How to Use an SAD Lamp Properly

SAD Lamp Instructions 

Summary: Correct Lamp, 30 min. daily, 2’ away max, straight ahead

1. Most people who use these lamps use them incorrectly and they are then ineffective. So please follow to the letter!
2. Lamp: Your lamp must have a total light output of “10,000 Lux”. 5,000 Lux lights require twice the amount of time for the same effect.
3. Bulbs: Its bulb(s) must put out “natural spectrum” or “full spectrum” light (which mimics the spectrum of the sun). Other kinds of bulbs produce light that will be ineffective.
4. You can purchase the ideal lamp—the one used in many research studies—from Amazon. It is called the “Nature Bright Sun Touch” lamp and it sells for ca. $50-$65 (the price fluctuates). It is one of the best yet one of least expensive SAD lamps. Fancier and more costly lamps are unnecessary and often less effective.
5. Time: You should use the lamp correctly, as described below, a total of 30 minutes every day.
6. When? Start using the lamp daily September 21 and stop March 21. Sept 21 is halfway to the darkest day of the year and March 21 halfway to the lightest. This means you will be using it for entire “dark” half of the year. This fits the most common form of SAD. Your doctor may suggest a different schedule if you have one of the less common variants.

1. Why? With respect to mood, the brain responds to seasonal changes in sunlight in three ways: (a) Total amount of sunlight absorbed by the eyes and the skin (b) Proportion of each color (wavelength) absorbed and (c) The length of daylight time. At the height of summer (June 21 with respect to light, not temperature!), the distribution of colors is “sunniest”, the intensity of sunlight is at its greatest and the time between the beginning of light (dawn) and the end of light (dusk) is at its longest. A good SAD lamp optimizes the artificial equivalent of (b) by putting out a spectrum of light that most closely matches the sun’s on June 21. Your use of the lamp must optimize the equivalent (a) the amount of light you absorb and perhaps also an artificial version of (c), the length of daylight. 85% of a lamp’s effect comes from optimizing the first and is easily controllable by you. The remaining 15% comes from (c) which is more difficult but fortunately less important.
2. Optimizing the total light absorbed = Intensity X Total Time. If the light is used properly,  then 30 minutes will maximize its benefit. Here is what to do:
   1. Place the lamp no more than two feet away.
   2. The lamp should face you directly, and not from an angle.
   3. The light should shine directly onto your face.
   4. Do not look at the light but cast your eyes down, like reading something, for example, which you can do during.
3. Common mistakes to avoid:
   1. Light intensity falls off not proportional to its distance but to the square of its distance. If you double the distance you must quadruple the time. At two feet directly ahead of you 30 minutes is enough. At four feet you’ll need two hours.
   2. Light intensity falls off as the cosine of its incident angle. If you place lamp 60 degrees off straight ahead, you will get 50% of its intensity. At that angle and two feet away you would need an hour.
   3. If you place the lamp conveniently four feet away at a 60 degree angle you’ll need to use it for four hours to get the effect. People who buy 5,000 lux lamps and place it that way would need eight hours. There aren’t enough hours in the day to get anything out of the kind you hang on your wall.
4.  Optimizing the artificial length-of-day. As noted, about 15% of the effect of sunlight comes from the length of time from dawn to dusk. This is shortest December 21 and longest June 21. You can trick the brain into gaining this extra 15 percent effect by using the lamp to create an early artificial dawn and a late artificial dusk. Do this by splitting the 30 minute total time into a 15 minute morning segment and a 15 minute evening segment. But this will only work if you can make the morning segment just before it is fully light and the evening segment just before it is fully dark. Most people cannot fit this into their schedule, especially after daylight savings time which is when it would be the most needed. But don’t be too concerned: If you take good care to do 1. through 9. you will do well.
5. SAD and related mood variability. SAD is one of a closely related family of mood conditions without sharp boundaries between any of them. These include all the various degrees of “bipolarity”, seamlessly, from that typical of most people to extreme forms of manic-depression or “bipolar disorder”. The more severe one’s mood variability, the more sensitive it tends to be any biological cycle or disruption. Major examples include seasonal variability, premenstrual mood changes, nocturnal anxiety and sleep-cycle disruption post-partum depression and severe mood changes accompanying jet-lag.  The closer one’s condition falls in the bipolar direction the more sensitive it is likely to be to the use of SAD lamps. For some people, 30 minutes is too long and may actually trigger a hypomanic state and the time should be shortened to the point that this does not happen. No one should use the lamp immediately before sleep as it is likely to make it hard to fall asleep.