The Fifth Generation of Light has Arrived

Healthy lighting that recreates the blue = day, no-blue = night signal of natural day and night is now available to keep our circadian clocks robustly synchronized

Today I am excited to announce the arrival of the Fifth Generation of Light. These are electric lights that promote health and well-being by automatically switching between blue-rich daytime light and zero-blue light at night, without requiring large changes in brightness or correlated color temperature (CCT). These Lumium Circadian Blue lights are introduced by Korrus, and are on display at the LEDucation show in New York on March 19^th, 2024.

Korrus Lumium Circadian Blue Light spectrum for day and night

The History of Light Exposure

The history of human exposure to light is coming full circle with the arrival of circadian lights.

The First Generation of Light

For the first 10,000 generations of human existence, our ancestors were bathed in blue-rich daylight and slept in the dark at night. This alternation between bright blue-rich daylight and the absence of blue at night is the key signal that keeps the 24-hour rhythmic processes of our bodies, called circadian rhythms, in harmony with the natural world.

The Second Generation of Light

250,000 years ago, humans first gained control of fire. Blue-free woodfires and candlelight (from 3,000 years ago) freed humans from the tyranny of night without disrupting our circadian rhythms – although they coated all interiors with soot.

The Third Generation of Light

In 1882 in New York City, Thomas Edison introduced the incandescent light bulb and this was followed by other low-blue electric light sources, which enabled us to conquer the night – but they were inefficient in the use of energy.

The Fourth Generation of Light

2014 was the start of the widespread adoption of ⁓ 450 nm Royal Blue pump LEDs which provided a twenty-fold increase in lumens of light produced per watt of electricity – but their bright blue-rich light came at an enormous cost to human health at night. Recently 248 leading circadian scientists called for LED lights to carry a warning label “May be harmful when used at night” because of the significantly increased risk of sleep disorders, obesity, diabetes, heart disease, and certain cancers.

The Fifth Generation of Light

On March 19^th, 2024, Korrus announced at the LEDucation show in New York City, the launch of Lumium Circadian Blue lights which automatically provide an effective dose of sky-blue light throughout the day, and a safe, non-disruptive, level of blue light at night. These provide the blue doses required for good health, while providing the high-quality white light day and night that we need to live and work by.

Why is it so important to control sky-blue light wavelengths?

Out of all the rainbow colors of the natural light spectrum, a narrow band of sky-blue light between 440-495 nm provides the key signal to our circadian clocks that it is day, or it is night. These blue wavelengths are 25 times more effective than the other color components of the white light spectrum in resetting circadian clocks because they are detected by blue-sensitive melanopsin-containing cells in the retina of our eyes.

Sky-blue light during the day synchronizes and strengthens our circadian rhythms. But after the sun sets these same blue wavelengths disrupt our circadian clocks – because they give the false signal that it is daytime and not night.

The irony is to save the health of the planet, the Department of Energy has been promoting blue-pump LED lighting that harms human health when used at night. In 2013, LEDs comprised only 1% of lighting sales, but by 2024, LEDs were in over 70% of all lights sold worldwide. Low-blue light sources like incandescent and halogen bulbs are now banned, and until today the only lights readily available have been ⁓450 nm Royal Blue pump LED.

Development of Evidence-Based Circadian Lighting

Our discovery that most of the circadian impact of light fell within a narrow band of 440-495 nm sky-blue wavelengths made possible the design of white LED light that was either blue-rich or blue-depleted. A key breakthrough was our finding that we could create an attractive warm white light for evening and night use, by replacing the blue LED chip with a violet LED chip in the 415-425 nm range. The human eye responds to violet for only the first hour after nocturnal darkness, but once our eyes are fully light-adapted violet light has minimal effects on circadian clocks for the rest of the waking day. So, by using a violet LED chip, we could balance the color spectrum in the absence of blue light and create a light with an acceptable warm white color.

Over the past 10 years, we have demonstrated the benefits of circadian lighting in controlled studies with human volunteers in the Circadian Light Research Center we built on Boston’s Route 128 high-tech corridor. Then, over the past 5 years, we have studied the efficacy and safety of circadian lighting installed in 65 safety-critical workplaces including Chevron, Dow Chemical, US Coastguard, Duke Energy, and National Grid.

Circadian Light Research Center

In the controlled environment of the Circadian Light Research Center, we showed that there were substantial benefits to using blue-depleted circadian lights during the evening and night hours as opposed to conventional blue-enriched LED lights.

• Total Overnight Melatonin production was significantly increased under blue-depleted circadian night lights. With <2% blue lights at night over six times more melatonin was produced between 8:00 pm and 8:00 am compared to conventional blue-rich LED lights at the same illumination intensity. We can reasonably conclude that the multiple benefits of nocturnal melatonin in suppressing cancer cells, and supporting healthy metabolism and immunity are protected and enhanced by low blue lights at night.

• Glucose Intolerance and Insulin Resistance were prevented by blue-depleted lights. With nighttime exposure to conventional blue-rich LED lights, insulin resistance was doubled, rendering the healthy subjects into a pre-diabetic state.  In contrast, blue-depleted circadian night lights prevented the pre-diabetic condition, even though both lights were at the same illumination intensity.

• Increased Appetite induced by blue-rich LED lights at night was reversed by the blue-depleted circadian night lights. This increased appetite leads to more snacking on the night shift and the excessive obesity too often seen in night or rotating shift workers.

• Circadian Disruption was prevented by blue-depleted lights. Conventional blue-enriched LED lights during an overnight study delay-shifted the peak of melatonin. This disruption in circadian timing was reversed by the blue-depleted LED lights at the same illumination intensity.

• Vigilance Performance was improved by the blue-depleted violet pump circadian night lights. Conventional blue-pump LED lights increased vigilance performance, but not as much as the violet-pump circadian night lights. And the circadian blue-depleted night lights improved performance without causing all the other undesirable effects of blue-enriched LED light at night.

Installations in Fortune 500 workplaces

We conducted one-year follow-up studies comparing the previous conventional fluorescent or blue pump LED lighting with the circadian day-night lighting systems and demonstrated:

• Improved sleep duration and quality were shown both before and after night shifts in people working rotating shifts around the clock, as the circadian lights prevented disruption of the workers’ circadian rhythms.

• 50% reduction in excessive sleepiness was measured on the Epworth Scale, a well-established measure of daytime sleepiness.

• 100% increase in alertness at 5 AM –This is the hardest time to stay awake on night shifts when errors and accidents caused by inattention reach their peak.

• 45% reduction in the average number of snacks eaten during night shifts. This can lead to weight gain which is prevented by circadian lighting.

• 20% reduction in gastrointestinal disorders in people working shifts around the clock, because of reduced circadian disruption when low blue light is used at night.

• 67% Reduction in operator errors in people working in safety-sensitive control room operations controlling multi- billion dollar businesses.

• 43% Reduction in the use of Over-the-Counter (OTC) pain medications:

Korrus now brings this technology that we invented into the mainstream, so it can be widely available – first with the architectural lighting fixtures introduced at LEDucation, then automated circadian light bulbs, and next into the computer screens that we sit in front of all day.

We have truly come full circle as we enter the fifth generation of lighting.

To read more sign up for the 2024 print book edition of THE LIGHT DOCTOR: Using Light to Boost Health, Improve Sleep, and Live Longer at https://thelightdoctor.com/contact/