Very few of us get more than a few snatches of outdoor light (unimpeded by windows and glasses) in the winter months. Here are some salient facts about natural light and why we need it:
1. Forty percent of the population is considered deficient in Vitamin D. Our bodies (most importantly our eyes), need fifteen to twenty minutes of exposure to the full-spectrum sunlight without sunscreens or UV blocking glasses every day in order for the skin to manufacture vitamin D!
2. Most sunscreens only protect against UVB, and overuse of UVB sunscreen can interfere with vitamin D manufacture. Glasses and windows also interfere with absorbing full-spectrum sunlight.
3. The light brightness measurement is called a lux. For therapeutic reasons you need to be exposed to light that is at least as bright as dawn or twilight, of 2,500–10,000 lux, even on cloudy days. Regular incandescent light bulbs don't even get close, producing 500-1,000 lux on the work surface!
4. When natural light is absorbed by the retina of the eye, electrical impulses are carried along the optic nerve to the brain and the hypothalamus, pineal gland, and pituitary gland, where it is used by the body to activate neurotransmitters that turn on many hormonal systems, including the metabolism, reproductive functions, and the internal biological clock called the Circadian Rhythm.
5. The Circadian Rhythm of the body is activated by light that is significantly brighter and more complex in spectrum than that which is needed for visual work. NASA installs full-spectrum lighting in space craft for this reason.
6. Light exposure raises seratonin, which keeps you awake and alert.
Melatonin rises in the dark, which makes you sleepy. It is suppressed by daylight. If you don't get enough light of sufficient intensity (lux) you produce too much melatonin, which makes you groggy. (If you are tired during the day, you might go out and get some sun!)
Our natural body rhythms are synchronized by the changing light of the sun at dawn and dusk, and we need 20 minutes of natural light every single day to keep our natural rhythms in working order. So what can you do?
1. Bathe your eyes in natural outdoor light without any glasses for up to 20 minutes every day. Soak it up in a walk, on a deck, in a lawn chair, at the beach. Through your eyes, light goes directly to the hypothalamus, and from there to every cell in your body—and it helps your skin manufacture Vitamin D, an essential nutrient.
2. Take your lunch break outdoors whenever you can. You don't need to be in the direct sun. A porch is fine!
3. Take the opportunity to read the daily newspaper in the sun; look at your mail there, too.
4. In the winter, walk somewhere that isn't icy, so that you stay warm.
If you are disabled, infirm, or unable to get outside for whatever reason, including living in a city, sit by an open window for 20 minutes or so every day, if it isn't too cold.
For more info visit: http://www.care2.com/greenliving/
Saturday, February 2, 2008
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