Perceived well-being and light-reactive hormones: An exploratory study

Abstract

Light can impact psychobiological processes in a healthy or harmful way, challenging designers to better understand the resources they are manipulating. The present exploratory study compared two forms of office lighting which differed in correlated colour temperatures and light level. A holistic approach, comprising visual, emotional and biological dimensions, was used to assess the lighting conditions that could favour productivity and well-being by means of the identification of congruent relationships between objective and subjective measurements in response to light stimuli. The former included analyses of melatonin and cortisol, and the latter were psychological instruments for measuring transitory mood, somnolence, and visual comfort. Controlled experiments were run in a laboratory with a repeated measures design, which yielded fifty-six evaluations. Although no extreme ranges of correlated colour temperatures were used in this study, the spectral blue component present in the correlated colour temperature of approximately 4000 K, and also provided by the light-emitting diodes system at a higher light level, could have contributed to render most of the strong effects on the inter and intra correlations among the psychobiological responses. The mediator role of the psychological profile of the individuals was demonstrated by the significant predictive value of the perceived stress measures.