I’ve written here several times about the importance of natural sunlight in the balance of producing good health. Whether its for stimulating Vitamin-D production to managing the body’s circadian rhythm, or internal clock, sunlight is key to all of that. Our bodies have evolved over millions of years in harmony with that natural sunlight. The balance of hormones circulating in our blood stream is regulated by the rising and setting sun, until one day in 1879 when a young man in New Jersey put an end to all of that. Thomas Edison’s invention of the electric light bulb finally enabled humans to free our circadian cycles from the rotation of the planet and allow us access to the 24/7 lifestyle that we value so deeply.
Sleep disorders are now so common in our electric world that we take drugs to fall asleep and another drug in the morning to wake up. Other more prolonged conditions are classified as related to the seasonal changes in the length of the day. We call it Seasonal Affective Disorder (SAD). So the solution for SAD is to let in the light – no not natural light, but artificial light designed to mimic natural light, or “full spectrum light“.
The term full spectrum light was first used in the 1960’s by a photo-biologist named Dr. John Ott. His idea was to identify a lighting source that would approximate the lighting conditions of daylight. You see natural sunlight contains all of the colors of the visible spectrum – the rainbow, while artificial light, depending on the type of bulb used is weighted more in certain colors and less in others.
In general, the color of light can be described in temperature based on the premise that if a “black body” object were heated to a specific temperature, it would emit the color associated with that temperature. Here is a chart of generalized color temperatures.
|1,700 K||Match flame|
|1,850 K||Candle flame|
|2,700–3,300 K||Incandescent light bulb|
|3,350 K||Studio “CP” light|
|3,400 K||Studio lamps, photofloods, etc.|
|4,100 K||Moonlight, xenon arc lamp|
|5,000 K||Horizon daylight|
|5,500–6,000 K||Typical daylight, electronic flash|
|6,500 K||Daylight, overcast|
|9,300 K||CRT screen|
|Note: These temperatures are merely characteristic;
considerable variation may be present.
The first thing you’ll notice is that the color temperature of daylight can range from about 5,000 K on up to 6,500 K. And if you’ve ever spent any time outside, you’ll know that morning light is different than noon light, which is different from late afternoon light. In fact daylight doesn’t come just from one source. Wait a minute you might say, daylight comes from the sun. Yes, but some of that light is also scattered in the atmosphere which produces that blue light that fills in the shadows.
So what does it really mean to make an artificial light that is “full spectrum”? Well as it turns out, “full spectrum” light is not quite a technical term, but rather a marketing term. And different marketing departments at different companies have different definitions of what is “full spectrum”. Here’s a nice graph comparing two artificial lights (one fluorescent and one incandescent) to natural daylight.
Notice how neither artificial lights come close to the blue line of natural daylight.
Yet, there is a perception in the general public that “full spectrum” lights, that cost several times the price of standard lights, have significant benefits including improved health. According the the Lighting Research Center, the general public believes that some of those health benefits include: reducing the impact of SAD, improving mood, improved awareness, improved vitamin-D production and reduced dental decay.
The fact is that full spectrum artificial light sources have no effect on improved health in increased vitamin-D production or on dental decay. Research does show an impact on SAD, but only at lighting levels above 10,000 lux into the eye. Other researchers contend that any light source at this intensity will have a positive effect. Yet, full spectrum light may have a psychological effect on mood and awareness because of the association with natural light color, there is no biophysical connection to the mood change and the light.
The bottom line here is that we are creatures that are in tune with the natural cycles of the sun. Time your activities accordingly. Do more during the daylight, and minimize your dependence on artificial electric light of any kind. Does that mean that you should stumble around in the dark? No. What it does mean is that your health is tied to the sunlight. Trying to compensate for inadequate sun exposure with artificial lights of any color temperature is a myth. If you want better health, shut of the lights and get to sleep. That alone will do wonders to improve your health.
Paul Kulpinski, LMT