Subjective Evaluation of Physiological Fatigue in Video Data Terminal Operation

Psychological fatigue of the VDT operators is accumulated because of forcible VDT operations. The accumulation of psychological fatigue during the VDT operation is subjectively evaluated by the test in 3 categorized steps. Based on the evaluated results of psychological fatigue, the VDT operation time was decided to be 60 to 120 minutes. The indexes leading to take a rest in order to recover the fatigue of the body positions where the fatigue had been recognized was decided in terms of the change of the rate of the occurrence of the fatigue and in terms of the gradient of that rate when the plot was assumed as a linear function of the number of trials.