A recent ground swell of interest in the effects of lighting on human well-being is driving significant research. Extensive studies are showing that proper lighting can greatly enhance our indoor lives. In fact, in 2017 a group of scientists were awarded a Nobel prize for identifying the mechanisms that control our Circadian Rhythm and the role lighting plays in triggering those mechanisms.

An absence of light from the blue end of the visible spectrum during the day causes disturbances to our natural Circadian Rhythm. Too much light from the blue end of the spectrum at night also causes Circadian Rhythm interference and can have negative impacts on sleep patterns. Optimal synchronization of lighting at the proper times of day helps to regulate our bodies. However, if proper lighting cycles are not maintained, our normal sleeping and eating cycles are negatively impacted and we will be hungry, alert or sleepy at the wrong times of the day. This disruptive impact to our natural clocks can lead to significant health issues such as Diabetes, Depression and even Cancer.

There is also substantial research being conducted that indicates the profound benefits of Human Centric Circadian Rhythm LED Lighting within the senior living facility environment. Initial results indicate that use of Healthy Circadian Rhythm Lighting throughout the facility makes residents more alert during the day, sleep much better at night and experience overall improved well-being and quality of life. This result is clearly best achieved through lighting rather than the use of drugs. Although senior living facilities are currently one of the applications where the health benefits of proper lighting are most profound, many other environments are recognizing the benefits as well.


The Moscow Metro has launched a new generation of trains featuring Led Lights that adapt to the time of day.

Commuter trains on Moscow’s busiest route now feature a cold tone of tunable Human Centric LED lighting in the morning and a warmer shade in the evening. This is consistent with Circadian Rhythm Lighting research that indicates that cool blue spectrum lighting in the morning, which is higher on the Kelvin scale, helps suppress Melatonin and activate Cortisol which helps the body be more alert and energetic. This leads to increased alertness, productivity and well-being on the job for the commuters. The warmer lighting in the evening, which is lower on the Kelvin scale, creates the opposite effect, promoting Melatonin production and reducing Cortisol production leading to a more relaxed state that prepares the body for quality sleep later in the evening in lock step with the bodies normal Circadian Rhythm.


A report commissioned by LightingEurope, an industry trade group, calculated office productivity increases equivalent to about two more hours per month, a decrease in sick days of one percent and an increase in employment duration of one year because of tunable LED lighting. (They found greater benefits in the industrial setting)

In another study of daytime light exposure on office workers, employees receiving high levels of circadian-stimulating light during work hours had more stable circadian rhythms, as well as lower levels of depression and greater sleep quality, compared to employees receiving lower levels.

The installation of ‘human-centric’ lighting at the office of the property company CBRE has boosted productivity by 18 per cent. Additionally, work accuracy improved by 12 per cent, 76 per cent of employees reported feeling happier and half felt healthier. The findings by scientists from the Twente University, The Free University Amsterdam will be seized on by the lighting industry as long-awaited hard evidence that investment in dynamic lighting gives a tangible return.


Circadian Rhythm LED lighting also has a positive impact on athletic performance.

The Seattle Mariners were the first major league team to implement the Circadian Rhythm lighting system in their locker room in 2013. They were able to benefit from utilizing brighter cool white lighting before games. The bright white high Kelvin lighting increases alertness and energy.

Warmer low Kelvin settings following games helps to relax the team and regain energy for their next game or practice. “When you’re in sports, you’re looking for every advantage you can get to improve performance,” said the team’s former facilities manager, Scott Jenkins, who also worked with the Atlanta Falcons of the National Football League. Tunable Human Centric LED lighting was also installed in the Falcons facilities. Other professional teams including the Portland Trailblazers, Denver Nuggets, and New York Yankees have also followed suit and many more are considering it.


According to Harry Zuker, CEO of Walalight LLC, a leading manufacturer of Healthy Circacadian Rhythm LED Lighting,  “There are significant benefits to the use of Tunable LED Lighting in the classroom environment, Sleep deprived students are prompted to produce Cortisol due to the bright white 5000 Kelvin lights used in the morning. Students are relaxed and their bodies release Melatonin when the lights are adjusted to 3000 Kelvin later in the day. This helps with many physical and behavioral issues. Students also experience better visual acuity and cognitive performance. Positive improvements in motivation and focus are also seen.”

Studies have demonstrated that using light with a higher blue content will shrink the size of the pupil which leads to higher visual acuity. There is a distinct correlation between pupil size and reading performance driven primarily by light spectrum and not brightness. This can be explained by a photo receptor recently discovered in the eye called the pRGC.

Other studies have demonstrated that light in the blue spectrum (short wave length light) will trigger cortisol production in sleep deprived adolescents. Adolescents need more sleep than adults, but they live on an adult schedule. The result is they tend to arrive at school less prepared for the day. Researchers have concluded that exposure to light in the blue spectrum in the morning will better prepare adolescents for the day ahead. It will help with preparing the body for activity and stress response.


A well-lit indoor space during the day can help maintain a normal Circadian Rhythm. In the fire station environment where a normal sleep schedule is regularly interrupted, Circadian Rhythms can fall out of synch, which may cause problems with concentration, alertness, and overall wellness.

Providing quality daylight balanced with appropriate warm light and darkness at night can help regulate the Circadian System leading to improved mental health and increased readiness. Human Centric Lighting can decrease stress and have a calming effect on the occupants of a building. Properly designed LED lighting can help support the wakefulness of occupants by creating lighting that does not disturb the hormonal melatonin response of the Circadian system. This can be done by creating light at night that is emitted at certain non-intrusive wave lengths (typically toward amber light) and by creating quality darkness for restful sleep.

All the benefits of proper lighting are vital to the firefighters who must be alert at a moment’s notice. Additionally, improved health of fire station occupants can mean a reduced cost in insurance premiums to the municipality and fewer accidents so that the fire station performs better.

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Harry Zuker
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