Light exposure in home-based work: Can a simple lighting system increase alertness?

Since the proportion of digital and more flexible work in the western labour market increases, more and more employees are working at least partly from home. This development was even enhanced by the COVID-19-pandemic. In contrast to office workplaces, lighting at home-based workplaces is less studied and regulated. Lighting has been shown to not only ensure vision but also evoke non-image forming effects such as changes in alertness. In this study, light exposure of nine office employees at their home-based workplaces was investigated. Illuminance at home-based workplaces was found to be low, compared to office standards. In addition, melanopic equivalent daylight illuminance (MEDI) did not reach recommendations for healthy daytime light exposure. Furthermore, an additional lighting was installed at participants' desks in order to examine possible effects on alertness. Mean illuminance and MEDI during work were increased by the additional lighting. A decrease in subjective sleepiness could be shown after 6 hours, although differences were not significant. Improvements of response time in a psychomotor vigilance task were already achieved at the beginning of work and after 3 hours. This study shows that lighting conditions at home-based workplaces often do not meet the criteria for health-promoting lighting in terms of non-image forming effects.