Prolonged color temperature exposure: Effects on thermal sensation and underlying neurophysiological pathways

This study explores the time-dependent associations between correlated color temperature (CCT) and human thermal sensation along with potential neurophysiological pathways. Through a 120-min controlled experiment at 25 °C with three CCT conditions (2600K, 4300K, 6000K), we measured subjective thermal sensation votes (TSV) and multi-modal physiological signals (EEG, EDA, HRV, SKT). Results demonstrate that CCT's influence on TSV, with warm light (2600K) elevating and cold light (6000K) reducing thermal sensation, is pronounced within the first 30 min, progressively weakens between 30 and 60 min, and becomes non-significant after 60 min. Exploratory structural equation modeling identified two potential mediating pathways: 'CCT → EEG → TSV' and 'CCT → EEG → EDA/SKT → TSV', suggesting EEG's potential role. EEG analysis showed that the warm light group exhibited relatively higher power in θ, α, and βL bands, particularly in prefrontal regions, compared to the cold light group; these low-frequency group differences diminished after 30-60 min. CCT's group-level differences in skin temperature were subtle and confined to peripheral regions (handback, forearm, forehead, calf), reaching statistical significance during the intermediate phase (20-70 min). These findings outline the temporal dynamics and propose dual neurophysiological pathways linking CCT and thermal sensation, offering preliminary insights for future research on energy-efficient, adaptive photothermal environments.