What Is Human Centric Lighting?

Lighting as Nutrition: Is Your Light Good for You?

For the past 150 years, artificial lighting’s primary focus has been on providing enough light to be able to see objects with our eyes.

Modern research suggests that our bodies rely on light for far more than just vision. From regulating our sleep cycles to signalling seasonal changes, our bodies and health are far more receptive to light than we previously believed.

The same way we consider different foods to have different nutritional benefits and risks, it is important to have an understanding of what’s in your lighting and how that can affect your health.

The 4 Fs of Lighting Health: Fullness of Spectrum, Function, Flicker & Focus

Generally, three aspects of artificial lighting can have an effect on your health: fullness of the light’s spectrum, light flicker, and distribution/focus of light distribution. For each of these aspects, the goal is to achieve a lighting effect that most closely resembles natural light.

1. Fullness of Spectrum: Natural daylight has all of the visible wavelengths present. The Colour Rendering Index (CRI) is a quick way to evaluate a light source’s fullness of spectrum. A healthy LED light should have a high CRI rating of 95 or more to most accurately mimic the spectrum of natural light.
2. Function: Consider the function and purpose of the lighting system and choose a colour temperature accordingly. For light therapy, choose a colour temperature of 5000K or higher to replicate mid-day sunlight to promote alertness. To limit the impact of blue light during evening hours choose a colour temperature of 2700K or lower.
3. Flicker: Many artificial light sources flash on and off at very high speeds that are not generally visually perceivable but can have detrimental health effects. The sun provides constant brightness and it is therefore necessary for a LED bulb to not exhibit such strobing. Look for LED lights with a flicker percentage of 5% or lower and a flicker index value of 0.02 or lower.
4. Focus: We don’t usually think of it in this way but the sky is a huge dome of natural light that shines down on us. Artificial narrow focus lights with high levels of glare do not resemble the diffused and broad light that shines down on us during the day. Consider using a higher number of low brightness bulbs, or lighting techniques such as wall washing to achieve a similar effect.