Human cognitive functions and psycho-physiological responses under low thermal conditions in a simulated office environment

Abstract

BACKGROUND: In office environments, thermal comfort is one of the most significant factor affecting employees’ performance. OBJECTIVE: This study aimed to determine the effects of exposure to low air temperatures on human cognitive performance, physiological responses, and thermal perceptions during mental work. METHODS: Twenty-four volunteers with an age range of 18–30 years participated in this study. The subjects were exposed to four different air temperatures (10, 14, 18, and 22°C) in a climate chamber based on a within-subject design. The n-back, CPT, and PVT tests were employed to evaluate some basic aspects of cognitive performance. Body physiological responses and the subjective thermal comfort were also measured. RESULTS: When the thermal condition deviated from relatively neutral temperature, the subjects’ cognitive responses significantly disturbed (P < 0.05), such that the response accuracy was more affected by reduction of air temperature. The blood pressures and heart rate, galvanic skin response, and respiration rate increased as the air temperature decreased (P < 0.05), such that the galvanic skin response as a stress indicator was more affected. In the test configurations, as a result of decrease in air temperature of 1°C, the finger and body skin temperatures reduced to 0.74°C and 0.25°C, respectively. CONCLUSIONS: The findings confirmed that low thermal condition can considerably affect cognitive performance and physiological responses during some office work tasks. The subjects’ thermal comfort votes proposed that air temperature lower than 14 °C can be intolerable for employees during routine mental work. It is suggested that personalized conditioning systems should be used to provide individual thermal comfort in moderate cold air conditions.