The Asprey Advent Calendar of Savings has Arrived!

Circadian Light: What Is It & Why Should You Care?

Image of open work space

Article at a Glance: 

  • Light directly impacts our visual and non-visual responses.
  • When we don’t get enough exposure to the sky-blue region during the day, and/or if we get too much exposure to wavelengths in this region at nighttime, we are at risk of experiencing circadian rhythm disruption.
  • Poor lighting can negatively impact mood, energy, focus, and productivity during the daytime. It can also affect your sleep later at night.
  • Circadian lighting is a healthy alternative to conventional LEDs and fluorescent light sources.
  • There are three ways to implement a circadian lighting system including intensity tuning, color tuning, and stimulus tuning.

Light is the most powerful synchronizer for the human body clock, as it affects both our visual and non-visual systems. And while this clock is deeply engrained in our biology, many experts argue that more time indoors under artificial light and in front of digital screens can throw this natural rhythm off-center.  Research indicates that circadian rhythm disruption is associated with a wide variety of adverse health consequences, including but not limited to increased risk for premature death, cancer, metabolic syndrome, cardiovascular dysfunction, immune dysregulation, reproductive problems, mood disorders, and learning deficits. (1)  Circadian light is a healthy alternative to conventional lighting that offers a real solution for improving mood, performance, and well-being.

What is “circadian light”?

The concept of circadian light stems from the human body’s natural body clock, aka your circadian rhythm, which operates on approximate 24-hour cycles.  Unlike conventional junk light – artificial light from LEDs and fluorescents — circadian lighting is scientifically designed to emit specific wavelengths that help regulate your circadian rhythm. This technology is sometimes also referred to as Human Centric Lighting (HCL) or wellness lighting.

How does circadian light work?

There are three ways to implement a circadian lighting system: intensity tuning, color tuning, and stimulus tuning.

Intensity tuning involves maintaining a fixed correlated color temperature (CCT) and adjusting the intensity (brightness) of the light through a controlled dimming system. This gives you the ability to transition between lower lighting intensity in the early morning, higher intensity as the day progresses, and the lowest intensity in the evening.

Color tuning involves adjusting the CCT to mimic the natural oscillations between light during the daytime and darkness at night. During the daytime, when the sun is at its highest point in the sky, we experience cooler color temperatures (from 4000K–10,000K). This is typically when we feel most alert. So, cooler CCTs are most effective to use in designated spaces (and at certain times) when you need to feel energized and focused. Warmer (redder) color temperatures (from 1000K–3500K) more closely represent what we experience when the sun rises and sets.

Stimulus tuning is a lighting technology that emits light in your circadian system’s peak sensitivity region (near 490nm) (2).  It essentially replaces the “bad blue” that can cause retinal damage with “good blue” light wavelengths that entrain circadian responses.  Stimulus tuning fixtures can be programmed with dimmers to either infuse or minimize the amount of blue light they emit depending on the time of day.  That means you can proactively transition between promoting alertness in the daytime and preparing your body for sleep at night.

Which circadian light system is the most effective?

Truly circadian light systems infuse the sky-blue region of light (near 490nm) to pinpoint key photoreceptors that regulate your mind and body. They essentially mimic the circadian benefits that you would otherwise get from natural sunlight if you were outdoors.  So, in choosing circadian lighting for your home, office, or other building, make sure that the bulbs specifically emit sky-blue light during the daytime. If they have a nighttime setting or dimming capability, you want bulbs that completely remove all blue light to prompt nighttime signals and prepare your body for sleep.

Why is circadian lighting important?

Studies show that insufficient or inappropriate light exposure can disrupt the body’s biological rhythms which can have adverse consequences for performance, safety, and health. (3) Remember, not all blue light is bad; critical sky-blue light helps entrain your circadian rhythm, boost energy and improve mood during the daytime. At night, keeping your bedroom dark is essential for preparing your body for sleep.  Circadian lighting can help us maintain these natural oscillations between light and dark while also allowing us to live in harmony with modern technology.

What applications can circadian lighting be used in?

Circadian lighting can be used virtually anywhere, but it may be most effective for the following applications:

  • In your home
  • Office buildings
  • Hospitals
  • Restaurants
  • Nursing Homes
  • Gyms
  • Malls



You might also like...