Licht für Gesundheit



Ahmet Cakir

„Light and Health“ seems to be an important issue. But why did the people discover it at the beginning of the 21th century?

I have found the review of a book, long forgotten, written by a well-known author, not forgotten, Luckiesh. This is the earliest book I could find for this issue. From the review, one can detect what Luckiesh and his co-author found to be important in the year 1926, daylight and natural radiation. In 1965, C.T Larson performed a study suggesting windowless schools because the only function left for windows was to view the outside, and this would distract the pupils. Collins cited him in 1974 „“At present the pro-window forces still lack behavioral data in support of their case and argue on the basis of metaphor and supposition, but their arguments must be weighed against statistics… from the windowless schools …reported to have 40 percent greater efficiency in heating and cooling, constant light to prevent eye strain… 35 decibels or more noise reduction, and reduced maintenance costs.” But half a century ago, Luckiesh had demonstrated why natural radiation was important for health, and that windows would not allow the most relevant part of it, UV radiation, to enter the buildings.

I think, the main culprit is the definition of light. In lighting engineering, light is the part of the electromagnetic spectrum that serves vision while in other sciences, light is „optical radiation“. Luckiesh considered light in this sense. What is the difference? Architects like Larson and even experts for occupational medicine have been mislead by the term light. E.g., a congress for occupational medicine gave its blessing: During the 6. Congress of the German Society of Occupational Medicine 1965, dedicated to the “windowless workspace”, it was questioned whether one could investigate all aspects of windowless work environments, however it was stated: “Humans in windowless work rooms do not have to fear health impairing impacts of the environment as long as that environment is optimal from the point of view of work hygiene.” (from Batzel, 1989).

Obviously, the experts of occupational medicine did not consider that natural light could be a factor of work hygiene. Moreover, one of the most prominent persons among them considered windowless work environments a „dream“:

“The introduction of fluorescent lamps has made it possible to realize two dreams of
technology, namely working in windowless and precisely air-conditioned rooms on the one
hand and daytime-independent machine operation on the other.” (Schober, 1961)

Well, I think he was acquainted with Luckiesh personally, and even if not, he should know what he was talking of.

Here is the review of the work by Luckiesh and Pacini (to read the original work by Larson, please click here)

Light and Health-By M. Luckiesh and A. ,.
Pacini, Directors, Research Laboratories,
General Electric Co. Baltimore: Williams
& Wilkins Co., 1926. 302 pp. Price, $5.00.

This work reads .. like a romance in science,“ although limited to the field indicated by the title. The senior author is well known to us as a leading illumination authority while the junior author’s name occurs much in present day professional journals. Both have contributed freely in the present ·book from their own discoveries. The preface states that the book is founded upon data which appears to be well established and suggestive, as well as correlating the physical and biological viewpoints. The material is presented as free as possible from technical terms for general readers, health officials, and scientific men not specialized in the subject. The work has evolved from the fact that controllable radiation, or .. radiant energy,“ or .. light,“ has been discovered.

Solar radiation has been a powerful environmental factor in the evolution of life which has culminated in the human being. Apparently radiations of certain wave lengths are as essential as oxygen to the health of biological beings including man. An enormous amount of data and theory have appeared on the subject ‚and the authors seem to have made a wide and commendable selection, particularly if the reader keeps in mind that they often find themselves on the border of the unknown and even beyond the regions of conjecture.

The fifteen chapters discuss, in order, the nature of light and radiation, climate and the human race, light and the origin of life (its relation to chlorophyll in the plant and to hematin the animal’s ,blood); the relationship of light to blood, to the skin (sunburn, pigmentation, disease), the glands (personalities, old age and rejuvenation), the skeleton, the muscles, the nerves, the viscera; to infection and hygiene; to the special senses; the psychological . effects of light; and the subject of lighting for health and happiness (near-sightedness,. glare, eyestrain, production, fatigue, and safety).

