Dark therapy is the process of greatly reducing exposure to any light during the hours before sleep. This is done to prevent the breakdown of Melatonin by blue light, which is an important hormone involved in regulating the bodily circadian rhythm.
Dark therapy has been used successfully for the treatment of mania in bipolar depression, chronic fatigue syndrome, and for migraines and headaches.
The upregulation of melatonin associated with dark therapy is associated with a variety of improvements as well. This includes decreased risk of headaches, cancer, and obesity. Some of the anti-obesity effects may be mediated by melatonin's effects on thyroid function.
A novel approach of simulating total darkness is blocking out light in the blue wavelengths, which are responsible for the breakdown of the hormone melatonin. Amber colored glasses have been used to stimulate dark therapy with efficacy.