Effect of ambient temperature and humidity on muscle fatigue of pilots

Abstract: From scientific research and accident investigations, we are aware of the effects of fatigue on our performance. Pilots’ fatigue has been considered a contributing factor in various aviation accidents; many researchers found that pilots’ muscle fatigue makes pilots slow to respond and slow down their movements, which will bring potential safety hazards to flight. The aim of this study is to investigate the effect of different cockpit ambient temperatures (Ta) and relative humidity (RH) on pilots’ muscle fatigue. Thirteen subjects participated in the simulated flight experiments at 21℃/30%, 30℃/45%, and 38℃/60%RH. Continuous measurement of the skin temperature (Tsk) and skin humidity (Hsk) throughout the experiment, the surface electromyography (EMG) signals of biceps brachii (BB), flexor carpi radialis (FCR), rectus femoris (RF), and tibialis anterior (TA) were recorded, the mean power frequency (MPF) of EMG data were analyzed. This study found that the mean power frequency of rectus femoris (RF) and tibialis anterior (TA) at 38°C/60% and 30°C/45% were lower than 21°C/30% (p<0.001), and the MPF of RF at the high ambient temperatures and relative humidity condition was lower than that of TA, biceps brachii (BB) and flexor carpi radialis (FCR) (p<0.001). Through the analysis of binary linear regression, it was found that there was a relationship between ambient temperatures and relative humidity and the change of root mean square (p<0.003). This study showed that the ambient temperatures and relative humidity would impact flight fatigue, and high temperature and humidity are more likely to cause fatigue. Also, in this study, the rectus femoris is more likely to cause fatigue during flight. This study can provide a reference for biological therapies targeting flight fatigue and fatigue prevention of fighter pilots.

Keywords: Flight fatigue, surface electromyography, high temperature, high humidity, cockpit

DOI: 10.54941/ahfe1003963

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