60% of VO2peak for 10 minutes each at 30℃. Clothing surfaces coated with aluminized sliver (PC2) compared to other PCs were almost the same or lower in terms of clothing weight and thermal insulation (clo-value). The latent heat resistance of PC2 was the greatest. Physiological and subjective heat strain in PC2 was greater than for the other PCs. The physiological strain of firefighting protective clothing, shown in the difference between Tre and T(－)sk, depends more upon resistance to latent heat than clothing weight and clo-value, suggesting that latent heat resistance is more closely related than clothing weight or clo-value to the physiological effects. The second study examined the effectiveness of ice-packs (ICE) and phase change material (PCM) cooling devices in reducing physiological load based on subjects’ physiological/subjective responses while exercising on an ergometer and wearing protective clothing at 30℃. Eight non-firefighter subjects participated in four exposures: control (CON), ICE, PCM at 5℃ (PCM[5]) and 20℃ (PCM[20]), rested for 10 minutes, 30 minutes-exercise at 55%VO2peak ,and had a 10 minute-recovery period. An increase in Tre for PCM(5) and PCM(20) which was less than that for CON and ICE was observed. The increases in mean Tsk were depressed using cooling devices, and the cooling effects of PCMs were greater than ICE. The larger surface cooling area, higher melting temperature and softer material of PCMs, which reduce absorption capacity, caused a decrease in Tre and mean Tsk for PCM(5) and PCM(20) which was more than that for CON and ICE. Furthermore, PCM(20) does not require refrigeration. PCM(20) is more effective than other cooling devices in reducing physiological load at 30°C. The final study examined the effects of wearing trousers/shorts under firefighting protective clothing with PCMs on physiological/subjective responses with exercise on a treadmill at 4.8 km・h-1 with a 3% gradient at 30oC for 30 minutes (the average Japanese actual firefighting task time) and the mobility of firefighters. Performance was improved while wearing shorts under protective clothing with PCMs, although no significant difference in reducing thermal stress while wearing shorts instead of trousers was revealed.show more
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Export Mendeley
CHINMEI_CHOU-2009