Subjective and objective assessment of office performance and heat strain at elevated temperatures - The HESO-Study

A study was carried out to investigate whether an elevated room temperature in a summer heat wave affects a subject's mental status, self-assessed performance or impairs a subject's mental performance. In a simulated office environment 20 subjects were exposed to different air temperature conditions: 23-26°C, repeated once, 29-32°C and 33-35°C during outside summer conditions. In the course of 4.25 h selective attention, verbal and numerical thinking did not change significantly neither with temperature nor time. Slight effects on performance were found for text correction. The willingness to exert effort and the feeling of being relaxed decreased significantly both with temperature and time. Drowsiness tended to increase with temperature and rose significantly with time. The feeling of being well-adjusted and self- assessed performance tended to decrease with increasing temperature. The mental and physical work load were perceived to be higher when the temperatures where higher. The results imply the subject's ability to adjust their mental performance in relation to heat strain. A longer exposure time may lead to different results.