Can lighting help night shift workers?

WORKING NIGHTS is notoriously bad for your health – it’s been linked with chronic disorders such as cardiovascular disease and even cancer. Blame has fallen on the disruption to the sleep-wake cycle, which is set by light. So scientists are now asking: can clever lighting help?

Researchers at the University of Bergen in Norway have started a study which is attempting to work out the type of lighting we should install for shift workers to facilitate their adaptation to night work.

Professor Ståle Pallesen contemplating the new shift work laboratory at the Department of Psychology, University of Bergen.

‘This is important given the reported adverse consequences of shift work for performance, safety, and health,’ Professor Ståle Pallesen of the university told Lux. The project involves a series of three experimental, laboratory-based shift work simulation studies. Sleep is assessed both subjectively and objectively, performance is tested, and waking functions are assessed with objective measures.

The experiment comprises nine office workstations in a room lit by ceiling-mounted LED luminaires, which can be adjusted to provide light of varying intensity and colour temperature.

Thirty four students have been recruited to participate in the first of these night shift simulations. ‘The hypothesis is that night shift workers who can work in environments with high intensity light, or in light with a high colour temperature, will be more alert and perform better during these simulated night shifts,’ says Professor Pallesen. ‘They will also sleep better once the night shift is over, although they might have more problems adapting to a normal sleeping pattern when returning to a day-oriented schedule.’

In order to test this, groups of students will work three consecutive nights in the new laboratory, performing cognitive tests and other tasks designed to measure their alertness and work performance. They will work in light with a colour temperature of 4000K and will alternate between two conditions, one with a light intensity of 1000lx, while the other will provide only 100lx. Similarly, in the second experiment the participants will work three consecutive nights in the same laboratory in light intensity of 200lx. Here the two conditions, between which the participants will alternate, comprise light of 7000K (cool blueish light) and light of 2500K (warm yellow light).

The students will all undergo a range of tests during and after the experiments, including physical measurements such as body temperature and heart rate, and cognitive and mental tests. They will also keep a sleep diary.

The third study will measure the effects of working in monochromatic light. Again, the participants will alternate between different lighting schemes. One condition comprises blue light of 454nm, while the other condition consists of red light of 623nm. These experiments only last for one night in each condition.

The study will explore the effect of different light scenarios including 4000K at 1000lx and 100lx, 2500K at 200lx, 7000K at 200lx, 454nm blue light and 23nm red light

The students will be subject to the same tests and measurements as in the other experiments. The hypothesis is that when the students are subjected to the blue wavelengths they will experience some of the same improvements expected from the groups with high intensity and high colour temperature.

The light in the laboratory is provided by ceiling-mounted  Luxo Modul RC600 luminaires from Glamox with tunable white LED technology and glare-free microprismatic optics. The light scenes are preprogrammed and administered from a wall panel.

‘We are planning to produce several scientific papers from this project,’ says Pallesen. ‘The papers will all be submitted for publication in high impact, international peer review journals. The papers will convey the results on the role of light intensity, the impact of colour temperature, and on the effects of monochromatic light, respectively.’

  • The issue of shift working and human centric lighting will be discussed by a panel of experts at the LuxLive 2017 exhibition and conference in London on Wednesday 15 November. Lighting Design, Mark Ridler of BDP, Mary Rushton-Beales of Lighting Design House and Neil Knowles of Elektra Lighting will discuss the challenge to the lighting design community from the advent of human-centric. They’ll discuss the following questions: Will we stand on the sidelines while a new design community of specialists develops? Or do we embrace it as part of our role? Should we accept a role as quasi-medical practitioners? How do we responsibly turn scientific knowledge into practical application? The debate takes place at 5.10pm on Wednesday 15 November 2017 at the lightspace arena at LuxLive 2017. Entry to LuxLive 2017, which takes place at ExCeL London on Wednesday 15 November and Thursday 16 November 2017, is free if you pre-register HERE.