EFFECTS OF THERMAL ENVIRONMENT IN OFFICE BASED ON THE CIRCADIAN RHYTHM UPON CORE BODY TEMPERATURE AND OTHER PSYCHO-PHYSIOLOGICAL FUNCTIONING, AND INTELLECTUAL PERFORMANCE OF OCCUPANTS

Abstract

This study investigated the effect of diurnal thermal changes on the circadian rhythm of human core body temperature, together with secondary effects on other psycho-physiological functioning and intellectual performance. Four male subjects (23 - 25 years of age) were observed under three experimental temperature cycles in a climate chamber. In Case 1, the temperature remained fixed at 24°C (control); in Case 2, a constant temperature of 24°C during the morning and the afternoon was raised to 27°C at 6 PM and remained constant during the evening, to evaluate the effects of body heating before sleep; in Case 3, the temperature control schedule is similar to Case 2 with the exception of the changing time, not at 6 PM but at noon, to reflect the normal circadian increase in core body temperature (CBT) in the afternoon. The change of the thermal environment caused amplitude increment or phase advance in rectal temperature (RT). Measurements based on electrocardiographs, salivary cortisol levels, psychological measurement tools and intellectual tests illustrated the beneficial effects of the temperature control. The results reveal that control of the thermal environment in spaces based on the circadian rhythm may regulate RT rhythm, leading to improvement in psycho-physiological state and intellectual performance of occupants.