Bank Employees' Fatigue Level in Relation to Office Lighting

Journal of Biological Rhythms

Broad-spectrum light applied during the night has been shown to affect alertness in a dose-dependent manner. The goal of this experiment was to investigate whether a similar relationship could be established for light exposure during daytime. Fifty healthy participants were subjected to a paradigm (0730-1730 h) in which they were intermittently exposed to 1.5 h of dim light (<10 lux) and 1 h of experimental light (24-2000 lux). The same intensity of experimental light was used throughout the day, resulting in groups of 10 subjects per intensity. Alertness was assessed with subjective and multiple objective measures. A significant effect of time of day was found in all parameters of alertness (p < 0.05). Significant dose-response relationships between light intensity and alertness during the day could be determined in a few of the parameters of alertness at some times of the day; however, none survived correction for multiple testing. We conclude that artificial light applied during daytime at intensities up to 2000 lux does not elicit significant improvements in alertness in non-sleep-deprived subjects.

Lighting Research & Technology, 2017

In addition to stimulating the visual system, light incident on the retina stimulates other biological functions, also referred to as non-visual responses. Among the most notable biological functions are human circadian rhythms, which are bodily rhythms that, in constant darkness, oscillate with a period close to, but typically slightly longer than 24 hours. Twenty-four-hour light-dark patterns incident on the retina are the major synchroniser of circadian rhythms to the local time on Earth. Entrainment of circadian rhythms has been implicated in health and well-being. Light can also elicit an acute alerting effect on people, similar to a 'cup of coffee.' This review summarises the literature on how light affects entrainment and alertness and how it can be used to achieve these aims.

Lighting Research & Technology

Light is necessary for vision; it enables us to sense and perceive our surroundings and in many direct and indirect ways, via eye and skin, affects our physiological and psychological health. The use of light in built environments has comfort, behavioural, economic and environmental consequences. Daylight has many particular benefits including excellent visual performance, permitting good eyesight, effective entrainment of the circadian system as well as a number of acute non-image forming effects and the important role of vitamin D production. Some human responses to daylight seem to be well defined whilst others require more research to be adequately understood. This paper presents an overview of current knowledge on how the characteristics of daylight play a role in fulfilling these and other functions often better than electric lighting as conventionally delivered.

Journal of circadian rhythms, 2007

The effects of lighting on the human circadian system are well-established. The recent discovery of &#39;non-visual&#39; retinal receptors has confirmed an anatomical basis for the non-image forming, biological effects of light and has stimulated interest in the use of light to enhance wellbeing in the corporate setting. A prospective controlled intervention study was conducted within a shift-working call centre to investigate the effect of newly developed fluorescent light sources with a high correlated colour temperature (17000 K) upon the wellbeing, functioning and work performance of employees. Five items of the SF-36 questionnaire and a modification of the Columbia Jet Lag scale, were used to evaluate employees on two different floors of the call centre between February and May 2005. Questionnaire completion occurred at baseline and after a three month intervention period, during which time one floor was exposed to new high correlated colour temperature lighting and the other r...

International Journal of Environmental Research and Public Health, 2021

As the primary environmental cue for the body’s master biological clock, light–dark patterns are key for circadian alignment and are ultimately fundamental to multiple dimensions of health including sleep and mental health. Although daylight provides the proper qualities of light for promoting circadian alignment, our modern indoor lifestyles offer fewer opportunities for adequate daylight exposure. This field study explores how increasing circadian-effective light in residences affects circadian phase, sleep, vitality, and mental health. In this crossover study, 20 residents spent one week in their apartments with electrochromic glass windows and another week with functionally standard windows with blinds. Calibrated light sensors revealed higher daytime circadian-effective light levels with the electrochromic glass windows, and participants exhibited consistent melatonin onset, a 22-min earlier sleep onset, and higher sleep regularity. In the blinds condition, participants exhibit...

