Us, as humans, have a unique way to know when we are tired and when we need to hit the hay. Our bodies are able to communicate with our brain and release a chemical called melatonin (you’ve probably taken it as a supplement for your insomnia) to help get to sleep soundly. This process is known as our body's circadian rhythm. This rhythm is affected by light; natural and artificial.
Naturally, our circadian rhythm is affected by the sunlight. We know it’s time to wake up in the morning with the sunrise, and we start to get tired with the sunset. This is how our sleep cycles are affected. However, with the artificial light that we consume daily, our circadian rhythm can be affected negatively. The more artificial light consumed, the more our circadian rhythm will be offset making it harder to fall asleep or have a normal sleep schedule (and it's hard enough as it is).
“ People in the developed world today spend, on average, 90 percent of the day indoors and often out of eyeshot of a window” — Undark, 2018
Did you know that inhabitants of cities have more issues with their circadian rhythm? Light pollution negatively affects the cities’ inhabitants with a hoard of health issues from forms of depression to brain, eye, and internal rhythm deterioration. Circadian lighting is a new way of consuming light that mimics natural light as a way to combat these sleepless nights that plague many today.
Scientists state that our “physical drumbeat” is “disrupted to ill-effect by our constant exposure to standard incandescent or fluorescent lighting — and more recently, to the relentless glow of electronic screens” — U.S. DOT, 2015
By replicating sunlight, our body's biological clock will be reset and changed for the better, resulting in an improved sleep schedule and healthy day-to-day life.
What Exactly Is Circadian Lighting?
Circadian is a new way of lighting to mimic sunlight, and our natural circadian rhythm. It works by changing the lighting throughout the day, changing its color, and intensity to help bring a more stable, sleep/wake cycle (The Lighting Practice).
Circadian lighting uses 3 different methods to mimic sunlight, intensity tuning, color tuning, and stimulus tuning:
● The first method is intensity (brightness) of the light, which also happens to be the most cost-effective and popular one. For instance, the light, like sunrise lighting is subtle, growing in intensity throughout the day and reaching its peak hours of intensity, then falling again. This lighting is dimmable and is able to be manipulated this way, with lower intensity at night.
● Color tuning of the lighting matters as well, which means being able to change from warm and subtle, to white and bright. The correlated color temperature (CCT) and the intensity, mimic the day/night cycle. CCTs for cooler temperatures (4000K to about 10,000K) are when the sun is highest in the sky and people are the most alert. Warmer color temperatures (appox. 2700K-3500K) simulate the sun rising and setting, for a more relaxed reaction to the lighting. An example of this is the implementation of color tuning by Apple with the Night Shift feature that minimizes blue screen light at night.
● Lastly, stimulus tuning is changing the wavelength to a good blue light that more closely resembles that of natural circadian lighting. This is paired with dimmers from intensity tuning for the most effective approach in reducing blue light waves at night.