From the first page the style and subject matter prove entrancingly interesting. It is clear  that at times the speculative is not differentiated from the factual and also some of the discussions leave one in doubt as to whether the authors‘ optimistic interpretations are safe. Still, the work proves a true stimulus to thought and speculation even to the most unimaginative. Valuable graphs, tables, and cuts of spectra, as well as numerous illustrations of the effects of light upon the body and the methods of its application for different purposes are given. Naturally, the greater part of the discussion concerns the theme of the day, ultraviolet light, although the entire subject of radiant energy,“ from the long infra-red to the gamma rays of radium, are discussed. Nor, while discussing man’s triumphs with artificial light as a substitution for sunlight, do the authors belittle the omnipotence of sunlight and daylight, though they emphasize its feebleness in ultraviolet“ for many days of the year, especially in northern climes. One can often pick statements that are too comprehensive, such as „Blondes always burn; brunettes always tan. The exceptions are too few to comment upon.“ Inconsistencies occur, such as (p. 258) „the case seems reasonably strong against ultraviolet radiation as one of the possible causes of cataract,“ whereas (p. 262), if this is repeated too often, opacities develop in the lens ultimately producing cataract. Repetitions occur but, the reviewer thinks, only pleasurably and enough to emphasize. An error occurs here and there, but the book shows the marks of much thought and high class modern press work. The authors use the Angstrom unit which places most of the wave lengths discussed in thousands in contrast to the English writers who use the milli-micron unit and thus talk in hundreds-numbers perhaps more easily negotiated by the reader.

It is probably not going too far to say that almost every imaginable relation of light to the health of the human body and its organs and parts is discussed with a representative but not overweighed consideration of disease relationships, but all perhaps too optimistically. We must bear in mind that the vast part of the human race has spent most of its time out-of doors, that such existence, as illustrated by the present life of the natives of India which is said to average only 25 years as against our 55 years and more „indoorness,“ has not immunized the race materially against many infections, and that many believe the subject of diet is of equal importance to light, etc. Also as Dr. Dixon says, there must be some good reason why we tend to avoid even too much sunlight. The names of many investigators are mentioned though no bibliographical references are given, which is probably allowable in a book of this nature.

The index is woefully abbreviated, but is not a Table of Contents showing chapters enough in a good recital well told? The writers have done an excellent piece of work in their attempt to popularize a mass of scientific data and show that „truth is stranger than fiction.“ Is the scientist perhaps to become the popular writer of the day with his ‚Vade mecum?


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One comment on “Whodunit?

[…] Warum aber diese Feststellung in einem Lichtblog? Hat Licht was mit der Wahrheit zu tun? Die schnelle Antwort überlassen wir den Esoterikern. Die werden je nach (Un)Glaubensrichtung die passende Formulierung schon finden. Mir geht es um die Physik. Immer wenn jemand von gesundem Licht spricht und künstliches meint, gehen mir die Nackenhaare hoch. Der müsste es doch wissen. Oder? Dummerweise nicht. Denn die Lichttechnik hat sich bereits in den 1920ern von der Wahrheit über Licht verabschiedet. Für sie ist Licht, was dem Sehen dient. Die „heilige“ Kurve, die sog. V(?)-Kurve berücksichtigt weder UV noch IR, obwohl beide unerlässlich sind für das Leben auf Erden. (Vielleicht nicht in der Tiefsee. Da gibt es Würmer, die sich an heißen Schwefelquellen laben.) So lange wie sich Menschen einigermaßen natürlich verhielten – also rin in die Bude, raus aus der Bude – und einen Teil ihrer Zeit draußen verbrachten, ging die Sache gut. Innenräume mit künstlichem Licht beleuchten? Womit denn sonst? Beanstandet hat die Ausklammerung von UV aus Licht kein geringerer als Matthew Luckiesh. Nicht jetzt, sondern 1925. Und er war weder unbekannt, noch einflusslos. (kompletter Artikel dazu hier) […]

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