Clocks & Sleep

Disrupted sleep is common among nursing home patients and is associated with cognitive decline and reduced well-being. Sleep disruptions may in part be a result of insufficient daytime light exposure. This pilot study examined the effects of dynamic “circadian” lighting and individual light exposure on sleep, cognitive performance, and well-being in a sample of 14 senior home residents. The study was conducted as a within-subject study design over five weeks of circadian lighting and five weeks of conventional lighting, in a counterbalanced order. Participants wore wrist accelerometers to track rest–activity and light profiles and completed cognitive batteries (National Institute of Health (NIH) toolbox) and questionnaires (depression, fatigue, sleep quality, lighting appraisal) in each condition. We found no significant differences in outcome variables between the two lighting conditions. Individual differences in overall (indoors and outdoors) light exposure levels varied greatly ...

International Journal of Environmental Research and Public Health

As a critical factor in the built environment, lighting presents considerable influence on occupants. Previous research across static lighting conditions has found that both illuminance and correlated color temperature (CCT) affect occupants’ physiological and psychological functioning. However, little research has been conducted on the non-visual impacts of dynamic lighting with daily variation in illuminance and CCT levels. The purpose of this study is to better understand the impact of dynamic lighting on office occupants’ health, well-being and experience at a living lab. Fifteen participants were recruited to work in three office modules for four months. Four lighting conditions were designed and implemented in this study, including two static lighting conditions and two dynamic lighting conditions with a specific predefined control scheme. A prototype lighting system with enhanced control capabilities was configured and implemented to ensure the desired lighting environment pr...

Indoor and Built Environment

Purpose The International Commission on Illumination (CIE) recommends researchers to investigate a wide variety of behavioural and health outcomes. However, researchers often investigate only a part of occupational health (OH) in relation to light. A literature study (2002–2017) regarding the relationship between office lighting conditions and OH was performed to identify gaps and methodological issues. Method The OH outcomes investigated in this paper were grouped according to the International Classification of Diseases and analysed per category: physical and physiological health, mental health, eye health, sleep parameters and visual comfort. Results Findings from the literature study (20 eligible papers) showed that all OH aspects were mostly but not exclusively measured subjectively. Furthermore, most studies investigated only a fraction of office lighting parameters and OH aspects. Conclusions It seems that Correlated Colour Temperature (CCT) and illuminance mainly correlate w...

Energies

The aim of the study was to define whether changes in psychophysical performance will occur after the exposure to light of a specific color during the early afternoon decrease in work capacity. The evaluation of psychophysical performance was carried out on a group of 50 subjects using the following tools: Grandjean Scale, Attention and Perceptiveness Test (TUS), and GONOGO test. The study was performed for exposure to reference light, white light enriched by blue light (WBL), and white light enriched by red light (WRL). The analysis of psychophysical performance results indicates the positive influence of a specific color of light on different factors of psychophysical performance. Exposure to WRL among participants from the 22–34 subgroup contributed to an increase in the number of correct tests and the speed of work as well as a decrease in the number of mistakes, less boredom, and higher performance. The exposure to WBL among participants from the 55+ subgroup decreased the numb...

Revista Mexicana de Ingeniería Biomédica, 2018

Purpose: An experiment was conducted to investigate the physiological effects of a continuous blue pulsed light emitting diode (BP-LED) added to a task lamp in an actual indoor lighting environment and its influence in alertness having as a final purpose to develop a commercial product that could be applied in situations similar to those depicted in the present work. Design methodology: Previous research studies have stated that the addition of pulsed light evokes physiological changes that may induce alertness. The participants were exposed to four different lighting conditions. Electroencephalograms (EEG), pupil sizes, heart rates (HR), performance tests, and subjective reactions were measured. Findings: Low colour temperature light and the BP-LED revealed an improved alertness according to the data from the EEG recordings. The intervention of the BP-LED in a high colour temperature ambiance was beneficial in maintaining high levels of alertness compared to the conditions where the BP-LED was not used. It was tested that the use of a BP-LED in a task lamp may be beneficial in improving or maintaining alertness levels in an indoor workplace ambiance. Originality and Value: Designing of an adequate workplace task lamp light that improves alertness for in-house, office, or classroom situations in which it is essential.