Office workers’ daily exposure to light and its influence on sleep quality and mood

Abstract

"This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively." Hubalek, Sylvia; Brink, Mark; Schierz, Christoph: Office workers' daily exposure to light and its influence on sleep quality and mood URN:urn:nbn:de:gbv:ilm1-2014210273 To study the amount of light entering the eye and its effects on office workers, measurements were taken from 23 office workers over a period of seven consecutive days. Two parameters of visible light were recorded: (i) illuminance and (ii) irradiance of the blue spectral component. Every evening before going to bed, a questionnaire had to be filled out, containing scales relating to the mood dimensions of pleasure and arousal, questions about the previous night's sleep and a rough time table with information about the person's whereabouts during the day. The exposure to light on workdays is regular but it varies strongly on days off. No evidence could be provided for the influence of age, sex or seasonal affective disorder (SAD) scores on the daily exposure to light of office workers. The amount of light entering the eye during the day appears to have a positive impact on sleep quality the following night. Pleasure and arousal were not significantly associated with daily light exposure.

The Physiological and Psychological Effects of Windows, Daylight, and View at Home: Review and Research Agenda

“…More direct evidence for this relation comes from aan het Rot et al (2008), who observed positive relations between bright light exposure and both arousal and pleasant mood, using an event-contingent recording protocol that allowed them to connect light exposures and the mood immediately following. Hubalek et al (2010), however, did not find any correlation between daily light…”

“…Hubalek, Brink, and Schierz (2010) found that office workers' light exposure patterns differed markedly between workdays and days at home; some of the days at home showed very low light exposures. The daily patterns for this sample were quite different from previously reported data for security guards in the same country (Koller, Kundi, Stidl, Zidek, & Haider, 1993).…”

“…As seen in Table 1, even in southern California the wintertime light exposures are quite low; at higher latitudes, wintertime exposures are less than half an hour per day -although it is not clear from the currently available data whether the short exposure time relates to the shorter day length at higher latitudes, or to the colder outdoor temperatures, or both. (Cole et al, 1995) wrist 24 143 23 San Diego, CA (33°N) (Espiritu et al, 1994) wrist 106 130 80 Zurich, Switzerland (47°N) (Hubalek, Brink, & Schierz, 2010) spectacles 23 105…”

Effects of environmental colour on mood

“…al. recently reported a study on light levels to which office workers were exposed but was not able to conclude anything on the relationship between exposure to different light colours, and mood or cognitive performance [12]. Given the known strength of visual imagery as a cue to accessing memories [8], in this work we investigate whether colour alone can act as a sufficient prompt to help understand the lighting environments that a person is exposed to, thus being a valuable tool to the ergonomic research community.…”

“…orange and yellow are known as "warm" and blue, green and purple are known as "cold" and that warm colours are associated with happiness, pleasure, energy and stimulation while the cold colours are associated with calmness, healing, sadness. These chromatic effects from exposure to variations in colour temperature have theraputic properties and chromotherapy, the use of colour in therapy, has been practiced for millenia [12].…”