Light Therapy, Bring Florida to Your Home this Winter
As seasonal migrants spend the winter months in sunny Florida, many local residents are visiting their family doctor’s office for the winter blues, also called Seasonal Affective Disorder (SAD).
SAD is a condition caused by a possible shift in our internal biological clock, the circadian rhythm, due to diminished daylight.
Symptoms include depression, fatigue, lack of motivation, inability to concentrate, increased sleep, craving for sweets, weight gain, irritability, anxiety, and social contact avoidance. If you have similar symptoms, and especially if you have also had them during previous winters, you may have SAD.
SAD is rather common, affecting up to 10 percent of the population in the northern United States. Light therapy is the most studied treatment for SAD; in fact, it is at least as effective as antidepressants and works faster, with fewer side effects. Light therapy is done by simply sitting close to a light source with your eyes open.
There are many affordable light boxes on the market. Since the FDA does not regulate light boxes and they may not be covered by insurance, you should seek a device which clearly states it is designed for SAD. Look for details about intensity, safety, cost, and style. Normally, UV light should be filtered out. Keep in mind that when it comes to size, bigger light boxes may not be more effective.
Efficacy depends on treatment duration, timing, and intensity. Intensity is measured in “lux;” for example, normal office lighting is around 400 lux and full daylight with no direct sun is at or over 10,000 lux. Treatment intensity is from 2,500 to 10,000 lux and duration can be 15 minutes to two hours. At the beginning, it would be a good idea to start low and slow, and keep a longer distance from the light source. In addition, it is recommended that you avoid looking directly into the light box during treatment.
Light therapy could have some side effects, but they are few and typically reversible. Symptoms may include eye strain, headache, nausea, agitation, or trouble falling asleep (if done late in the day). Bipolar patients can sometimes develop hypomania or mania. People with diabetes and pre-existing eye conditions should have an eye exam before treatment. Some medications can cause photosensitivity, too. All treatment plans should be monitored by a physician.
In addition to light treatment, natural light exposure from outdoor activities is also helpful. Because snow reflection is part of natural light, you may also receive light therapy as you shovel snow or go for a winter hike. With light therapy, you can be content right where you are and will have no need to join the seasonal Florida migrants to find happiness this winter.
(Dr. Dongsheng Jiang is an Assistant Professor of Family and Community Medicine with Penn State College of Medicine’s University Park Regional Campus. The author thanks Lauren Lubus and Dr. Michael Flanagan for editing the article.)