Light for health and well-being – from the biological principles to policy


It has a profound influence on human physiology and behavior: Light at the wrong time, especially during our “biological” night, hampers production of the hormone melatonin. This disrupts our internal clock and affects the natural duration of our sleep. This extreme effect is due to special cells in the retina that were only discovered in the late 1990s: the so-called intrinsically photosensitive retinal ganglion cells (ipRGCs).

Since that time, new findings have revolutionized the evaluation of light in our diurnal and nocturnal environment. Insufficient exposure to light, for example, has been linked to the development of myopia and the suspected involvement of ipRGCs. To an increasing extent, new methods are now making it possible to determine when we humans require how much light.

This is reflected for example in building standards and in norms for light measurement and quantification. An international group of experts recently presented consensus recommendations as to what light intensities are appropriate for daytime, pre-sleep, and sleep environments. Interest in the positive and negative effects of light ranges from the fields of neuroscience, architectural lighting design, and the development of new lighting technologies, to the implementation of political measures. One example is the Science and Technology Committee of the British House of Lords, which has conducted an analysis of the effects of light on human health.

Overall, there is a great need for interdisciplinary exchange, in order to develop new strategies for the optimized utilization of light for health and well-being. The Ladenburg Roundtable, under the management of Prof. Dr. Manuel Spitschan from the Technical University of Munich and the Max Planck Institute for Biological Cybernetics, will bring together experts from these fields.