Our body interacts with solar radiation in many ways. Some of these interactions, such as vision, directly determine our experience – others, such as tanning or the warming of the skin, we can understand more indirectly.

In addition, there is a wealth of other often little-known effects and cascades of secondary effects that emanate from this interaction, such as the stabilisation of our bones and muscles, the timing of our inner rhythms, our mood, … and especially also the modulation of our immune system. The basis for this is the production of the body‘s own vitamin D, which begins when sufficient ultraviolet radiation falls on our skin. Vitamin D strengthens our immune response, but also helps to prevent it from getting out of hand and turning against our own bodies in the form of auto-immune diseases.

Since the intensity of radiation indoors is much lower than outdoors, radiation deficiency symptoms occur when we spend too little time outdoors. At the turn of the 19th and 20th centuries, widespread diseases such as rickets, but especially pulmonary tuberculosis, were treated with “air and light cures“. The recuperative cure in Davos, Switzerland, became known worldwide through Thomas Mann‘s novel “The Magic Mountain“.

photo © GNM / Dirk Messberger