158 TECHNOLOGY / CIRCADIAN RHYTHMS
Left & top left Tests at Ulm University showed significantly improvements instudents’ cognitive performance tests compared to the controls.
Above In mock aircraft cabins, ‘passengers’ benefited from reduced blue spectrum at nightime and increased levels before disembarkation.
Far left The Osram offices filled used different light spectra on different floors to compare the difference.
staff. Besides good scores in the accep- tance of the high CCT-lamp in the office, the major effect showed up in the activ- ity and sleep log data. Illumination with a higher lamp colour temperature led to an enhanced synchronisation of the sleep wake phases to the office hours, published by Céline Vetter in 2011 in the Scandinavian Journal of Work, Environment and Health. On the one hand, this result showed the potential of blue enriched lighting to be ef- fective in normal office conditions, but also the need for aligning the timing of biologi- cally efficient light to natural rhythms. As a consequence, suitable light management systems are required for a proper use of dynamic lighting.
School The Centre for Neuroscience and Learning at the Ulm University, Germany, performed a study with higher class school pupils. Biologically optimised lighting with adapted Siteco Quadrature 2 luminaires in two of the classrooms of the two schools should im- prove cognitive performance and attention abilities, and at the same time reduce so- cial jetlag. Social jetlag occurs because of unsatisfactory sleep/wake patterns due to social schedules, leading to sleep depriva- tion and jetlag-like symptoms in the school
week. By acting on the inner clock, light exposure can positively affect social jetlag. The reference classrooms had a good, but standard lighting. During several weeks of testing, the intervention group performed significantly better in cognitive perfor- mance tests compared to the controls. Sleep logs showed a consistent trend in improved sleep behavior, but did not reach the predefined significance level.
Aircraft Cabin Lighting Non-visual effects of in-flight illumination in an aircraft cabin mockup were tested together with partners from the aircraft industry (Airbus, Diehl Aerospace) and scientific partners (University of Wuppertal, Fraunhofer Institute for Building Physics). Volunteers performed realistically simulated nocturnal long distance flights with either a standard light regimen or a ‘biologically op- timised’ light schedule. Several physiologi- cal and psychological tests and self-reports were conducted to test the hypothesis, that an optimised full-LED cabin lighting can lead to more comfort and regenera- tion in the night and a higher concentration ability after leaving the plane. Therefore, the lighting was adapted in the spectrum and time course. Before the nightly rest phase, the light was smoothly dimmed down
and contained only a minimised fraction of blue. In the morning, this was changed to a brighter light with an enhanced activating blue fraction before disembarkation. The new lighting scheme was highly appreci- ated by the ‘passengers’ and consistent beneficial effects have been demonstrated in reduced evening stress, a better sleep hormone course, and improved after-flight performance.
Summary Application studies have shown that it is possible to stimulate the biological system with traditional and new artificial light- ing solutions when the specific spectral properties of the receptors, their arrange- ment in the retina and a timing aligned to the natural change of lighting conditions are respected. The biological efficiency may be further optimised with progressing scien- tific knowledge in this field. But a growing number of application studies show that the use of existing understanding in this field already now allow us to achieve the desired beneficial effects. To enhance people’s lives – the right light at the right time.
Dr Andreas Wojtysiak is Senior Scientist Light and Health, Light and Health, at OSram AG •
a.wojtysiak@osram.com
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