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26 Jul 2018, 13:52

Discover more about Human Centric Lighting at LEDVANCE - The right light for health and well-being

Why is Human Centric Lighting so important?

More and more people have to keep up with high demands at work and often also in their private lives and still want to feel comfortable doing so. An increasing number of companies and organizations are therefore prepared to invest in the health and well-being of their employees as factors for economic success. Here light can make a valuable contribution because for thousands of years important biological processes in the human body have been geared toward living in the natural light. The right light at the right time can create a lot of positive effects – for all age groups and in many areas of life.

The human organism needs what it originally got from the sun: bright light with a high blue component in the morning and throughout the day, and less intense, yellowish-reddish light without these blue components in the evening. Many people do not experience these natural changes of light often enough because they spend most of their time indoors. Artificial indoor lighting mainly helps to improve vision because it has been designed for that purpose in line with valid standards, but it is less biologically effective.

A human-oriented lighting concept – known as human-centric lighting (HCL) – uses smart controllable LED lighting systems to simulate the characteristics of natural daylight, giving something back to us that we often lack indoors. Field studies show that all age groups can benefit from HCL solutions – from students to seniors. Because of all these opportunities experts at LEDVANCE see an urgent need for greater clarification on biological lighting effects.

What do we need and how can we achieve it?

Evolution has geared important biological processes in the human body toward living with a natural day/night cycle. This particularly includes bright light during the day and darkness at night, which is why we need daylight or comparable artificial light as a regulator for our internal clock, just like our ancestors' thousands of years ago.

In the morning, the sensitivity of the photoreceptors in the eye that react specifically to the blue components in light is at its highest. Therefore a wake-up light (light alarm) slowly increasing in brightness helps us to be alert faster. Bright daylight-white light at the breakfast table promotes activity and performance and hence also the feeling of well-being for a good start to the day. This helps our internal clock to "synchronize" with the outside world and to adjust the body to "daytime mode".

During the day, bright light with a high blue component can increase concentration and also have a positive impact on our mood. To achieve these effects the light has to reach a certain brightness level. Outdoors, we get high illuminance levels of 10,000 lux even on cloudy days. By comparison, normal indoor lighting levels today are between 50 and 100 lux in homes, and around 500 lux in offices. If we want to maintain concentration and alertness as much as possible throughout the day, we need a significant increase in the light intensity that is normally found indoors. This mainly refers to the biologically effective blue components in the light. Bright light during the day also means that we are less sensitive to disturbing light stimuli in the evening or at night, provided we received a sufficiently high dose of light during the day.

In the evening, at least two hours before bedtime we should only use warm white (yellowish/reddish) light with relatively low brightness. This allows us to gradually wind down and relax, which is reinforced by the uninterrupted increase in the sleep hormone melatonin in the blood. Bright or cold white light with high blue components should, therefore, be avoided in the evening. It is important to slowly lower our alertness and vitality in the evening. That applies to lighting both in the workplace and at home. At night it should be as dark as possible.

What would be ideal HCL lighting?

Lighting based on the latest scientific findings that address the needs of people is defined as “human-centric lighting” (HCL).

When planning an ideal HCL concept, both the visual effects of light (for better vision) and the non-visual biological effects of light must be taken into account. Generally, the following principles apply:

  1. The more natural light that is used, the better.
  2. Smart HCL solutions should automatically be oriented to the changes in natural daylight in terms of light colours, brightness and the spatial distribution of the light.
  3. People are especially receptive to the biological effects of light in the first two hours after getting up and at least two hours before bedtime.
  4. Large lights from above that imitate a sunlit (blue) sky have the greatest biologically activating effect. Therefore, at the start of the day until lunchtime and after the lunch break, bright, cold white light with a high blue component (such as 6500 Kelvin at an illuminance of 300 lux at the eye) should be used. Indirect light which includes both ceilings and walls is ideal for this.
  5. Towards the evening the lighting should be changed to direct warm white light without blue components (such as 2700 to 3000 kelvin) to help our bodies to relax and prepare for the night.

Click here to find out more about the HCL study at


a.zanin has not written a bio yet…

26 Jul 2018, 13:52


August 3, 2018 07:40

very informative article

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