Study environment
Two identical study rooms (Fig. Schematic plan of the study location (grey bars indicate the windows of the test rooms).Room temperatures were not monitored during the study, but were measured once in a pilot test before the study began and ranged from 22 to 24 °C. To freshen the air during the study, windows were tilted and doors were opened during a 15-min study break starting at 09:30 AM, during which participants were allowed to consume decaffeinated beverages or leave the study room for a bathroom break. Smoking and socializing were not permitted during the break.