Huiberts L M, Smolders K C H J, De Kort Y A W
a Human-Technology Interaction, School of Innovation Sciences, & Intelligent Lighting Institute , Eindhoven University of Technology , Eindhoven , the Netherlands.
Chronobiol Int. 2017;34(7):827-844. doi: 10.1080/07420528.2017.1324471. Epub 2017 May 26.
This study investigated seasonal and time-of-day dependent moderations in the strength and direction of acute diurnal non-image forming (NIF) effects of illuminance level on performance, physiology, and subjective well-being. Even though there are indications for temporal variations in NIF-responsiveness to bright light, scientific insights into potential moderations by season are scarce. We employed a 2 (Light: 165 versus 1700 lx at the eye level, within) × 2 (Season: autumn/winter versus spring, between) × 2 (Time of day: morning versus afternoon, between) mixed-model design. During each of the two 90-min experimental sessions, participants (autumn/winter: N = 34; spring: N = 39) completed four measurement blocks (incl. one baseline block of 120 lx at the eye level) each consisting of a Psychomotor Vigilance Task (PVT) and a Backwards Digit-Span Task (BDST) including easy trials (4-6 digits) and difficult trials (7-8 digits). Heart rate (HR) and skin conductance level (SCL) were measured continuously. At the end of each lighting condition, subjective sleepiness, vitality, and mood were measured. The results revealed a clear indication for significant Light * Season interaction effects on both subjective sleepiness and vitality, which appeared only during the morning sessions. Participants felt significantly more vital and less sleepy in winter, but not in spring during bright light exposure in the morning. In line with these subjective parameters, participants also showed significantly better PVT performance in the morning in autumn/winter, but not in spring upon bright light exposure. Surprisingly, for difficult working memory performance, the opposite was found, namely worse performance during bright light exposure in winter, but better performance when exposed to bright light in spring. The effects of bright versus regular light exposure on physiology were quite subtle and largely nonsignificant. Overall, it can be concluded that acute illuminance-induced NIF effects on subjective alertness and vitality as well as objectively measured vigilance in the morning are significantly moderated by season. Possibly, these greater illuminance-induced benefits during the morning sessions in autumn/winter compared to spring occurred due to increased responsiveness to bright light exposure as a function of a relatively low prior light dose in autumn/winter.
本研究调查了光照水平对表现、生理和主观幸福感的急性昼夜非成像（NIF）效应的强度和方向在季节和一天中的时间上的依赖性调节。尽管有迹象表明NIF对强光的反应存在时间变化，但关于季节潜在调节作用的科学见解却很少。我们采用了2（光照：眼睛水平处165勒克斯与1700勒克斯，组内）×2（季节：秋冬与春夏，组间）×2（一天中的时间：上午与下午，组间）混合模型设计。在两个90分钟的实验环节中，参与者（秋冬组：N = 34；春夏组：N = 39）各自完成四个测量模块（包括一个眼睛水平处120勒克斯的基线模块），每个模块都包含一个心理运动警觉任务（PVT）和一个倒背数字广度任务（BDST），包括简单试验（4 - 6位数字）和困难试验（7 - 8位数字）。连续测量心率（HR）和皮肤电导水平（SCL）。在每种光照条件结束时，测量主观困倦感、活力和情绪。结果清楚地表明，光照*季节交互作用对主观困倦感和活力有显著影响，且仅在上午的实验环节中出现。在上午暴露于强光时，参与者在冬季感觉明显更有活力且困倦感更低，但在春季并非如此。与这些主观参数一致，参与者在秋冬上午暴露于强光时PVT表现也显著更好，但在春季则不然。令人惊讶的是，对于困难的工作记忆表现，结果却相反，即在冬季暴露于强光时表现更差，但在春季暴露于强光时表现更好。强光与常规光照对生理的影响相当细微且大多不显著。总体而言，可以得出结论，季节对急性光照诱导的NIF对主观警觉性和活力以及上午客观测量的警觉性的影响有显著调节作用。可能与春季相比，秋冬上午实验环节中这些更大的光照诱导益处是由于秋冬相对较低的先前光照剂量导致对强光暴露的反应性增加。
