The normal light of the sun affects the human organism in many different ways. Among other things, daylight synchronizes the inner clock and thus determines the production of the hormone melatonin, which is partly responsible for the quality of sleep. “Responsible for these non-visual effects are light-sensitive ganglion cells in the retina of the eye,” the scientists explain.
Researchers from the University of Applied Sciences in Munich investigated how different light situations affect the cognitive performance of individuals. They found that certain light signals have a direct effect on the autonomic nervous system, sometimes causing undesirable effects. With the right light at the right time, work performance can be enhanced. The research results were recently presented in the renowned journal “PLOS ONE”.
Those who provide an optimized lighting environment can achieve the same performance with less effort. A Munich research team came to this conclusion during tests in the light laboratory. The findings provide new perspectives, especially for the working world.
Good lighting conditions mean less effort
The ganglion cells contain the protein melanopsin, which is sensitive to blue light. “Depending on the direction, intensity and spectrum of the light, these cells send signals directly to the autonomic nervous system, the control center of the body,” the researchers say.
How daylight affects the body
But not only sunlight, but also artificial lighting affects these cells. According to the research group, artificial light is currently used in a completely unplanned way and often leads to undesired side effects that have so far been hardly noticed. Modern LED lighting can be easily adapted to produce the right light at the right time.
In the current study, the research team illustrated the effects of incorrect lighting at the workplace. In the light laboratory, the scientists examined the cognitive performance of 27 test persons in three different light scenarios, each in the morning and afternoon. In all cases, the lighting corresponded to the current EU standard for artificial lighting of interiors with a brightness of 500 lux on the work surface.
During the experiments, the intensity, light spectra and direction of irradiation of typical neutral-white LED lights were varied. For example, a cool-blue light from above with 7000 Kelvin simulated a bright morning. For the evening setting, an intensity of 2700 Kelvin was selected and the red light color was subdued. The Kelvin value indicates whether a lamp emits warm or cool light. The higher the Kelvin value, the cooler the light appears.
The participants went through three different light scenarios in random order in the morning and afternoon. During the ten to fifteen-minute exposure time, the test subjects had to complete a memory test. The error rate and reaction time were measured. Changes in the heart contraction time (PEP) were also recorded. This value reflected the effort the participants had to make to achieve the required performance.
“We found that a typical light environment in the working environment leads to greater effort for the test subjects,” summarizes Johannes Zauner from the research team. It is more recommendable to regulate the lighting conditions based on natural times of day in order to support the circadian rhythm.
As the research group reports, the test persons reacted to the respective light after a short irradiation period. Both in light that was modelled on natural morning light and in simulated evening light, the participants’ exertion decreased while their performance remained constant. However, with typical light settings, such as those found in most offices, the measured effort increased by up to two percent.
WashingtonNewsday Health and Wellness.