How Does SAD Light Therapy Work?
Overview Seasonal affective disorder, or SAD, is a mood disorder that generally strikes during the winter months. People who suffer from SAD may experience symptoms of depression only during the winter months but feel normal during other times of the year. The lack of exposure to outdoor light during the winter season is a contributing factor to SAD, and light therapy may be an effective treatment for people with the disorder. Melatonin and Light Melatonin is a hormone that regulates the body’s circadian rhythms, or internal body clock. Circadian rhythms are tied to the cycles of sleep and other bodily functions. The body’s release of melatonin is controlled by exposure to light. When there is not enough light, the body produces melatonin to induce sleep. During the winter months, when people spend more time indoors and periods of daylight are shorter, the body’s melatonin levels may become imbalanced, leading to symptoms of depression such as extreme fatigue, increased desire to sleep