Experimental study on human physiology during repetitive workload simulated under high temperature and high relative humidity

Repetitive workload may cause fatigue and contributed to most cases of workplace related ergonomics injuries in the industries. The purpose of this study is to investigate the physiological responses induced by the repetitive lifting activities based on in the Malaysia construction workers being exposed under high heat and the relative humidity. To achieve the objectives, three male workers participated in this experiments. There were repeated experimental based on the Design of Experiments procedure simulated under environmental temperature (32°C and 25°C) and repetitive lifting task (15 min). The physiological responses measured where the heart rate (HR) and maximum oxygen consumption (VO2max). The experiments were conducted in a thermal climate simulation chamber and the parameters were set-up based on the real working environment. The results showed that the subjects highly experiencing fatigue when they were exposed to high temperature at 32°C. These phenomena were determined through their HR and VO2max, which were increased gradually under prolonged environment exposure. This study found that the significant heat stress increased the workload intensity in repetitive lifting tasks significantly correlated with the physiological responses of the subjects represented through the HR and VO2max. The study concluded the need of management to reconsider the impact of work environmental temperature and relative humidity to their workers especially to those work under tropical climate.