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  • Writer's pictureDr. D


...and improve your mood

Sunny day/sunny mood

It’s the time of year for feeling low, foggy thinking and no energy for many people. When someone’s mood is lower just in fall and winter, we say they have “SADs” or Seasonal Affective Disorder.” Bright Light Therapy (BLT) is a natural way to treat this problem.

Hippocrates, thousands of years ago, recognized that exposure to sunlight could help a number of conditions, including depression. In fact, he frequently recommended time in the sun and sunbathing for individuals with low mood. I’ve often joked that I would be the most popular psychiatrist around if I prescribed a visit to the south of France to my patients with SADs. Unfortunately, insurance won’t cover it.

Most of us find that our mood is better at ten above zero and sunny than when it’s sixty and overcast. BLT mimics the effect a sunny day has on us.

No – your tanning bed won’t do the trick.

Individuals who routinely use tanning beds often say that tanning can dramatically improve mood. However, controlled studies don't support that claim. It may be that some people do

notice a benefit from lying in a tanning bed. However, most will not, or only temporarily.

Further, the damage caused by the intense UV light that tanning beds emit, including drying and wrinkling of the skin and skin cancers, outweigh any benefit that might occur.

How Bright Light Therapy works

It’s well known that Vitamin D is increased by the sun shining on our skin. Because of this, it is often suggested that Vitamin D production is the reason that BLT helps our mood. However, this is not the case.

Bright lights used for mood disorders don’t target the skin. They target the retina. This is because bright light shining in the eyes appears to increase the production and release of some of the brain chemicals (neurotransmitters) that control our moods.

Not just any light will do

Workers in interior offices without windows may suffer from a lowered mood year-round. This is because the light usually found in the workplace is different from sunlight and it affects the body differently

Therapeutic light is “broad-spectrum” light. This means that it uses all the light waves in the spectrum; red, yellow, blue, purple, orange and so on but not the dangerous ones. Tanning beds use only the burning (and dangerous) rays.

Typically, a light bulb used for BLT is described as having 10,000 lux or lumens. “Lumens” is a measure of the intensity of the light. Broad spectrum lights of lower intensity can be beneficial, but 10,000 is the best.

How to use bright light therapy

When I prescribe BLT, I tell the person to position the light so that it hits the retina. This doesn’t mean stare at the light. They could watch TV or read or do something else as long as the light strikes the back of the eyes. In other words, they can’t sleep or close their eyes for it to work. It’s best if the light is about 24 – 30 inches from the face.

BLT is best used in the morning for about thirty minutes. Using the 10,000 lumen light later in the day may interfere with sleep. If the intensity is significantly lower it may be possible to use it longer and later in the day, though it may not be as effective.

Thyroid and Vitamin D abnormalities may affect mood

Before assuming that you have a mood problem that will respond to bright light, it’s best to have a few physical things checked out. For example, if your thyroid hormone is low you may

be sluggish, tired and appear moody. Likewise, if your vitamin D level is quite low you may find your mood is lower or that generally you feel less physically well.

Talking to your doctor and having the levels of thyroid hormone and vitamin D determined is better than simply taking supplements on your own. Excessive amounts of thyroid hormone can cause changes in other parts of your body including the heart. Contrary to popular belief, it is also possible to get too much Vitamin D. If this occurs, muscle weakness, nausea, kidney stones as well as

other problems can result.

Not all kinds of mood problems respond to BLT. It’s best to talk to a mental health professional before assuming that what ails you is going to respond to broad spectrum light. This is especially important if you’re having suicidal thoughts.

Migraine and bipolar disorder sufferers beware

Not everyone should use BLT, or should use it only cautiously. If you suffer from migraine you may find that exposure to BLT can trigger headaches. If this happens, a slightly lower intensity light could be tried. Likewise, using it for a shorter period might be beneficial. If you know you’re more susceptible to migraine at a specific time of the month or week, avoiding those times might also help. If the migraines continue, though, this therapy may just not be for you.

People with bipolar disorder are at particular risk of problems, especially mania, when using bright light therapy. Before attempting to use BLT, it is strongly recommended that you talk to your mental health provider.

Summing up

There’s a lot more to talk about with BLT and I will in the future. Today, however, I want to emphasize a few key points.

1. Bright light therapy can be quite effective, but the right kind of light delivered to the correct part of the body, the retina, has to be used.

2. “Tanning” and tanning beds are neither effective nor acceptable for treating mood problems either in the short run or for long term use.

3. It’s always wise to discuss your mood changes with a professional.

4. No type of treatment works for everyone, and bright light therapy is no exception.

Image of sunburst by: aldorado

Image of tanning bed by: husard

Image of vitamin D molecule by: zerbor

Image of thyroid glands/hormone by: Kateryna_Kon


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