Have you ever wondered if it is worthwhile to change the light bulbs in your house to bulbs that have all the wavelengths of visible light, so called full spectrum lights? Wouldn’t it be nice to have sunlight inside your house? (Be warned, full spectrum lights do not replicate sunlight as they have no ultraviolet due to federal law.)
Last century, several researchers studied the effects of both true full spectrum lighting (visible light wavelengths plus UV light) and full spectrum (visible light without UV light) on the physical and intellectual development of fourth graders.
In 1995, one of those researchers, Dr Warren Hathaway in Canada, conducted a fascinating experiment on children, using both visible and UV wavelengths of light. He was not the first to do such experiment (the Russians were), and he cites several earlier Russian studies.
Dr Hathaway selected 327 students from five different schools to participate in the experiment. The students averaged 12 years in age; the study lasted for one year. He placed students in one of four groups. Each group had different overhead lighting during the school day.
- The first group of students had high pressure sodium vapor lamps; these are older lights, now such lights are sometimes used for outdoor lighting.
- A second group of students had “full spectrum” florescent lamps called Vita-Lites; these light reproduce the visible spectrum of sunlight but have no UVB or UVA in them. Many companies make them today.
- The third group of students had Vita-Lites plus UVB and UVA light.
- The fourth group of students had cool-white florescent lamps, lights similar to those in use today, they have neither full spectrum visible light nor any UV light.
He found that children in group 3 (Vita Lites plus UV) had significantly fewer cavities than the other three groups. In fact, when the children who had sealants applied to their teeth were removed from the analysis, the UV group had one fifth as many cavities as the non UV groups! Furthermore, the UV group had significantly better school attendance than the non UV group. And, the highest gains in height and weight were made in the UV group.
Then the findings got even more interesting. Hathaway measured achievement test scores in all the groups before and after the one year study. As expected, all groups showed gains in academic achievement over the year, but the best gains were in the Vita-Lite groups, with or without UV light. That is, the students exposed to lights that replicated visible sunlight, with or without UV added, had the greatest gains in academic achievement.
“One might conclude from these findings that natural light is important to the development and well-being of people, and to imprison people in spaces lit only with artificial lights designed solely for efficiency amounts to a clear case of daylight robbery.”
To return to the question of whether or not you should you use full-spectrum light bulbs in your house, and they are widely available, I recommend it. Anything that brings us closer to natural sunlight, and full spectrum bulbs should replicate the visible wavelengths of natural sunlight (sans the UV), may make our lives healthier. Note that full-spectrum lights are often lacking UV light, except for reptile lights, which have both visible wavelengths and UV.
“Sunlight robbery” or “sunlight deprivation” is almost universal in modern society, and it involves more than just vitamin D. That is why we recommend sunbathing during warmer weather and the safe use of low pressure UV sun beds (which roughly replicate sunlight at the equator at 5,000 feet of altitude) during the darker weeks of the year.