Effect of Thermal Environment on Productivity Evaluated by Task Performances, Fatigue Feelings and Cerebral Blood Oxygenation Changes

Subjective experiments were conducted in a climatic chamber to evaluate the effect of thermal environment on productivity. Chamber was conditioned at operative temperatures of 25°C, 28°C, or 33°C. Several computer tasks were given to the subjects to evaluate task performance. The effects of thermal environment on task performance were contradictory among the task types. According to the evaluation of subjective symptoms of fatigue, the subjects complained of the feeling of mental fatigue more at operative temperature of 33°C than 25°C and 28°C. The cerebral blood oxygenation was monitored by the near infrared spectroscopy. At operative temperature of 33°C, an increment in oxygenated hemoglobin, an increment in total hemoglobin, and a decrement in deoxygenated hemoglobin were found. Evaluation of fatigue feeling and monitoring cerebral blood oxygenation might be applied to the measurement of productivity. INDEX TERMS Productivity, Task performance, Fatigue feeling, Near infrared spectroscopy, Thermal effect INTRODUCTION To evaluate the effect of thermal environment on productivity, subjective experiments were conducted in a climatic chamber (Experiment I). Productivity is defined as the extent to which activities have provided performance in terms of system goals (Parsons, 1993). Thermal environments may affect physiological and psychological process, which may affect activities that may affect performance at tasks that may interact with other factors to affect overall productivity. The effect of thermal environment on productivity was evaluated by task performances, physiological measurements, psychological measurements, and structural analysis of fatigue. In this paper, the results of task performance and feeling of fatigue were reported. The technique of near infrared spectroscopy was used to monitor the changes in cerebral blood and tissue oxygenation. This method allows noninvasive monitoring and it might be possible to apply for the measurement of productivity. To assess the changes in cerebral oxygenated, deoxygenated, and total tissue hemoglobin during brain activation, subjective experiments were conducted by using near infrared spectroscopy (Experiment II). METHODS Evaluation by Task Performance and Fatigue Feeling (Experiment I) To evaluate the effect of thermal environment on productivity, subjective experiments were conducted in a climatic chamber at the Waseda University during November and December 2000. College-age subjects, namely twenty males and twenty females, participated in the experiments. All subjects were volunteers and they were paid at a fixed rate for their participation. To investigate the effect of thermal environment on productivity, it was required ∗ Contact author e-mail: [email protected] Proceedings: Indoor Air 2002