Introduction

Sunlight contains large amounts     of UV in various wavelengths. Each wavelength is responsible   for various things, such as tanning response in humans, activate synthesis of Vitamin D, and absorption of calcium and other minerals. In ancient times, the Chinese, Mayas, Incas and Egyptians already worshipped the reviving powers of the sun. Real sun cults were evolving. Greeks and Romans were treating diseases with sunlight.Sun therapy was very popular in Europe at the turn of the century, and until the late 1930's. It was known as heliotherapy, named after the Greek God of the sun - Helios. By mid 1930's, sunbathing and UV therapy was most effective treatments for many infectious diseases such as: lupus, eczema, acne, herpes, rheumatoid arthritis, gout, cystics, anemia, colitis, kidney problems, etc. 36 sanatoriums for heliotherapy were built on the French Rivera in just one year.

Then in 1938, penicillin was discovered, and world turned to pharmaceuticals, and drugs became big business. Sun therapy was then regarded as medical quackery.

Only during the past few years, after many germs had become resistant against the medication, this misdevelopment has been slowed down.

Studies and reports summarized here explain why it is so important to use natural sunlight type lighting wherever possible.