Light is particularly important for the human organism. This is noticeable above all during the dark winter months when there is less daylight – which often leads to depressed moods. Even a long working day under artificial light can have a tiring effect. The less daylight there is, the more the light levels drop at the workplace and hence the ability to concentrate. Science has found solutions for this, which are now also being applied in practice.
The colour of the light plays an important role for the day-night rhythm of humans. So-called photosensitive ganglion cells are found in the retina of the eye, which transmit the information absorbed by the eye to the brain. Light in the blue area of the visible spectrum can be absorbed particularly well by the cells. Blue light leads to a reduction in the production of the sleep hormone, melatonin, which means we stay awake longer and can concentrate better. Conversely, red light leads to the body preparing itself for the resting phase and sleep.
Lighting influences biorhythms
How these findings can help in the daily work routine is shown by the example of the Festo Technology Plant in Ostfildern-Scharnhausen. There, in cooperation with the Fraunhofer IAO, a health-promoting lighting concept has been implemented. It is based on natural solar irradiation, which, over the course of a day, shifts from cool, blue to warm, red light.
Production employees who work in shifts thus find the right light intensity that corresponds to their natural biorhythms for the given time of day. Thanks to the increased red light towards the end of the day, the workers thus find it easier to sleep at home after the late shift.
Besides the colour of light, the brightness can also have effects on the human organism.
Dr. Max Kaplan, President of the Bavarian State Medical Association and former GP, for example, deals with this phenomenon. According to Dr. Kaplan, a consistent level of brightness has a positive effect on concentration at the workplace. For this reason he had around 700 LED pendant lights installed in the Munich offices of the State Medical Association. These provide a consistent brightness of 500 lux to all workstations and at the same time consume much less energy than conventional lamps.
The principle is simple: as soon as it get brighter outside, the LEDs shine less brightly, whilst they are intensified by control systems when it gets darker.