Architecture, light, and circadian biology: A scoping review

Light-dark (LD) can support or challenge the circadian organization of physiology and health. As an indoor species, the built environment inevitably influences the patterns and intensities of our LD exposures, thereby affecting health. We reviewed to what extent architectural features have been studied alongside LD and circadian biology. Systematic screening of literature from thirty-one databases identified n = 11 relevant human- and n = 19 relevant field- and simulation- studies; the latter included exploration of LD and architectural details with pertinent reference to circadian biology. Charting and synthesis concerned architecture, LD sources and metrics, circadian biology-related parameters, and health more generally. Human studies that investigate architecture, LD, and circadian biology together are limited by few participants, few architectural features, and few measurements. Most emphasis is on window-related aspects but must be judged as first explorations (i.e., not suitable to compare e.g., glazing vs shading vs position). Novel findings include the potential for time-specific alteration of blue light transmittance through windows. Circadian-light metrics (e.g., the Circadian Stimulus) are in use but analyses of links between architecture and circadian-light metrics together with biology are lacking. In conclusion, first empirical evidence links elements of LD, architecture, and circadian biology. Novel and necessary avenues of research are discussed.