On Circadian Lighting: Don't Put Business Before Science

- Jun 04, 2019-

We know that a combination of light levels, spectra and duration of light affects melatonin secretion, but limited data on this aspect has hindered the role of lighting in regulating circadian rhythms and the development of light therapy.

The lighting research center (LRC) at rensselaer polytechnic institute has been studying the extent to which different lighting conditions inhibit melatonin.Recent reports suggest that the amount of nighttime light -- the level of light plus the duration of the light -- may disrupt sleep more than blue light.

"Light amount and spectrum are important, but light amount may have a greater effect on melatonin suppression than the spectrum," said Mariana Figueiro, director of the research center. "people cannot separate these two parameters.Blue light does inhibit melatonin, but the key finding is that it's not just about blue light.If enough energy is emitted in the rest of the spectrum, we'll see a response because the circadian system USES various types of photoreceptors to respond to light and suppress melatonin."

Another study looked at differences between teenagers and adults in their sensitivity to these lighting characteristics that affect circadian rhythms.

Still, lighting suppliers are increasingly marketing products that eliminate the blue light frequency at night.

In a position paper on circadian lighting, the UK's light and lighting association (SLL) said the industry must recognise that our current knowledge of the impact of introducing circadian lighting is limited and do not put commercial sales above science when it comes to so-called human-focused or circadian lighting.

"Commercial sales should not be a priority under any circumstances," especially without evidence or proof, the SLL said.

SLL position paper appears to be more cautious than some standards bodies.

"While developing a metric for circadian lighting is a step in the right direction, it is too early in our current understanding of the factors affecting the human circadian system to provide a high-quality lighting environment with no adverse impact on health and well-being."

"We need to understand other interventions before we can effectively assess the benefits of circadian lighting."It went on.

"Currently, we know that individuals' lighting needs vary depending on factors such as age, sleep type and exposure time.More understanding is needed to provide circadian lighting solutions that meet individual needs."

"In addition, while research is ongoing, some questions should be raised about the effectiveness of products and services that claim to be circadian lighting."

In addition, the American standards organization UL recently published a set of practices and design guidelines for people who design and designate buildings for lighting. It hopes to provide lighting environments that improve visual and circadian rhythms for the typical daytime and nighttime inactive people.The document was opened for public comment last week.The document also provides a simple way to achieve effective light for circadian rhythms and a way to verify the impact on building occupants.