Light and lighting technologies are constantly changing. In this way, light becomes more and more valuable and we continue to experience new advantages that light sources can bring. As we have discussed in previous blogs, we see that lighting achieves ever greater efficiency and thus saves energy. In addition, other applications of light are being discovered, such as internet via light.

Our bodies are very dependent on light. There is a lot of research going on nowadays on the effect of what light does to our bodies. These studies focus on the effects on our emotional well being, health and work efficiency.

The human body is used to the fact that light changes over the course of a day. For example, the daylight in the afternoon has a different colour and glow than in the evening or morning. By recognising these colours of the daylight, our body knows where it stands. An interesting development in the world of lighting is Human Centric Lighting.

What is Human Centric Lighting?

Human Centric Lighting focuses on the well-being, comfort, health and productivity of people by simply adjusting the light color and intensity during the day to suit the body's needs.. In a way, this is a form of light therapy.

In the 90's there was a lot of experimentation with light therapy. Scientists discovered that people have more energy in the summer, are less prone to irritation and are in a better state of mind compared to the winter. This of course has everything to do with the number of hours they are exposed to sunlight. For example, there are people who experience a lot of trouble when the seasons shift. Seasonal Affective Disorder, or seasonal depression (winter depression), is what we call this phenomenon. This phenomenon often occurs when a person who is sensitive to it, does not have enough contact with daylight. In order to prevent this, the person in question must be exposed to daylight as much as possible. Because we have less daylight in winter and because some people work and live in locations where they can receive little sunlight, we can imitate the sun by means of LED lights.

Effect of light temperature on the human body

Light has a major influence on the daily rhythm of the human body. The most important effect that light has on the body is that it regulates melatonin production. Melatonin is also called the sleep hormone. It causes us to get tired. Cold white light (6000K) suppresses the production of melatonin.

In 2002 scientists found out that there are cells in the retina that have nothing to do with human vision. These cells do catch light to keep our daily rhythm in order. These cells are most sensitive to blue light. Blue light keeps us awake and makes us more alert and attentive. This increases our ability to concentrate, for example. By using cold light in working environments, work efficiency can be increased.

Effect of light intensity on the human body

Light in the blue spectrum can thus suppress the production of melatonin. However, there must be enough blue light in the blue spectrum to allow this process to run smoothly. Research has shown that the suppression of melatonin production by cold light already has an effect from an illuminance of 30 Lux at eye level. More than 1000 Lux at eye level will saturate the effect.

In order to keep the daily cycle optimal, it is important that we see the right light temperatures. Cold light makes us less tired. However, it is not advisable to have cold light on all day. This disrupts the daily cycle by simply postponing it. The body will have to relax at some point. It is therefore advisable to use cold light in environments where higher alertness and concentration are required. Think of workplaces. When high alertness and concentration are not needed, the body should be able to relax. It is best to use warm light at these times. Think of work breaks and evening light.

More about the use of light colours can be found in this blog:
What is the right colour temperature for LED lighting?