Morning boost on individuals' psychophysiological wellbeing indicators with supportive, dynamic lighting in windowless open-plan workplace in Malaysia

Acute effects of light during daytime on central aspects of attention and affect: A systematic review

Light regulates both image- and various non-image forming responses in humans, including acute effects on attention and affect. To advance the understanding of light's immediate effects, this systematic review describes the acute effects of monochromatic/narrow bandwidth and polychromatic white light during daytime on distinct aspects of attention (alertness, sustained attention, working memory, attentional control and flexibility), and measures of affect (self-report measures, performance-based tests, psychophysiological measures) in healthy, adult human subjects. Original, peer-reviewed (quasi-) experimental studies published between 2000 and May 2024 were included according to predefined inclusion and exclusion criteria. Study quality was assessed, and results were synthesized across aspects of attention and affect and grouped according to light interventions; monochromatic/narrowband-width or polychromatic white light (regular white, bright white, and white with high correlated color temperature (CCT)). Results from included studies (n = 62) showed that alertness and working memory were most affected by light. Electroencephalographic markers of alertness improved the most with exposure to narrow bandwidth long-wavelength light, regular white, and white light with high CCT. Self-reported alertness and measures of working memory improved the most with bright white light. Results from studies testing the acute effects on sustained attention and attentional control and flexibility were inconclusive. Performance-based and psychophysiological measures of affect were only influenced by narrow bandwidth long-wavelength light. Polychromatic white light exerted mixed effects on self-reported affect. Studies were strongly heterogeneous in terms of light stimuli characteristics and reporting of light stimuli and control of variables influencing light's acute effects.

The Impact of Different Color Temperatures and Sources of Light on Mood and Vision: Acuity and Color Recognition

Background: Light is a physical factor that can influence the mood and vision of people during work and study. According to the importance of these physical factors, the present study aimed to investigate the effect of the source and color temperature on the mood and vision (acuity and color recognition) of students of TUMS and USWR medical universities. Methods: The present study is an applied study, and the research method is quasi-experimental. Twenty subjects were determined by first-type error (0.05) and test power (0.08). The mood was measured using the profile of mood states (POMS), visual acuity in different lighting conditions based on Snellen and FrACT methods, and color recognition by Ishihara’s test. Data were analyzed by SPSS 22, one-way ANOVA, and Greenhouse-Geisser. Results: The results of investigating six subscales of the POMS scale in sunlight, LED, and fluorescent with color temperatures of 4000 K and 3000 K indicated improvement in mood states (P < 0.001). Color recognition under different lighting conditions showed no significant difference (P < 0.05). However, visual acuity with the FrACT method under sunlight showed a significant difference in other lighting conditions (P < 0.001). Conclusions: Light sources can influence mood and vision states (acuity and color recognition) under different lighting conditions. Therefore, using sunlight in educational environments can improve the mood and state of students.

Abrupt light transitions in illuminance and correlated colour temperature result in different temporal dynamics and interindividual variability for sensation, comfort and alertness

Detailed insights in both visual effects of light and effects beyond vision due to manipulations in illuminance and correlated color temperature (CCT) are needed to optimize study protocols as well as to design light scenarios for practical applications. This study investigated temporal dynamics and interindividual variability in subjective evaluations of sensation, comfort and mood as well as subjective and objective measures of alertness, arousal and thermoregulation following abrupt transitions in illuminance and CCT in a mild cold environment. The results revealed that effects could be uniquely attributed to changes in illuminance or CCT. No interaction effects of illuminance and CCT were found for any of these markers. Responses to the abrupt transitions in illuminance and CCT always occurred immediately and exclusively amongst the subjective measures. Most of these responses diminished over time within the 45-minute light manipulation. In this period, no responses were found for objective measures of vigilance, arousal or thermoregulation. Significant interindividual variability occurred only in the visual comfort evaluation in response to changes in the intensity of the light. The results indicate that the design of dynamic light scenarios aimed to enhance human alertness and vitality requires tailoring to the individual to create visually comfortable environments.

Effects of light transitions on measures of alertness, arousal and comfort

Knowledge on the onset, persistence, and symmetry of effects of lighting transitions on humans is relevant when designing dynamic lighting scenarios and, additionally, can shed light on the dominance of underlying mechanisms. We examined temporal trajectories in measures of alertness, arousal and comfort after abrupt lighting transitions that were created using two strongly contrasting light conditions (warm, dim lighting vs. cool, bright lighting). In this controlled within-subjects experiment, thirtyeight healthy subjects participated in four separate sessions of 90 min. Subjective experiences (alertness, comfort and mood) and objective measures of vigilance (PVT performance), arousal (HR, HRV, SCL), and thermoregulation (skin temperature and DPG) were studied. The comparison of the temporal trajectories following the transition in light for the different variables indicates a complex interplay of underlying physiological and psychological processes driving these effects.

Correction: Morning boost on individuals' psychophysiological wellbeing indicators with supportive, dynamic lighting in windowless open-plan workplace in Malaysia

[This corrects the article DOI: 10.1371/journal.pone.0207488.].