Coupled effects of indoor lighting and thermal conditions on cognitive performance, physiological, and subjective responses: A systematic review

Humans spend approximately 90% of their time indoors, where indoor light and thermal environments substantially influence human cognitive performance, subjective perception, physiological responses. To systematically clarify the combined effects of coupled indoor light-thermal environments on occupants, this study followed the PRISMA guidelines and systematically retrieved and screened 28 empirical studies published between 2002 and 2025. A comprehensive analysis framework was constructed from three dimensions: physiological mechanisms, evaluation methods, and combined effects. The results show that temperature is the dominant factor, with an inverted-U model. In the neutral temperature range (22–24°C), both comfort and performance are optimal, and physiological indicators are more stable. Light mainly plays a synergistic regulatory role. Specifically, illuminance levels of 500–1000 lx, when coupled with neutral thermal conditions, can significantly enhance attention and perceptual performance. Correlated color temperature (CCT) primarily regulates emotional arousal and alertness, and may also affect thermal sensation when the ambient temperature is within 22–26°C and the temperature difference does not exceed 2°C.In addition, only about 35.7% of the included studies adopted a three-dimensional evaluation system integrating subjective, physiological, and cognitive-behavioral measures. Moreover, machine learning applications in light–thermal coupled environment research remain at an early stage, accounting for only 7.1% of the analyzed literature. This review identifies the research gaps in existing light-thermal coupled studies and proposes future directions, providing a reference for deepening the understanding of the relationship between light-thermal coupled environment and human responses, as well as for achieving related prediction and evaluation.