Blue light key to reducing health risks of night working

20 percent of the workforce in the US and Europe work at night, a situation which could  be putting health at risk. 

People working erratic night-time shift patterns would be better served by LED lighting that features the colour blue, Helen Loomes, business development director at Trilux has told Lux’s Health and Wellbeing Conference.

There is mounting evidence that night-shift workers are at risk of serious health problems because the timing of their work goes against the body’s natural clock, disrupting the internal rhythm of genes.

When placed in comparison with day workers, night workers have been found to have increased levels of cardiovascular disease, obesity and cancer.

The evidence is far from casual and the numbers have so worried the International Agency for Research on Cancer that they have classified shift work as a ‘probable carcinogen’.

Up until recently effort has been put into delaying the body's circadian rhythm in an attempt to tackle the problem, but this can be done only by a small amount and is not enough to mitigate against the risks of shift work.

Lighting however, Loomes told the conference, can be used to rewire and retain a regular circadian pulse while working at night.

Melatonin production throughout the day.

A number of laboratory and field studies have shown that being exposed to light during the night reduces sleepiness, whilst improving alertness.

It has been found, Loomes reported, that a bright light of greater than 1000 lux can act to suppress melatonin, the hormone that anticipates darkness and prepares the body for sleep.

The production of melatonin is suppressed during the day by our natural blue-rich light environment, it is when the blue starts to wane as the day moves towards night that we begin to feel tired.

The spectral distribution at which melatonin is held at bay peaks at 464nm, which is a very strong blue and manufacturers are able to adjust the light output of their modules to take advantage of this knowledge.

Blue saturation has been done before using fluorescent phosphors, but the result was often considered to be far too cold for many working environments. LED technology is providing much finer adjustment in the make-up of white light though, enabling warmer tones to be created, combining the melanopic peak within the spectrum when required.

  • You can find out more about  how light can be used to effect circadian rhythms at this year's LuxLive. The event will be held in London on Wednesday 23 November and Thursday 24 November 2016. You can find a full list of the issues that will be discussed in this year's Lux Arena here.

Comments 2

The Commission Internationale de l'Eclairage declared in 2015 that it is currently impossible to prescribe specific health and wellness benefits from light for general populations. They promised specific recommendations ("prescriptions") as soon as possible, suggesting 2 or more years later. To the best of my knowledge there is yet no CIE-supported prescription about using blue light in this manner. Perhaps the author could comment about this apparent conflict.

This article has to be read in connection with the well-accepted scientific research that shows that exposure to blue LED can have a deleterious effect on eyesight, possibly causing cataracts and macular degeneration several types of cancer (breast, prostate), diabetes, heart disease, and obesity. Yes it suppresses melatonin, but there are better methods ofg coping with night shifts.

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