Diurnal biological effects of correlated colour temperature and its exposure timing on alertness, cognition, and mood in an enclosed environment

YanJie Li; WeiNing Fang; HanZhao Qiu; Hongqiang Yu; WenLi Dong; Zhe Sun

doi:10.1016/j.apergo.2024.104304

Diurnal biological effects of correlated colour temperature and its exposure timing on alertness, cognition, and mood in an enclosed environment

Appl Ergon. 2024 May 7:119:104304. doi: 10.1016/j.apergo.2024.104304. Online ahead of print.

Authors

YanJie Li¹, WeiNing Fang², HanZhao Qiu³, Hongqiang Yu⁴, WenLi Dong⁵, Zhe Sun⁶

Affiliations

¹ School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, No. 3 Shang Yuan Cun, Haidian District, 100044 Beijing, China. Electronic address: 21116007@bjtu.edu.cn.
² School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, No. 3 Shang Yuan Cun, Haidian District, 100044 Beijing, China; State Key Laboratory of Advanced Rail Autonomous Operation, Beijing Jiaotong University, No. 3 Shang Yuan Cun, Haidian District, 100044 Beijing, China. Electronic address: wnfang@bjtu.edu.cn.
³ School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, No. 3 Shang Yuan Cun, Haidian District, 100044 Beijing, China. Electronic address: hzhqiu@bjtu.edu.cn.
⁴ National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Haidian District, 100094 Beijing, China. Electronic address: yuhq_acc@foxmail.com.
⁵ School of Automation and Intelligence, Beijing Jiaotong University, No. 3 Shang Yuan Cun, Haidian District, 100044 Beijing, China. Electronic address: 20111066@bjtu.edu.cn.
⁶ School of Automation and Intelligence, Beijing Jiaotong University, No. 3 Shang Yuan Cun, Haidian District, 100044 Beijing, China. Electronic address: 23111075@bjtu.edu.cn.

PMID: 38718532
DOI: 10.1016/j.apergo.2024.104304

Abstract

Artificial lighting, which profits from the non-visual effects of light, is a potentially promising solution to support residents' psychophysiological health and performance at specific times of the day in enclosed environments. However, few studies have investigated the non-visual effects of daytime correlated colour temperature (CCT) and its exposure timing on human alertness, cognition, and mood. However, the neural mechanisms underlying these effects are largely unknown. The current study evaluated the effects of daytime CCT and its exposure timing on markers of subjective experience, cognitive performance, and cerebral activity in a simulated enclosed environment. Forty-two participants participated a single-blind laboratory study with a 4 within (CCT: 4000 K vs. 6500 K vs. 8500 K vs. 12,000 K) × 2 between (exposure timing: morning vs. afternoon) mixed design. The results showed time of the day dependent benefits of the daytime CCT on subjective experience, vigilant attention, response inhibition, working memory, emotional perception, and risk decisions. The results of the electroencephalogram (EEG) revealed that lower-frequency EEG bands, including theta, alpha, and alpha-theta, were quite sensitive to daytime CCT intervention, which provides a valuable reference for trying to establish the underlying mechanisms that support the performance-enhancement effects of exposure to CCT in the daytime. However, the results revealed no consistent intervention pattern across these measurements. Therefore, future studies should consider personalised optimisation of daytime CCT for different cognitive demands.

Keywords: Correlated colour temperature; Daytime; Enclosed environment; Neurobehavioural responses; Non-visual.