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Lux, Lumens and what is a Kelvin?

Hello, Welcome and Welcome back! Have you ever considered that bunny trails lead to rabbit holes, especially when you think you are on to something that peaks your curiosity and it may lead to some really good golden nugget of information? This is what happened last week when it was time to turn the page on light therapy application. And, if you are one that wants just enough information to get this thing started, so you can get on with your day (this is me most of the time; I want the shortest path with least resistance), this blog post may be irrelevant. But, if you want a few words to explain how light in itself works, you may find this helpful. Not only do I appreciate a little science into light and how it measured, I will use this when working with my clients to better assist them in getting the right lighting for specific needs/areas in their master bedrooms.


So, here it is. We already know that in order to receive the best amount of light each morning using Light Therapy, our book (Winter Blues) recommends 10,000 lux of light. To understand what this means I offer the following from my own research and the help of the book and an article by "Lumen Now", found online.


Lux - is a measurement of intensity of light; it gives the illuminance on certain surfaces such as a desk, or light coming off the sky at sunrise, or on a cloudy day, or light just before the sun crests the horizon;

Lumen - is the amount of light emitted by a light source; it's the brightness of light; for example: 1 lumen = light of 1 candle; more lumens = brighter light

Kelvin - is the measurement to describe color temperature of light; yellow (warm), white (cold, direct, intense) or blue (TV screens, cellphones, computer monitors)



Putting those three together for light therapy purposes we can know that 10,000 lux of light (intensity or illuminance) is related to the lumens (amount or brightness) that is related to the Kelvin (color of the light).


Some quick findings (maybe even useful for Trivial Pursuit):

Average room at night = 300-500 lux (equal to about a 40 watt bulb)

Office light = 500-700 lux (most likely Kelvin color blue, especially computer screens)

Sunlight off a summer sky = 100,000 lux (that's alot of light!)


Do remember that natural sunlight exposure is healthy and that 10-20 minutes each day will stimulate enough Vitamin D and serotonin production to be beneficial. With SAD, it takes a decision, not negotiation, with oneself to get out and take a walk. It has to be a choice, regardless of how you "feel". Feelings during your seasonality are at the forefront of your symptoms and overriding how you feel is how you take care of yourself to maintain your physical, emotional and psychological well-being.


This has been one of my favorite bunny trail blog posts. Next week should be directed to offering alternative ways to treat your SAD symptoms if Light Therapy isn't for you. Have a nice week....Jeanine








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