“While the first generation of LED lighting radically improved energy efficiency, these LEDs were not designed to deliver the circadian light spectrum our brains and bodies require to entrain our circadian rhythms and promote health and well-being”, explained Dr. Martin Moore-Ede, CEO of CIRCADIAN ZircLight, and former professor at Harvard Medical School. “This has had unintended consequences such as sleep disorders and fatigue and other health-related issues as acknowledged by the World Health Organization, American Medical Association and the NIH National Toxicology Program to be linked to the circadian disruption caused by the effects of continuous blue-rich lighting.”
Evidence-Based Circadian Lighting
To develop LEDs that optimize human health and performance, CIRCADIAN ZircLight conducted multiple medical research studies to precisely define the circadian spectral characteristics of light under normal workplace conditions. At the University of Toronto Professor Robert Casper’s team studied nurses and other volunteer subjects wearing eyewear spectral filters as they worked 12-hour night shifts. And Dr. Moore-Ede and his team at CIRCADIAN studied subjects working 12-hour day and night shifts under polychromatic white light sources with diverse spectral distributions and measured various physiological responses, including melatonin and insulin levels. This research discovered the circadian disruptive effects of light at night were largely confined to a narrow band of 440-490nm blue light with a peak at 475nm as defined by the Circadian Potency curve.
“People want healthy circadian lighting - demand is growing rapidly” said Dr. Moore-Ede. “But how do you determine if a light is truly a circadian solution? Our research revealed it’s not by how warm or cold is the color temperature of the light, but rather by how much blue light is emitted between 440-490nm. During the day, you want blue-rich light sources. But at night, you want as little blue light exposure as possible – ideally under 2%. Unfortunately, many circadian lights that are marketed for night use are well over this 2% threshold.”
Spectrally Engineering the Optimal LED: 85-Fold Difference in Day and Night Blue Levels
Driven by the need to remove the harmful 440-490nm blue wavelengths at night and restore them during the day, a bio-engineering team led by Dr. Moore-Ede spectrally engineered an innovative healthy white LED solution. CIRCADIAN® ZircLight’s revolutionary Zirc™ technology – with Zirc™ Day LEDs and NightSafe™ LEDs - provides an unparalleled 85-fold day-night contrast between blue emission at the peak Circadian Potency 475nm wavelength.
Compared to conventional LEDs with 15-20% blue emissions, the Zirc™ NightSafe™ LEDs deliver only 1% of 440-490nm blue content, easily meeting the UL verification mark for lighting between sunset and sunrise of “Less than 2% Blue Light at Night.” And during the day the Zirc™ Day LEDs deliver the rich blue content that is critical to entraining our circadian rhythms and promoting health and well-being.
Not only does Zirc™ patented technology provide a robust circadian entraining light solution, but with approximately 130 lumens/ watt delivered 24/7 the Zirc™ LED technology delivers energy-efficiency without sacrificing health benefits.
“As a market leader in lighting and building management solutions, we are very excited to be working with CIRCADIAN to commercialize circadian lighting technology to support our customers’ growing desire to use lighting that is designed to promote well-being,” said Rick Earlywine, Acuity Brands Lighting Senior Vice President, Architectural Lighting Solutions.
Why is 475nm Blue Light the Peak Circadian Signal?
Billions of years ago when life first began, the only part of the sunlight spectrum that penetrated the ocean depths was 475nm blue. All other spectral colors in sunlight are absorbed by sea water, so days were blue and nights black. Circadian clocks evolved using 475nm blue as the signal for day and night. New research now shows that our eyes, like the primitive ocean life, use blue light with a peak wavelength of 475nm as the signal for circadian entrainment. While short exposures in dark adapted laboratory volunteers may show some transient effects of violet and green, the key circadian signal is 475nm blue. Circadian ZircLight™ LED’s are spectrally engineered to adhere to this fundamental law of nature.
In the natural world there is a greater than five orders of magnitude day-night contrast in 475nm blue between a 10,000 lux cloudy day and 0.1 lux of full moonlight which provides a strong circadian entrainment signal. But unlike our ancestors we spend over 93% of our time indoors with conventional fluorescent and LED lighting which can emit too little blue rich light during the day and too much blue-rich light at night.
“Our goal was to create lights that combine the longevity and energy efficiency of LEDs with the ideal spectrum of light by time of day, season and geographical location to entrain circadian rhythms and optimize human health and performance”, explained Dr. Moore-Ede. “Our NightSafe™ LEDs utilize a violet pump to provide the same white color and alertness promoting effects offered by traditional blue-pump LEDs without the effects of blue at night. These lights boost alertness and productivity while eliminating the circadian disruption caused by the high nocturnal sensitivity of circadian rhythms to 440-490nm blue light after sunset.”
Alertness and Productivity at Night Safely Delivered
Light is energizing especially when it contains shorter wavelengths such as blue and violet. Some have suggested using blue rich light at night to prevent fatigue, but that produces circadian disruption and health risks. Zirc™ Night LEDs elegantly solve this problem by providing safe violet content, which is even more effective than blue at promoting alertness and productivity without disrupting our circadian clocks.
Evening or night-shift workers no longer need to dim the lights, or use low visual acuity orange-yellow lighting, to avoid the effects of blue-rich light at night. Spectrally engineered Zirc™ Day and Night light engines provide attractive energy efficient circadian healthy white light 24/7. As an added bonus the Zirc™ technology is ideal for 24/7 clinical observations of skin color with the Zirc™ Night 1.8 and Zirc™ Day 2.2 indices easily meeting the COI (Cyanosis Observation Index) requirement of <3.3.
About CIRCADIAN ZircLight
CIRCADIAN ZircLight is a member of the worldwide CIRCADIAN® group of companies, bringing health, productivity and safety solutions to the 24/7 business workplaces around the globe. Born out of breakthrough research on human circadian clocks at Harvard Medical School and the University of Toronto, CIRCADIAN has led in the transition of medical science breakthroughs including evidence-based circadian lighting into the 24/7 workplace. CIRCADIAN is unique in deeply understanding both the science, and the practical realities of 24/7 work. Visit us at www.circadianlight.com
About Acuity Brands
Acuity Brands, Inc. (NYSE: AYI) is the North American market leader and one of the world’s leading providers of lighting and building management solutions. With fiscal year 2019 net sales of $3.7 billion, Acuity Brands currently employs approximately 12,000 associates and is headquartered in Atlanta, Georgia with operations throughout North America, and in Europe and Asia. The Company’s products and solutions are sold under various brands, including Lithonia Lighting®, Holophane®, Aculux®, American Electric Lighting®, A-Light™, Antique Street Lamps™, Atrius®, Cyclone™, DGLogik™, Distech Controls®, DTL®, eldoLED®, Eureka®, Gotham®, Healthcare Lighting®, Hydrel®, Indy™, IOTA®, Juno®, Lucid®, Luminaire LED™, Luminis®, Mark Architectural Lighting™, nLight®, Peerless®, RELOC® Wiring, ROAM®, Sensor Switch®, Sunoptics® and Winona® Lighting. Visit us at www.acuitybrands.com
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