Lok Renske, Joyce Daniel S, Zeitzer Jamie M
Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, United States of America.
Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, United States of America; Department of Psychology, University of Nevada, Reno, Reno, NV 89557, United States of America.
J Photochem Photobiol B. 2022 May;230:112439. doi: 10.1016/j.jphotobiol.2022.112439. Epub 2022 Mar 28.
Light at night can improve alertness and cognition. Exposure to daytime light, however, has yielded less conclusive results. In addition to direct effects, daytime light may also mitigate the impact of nocturnal light exposure on alertness. To examine the impact of daytime lighting on daytime cognitive performance, and evening alertness, we studied nine healthy individuals using a within subject crossover design. On four visits, participants were exposed to one of four lighting conditions for 10 h (dim fluorescent, room fluorescent, broad-spectrum LED, standard white LED; the latter three conditions were matched for 100 lx) followed by an exposure to bright evening light. Cognitive performance, subjective and objective measures of alertness were regularly obtained. While daytime alertness was not impacted by light exposure, the broad-spectrum LED light improved several aspects of daytime cognition. The impact of evening light on alertness was not mitigated by the pre-exposure to different daytime lighting conditions. Results suggest that daytime exposure to white light with high melanopic efficacy has the potential to improve daytime cognitive function and that such improvements are likely to be direct rather than a consequence of light-induced changes in alertness.
夜间光照可提高警觉性和认知能力。然而，白天光照的效果却不那么确凿。除了直接影响外，白天光照还可能减轻夜间光照暴露对警觉性的影响。为了研究白天光照对白天认知表现和夜间警觉性的影响，我们采用受试者内交叉设计对9名健康个体进行了研究。在四次访视中，参与者在10小时内暴露于四种光照条件之一（昏暗荧光灯、室内荧光灯、广谱LED灯、标准白色LED灯；后三种条件的光照强度均为100勒克斯），随后暴露于明亮的夜间光照下。定期获取认知表现、警觉性的主观和客观测量结果。虽然白天的警觉性不受光照暴露的影响，但广谱LED灯改善了白天认知的几个方面。不同白天光照条件的预先暴露并没有减轻夜间光照对警觉性的影响。结果表明，白天暴露于具有高黑素效能的白光有可能改善白天的认知功能，而且这种改善可能是直接的，而非光照引起的警觉性变化的结果。
