What is light therapy?
Light therapy is exposure to light that is brighter than indoor light but not as bright as direct sunlight. Do not use ultraviolet light, full-spectrum light, heat lamps, or tanning lamps for light therapy.
Light therapy may help with depression, jet lag, and sleep disorders. It may help reset your "biological clock" (circadian rhythms), which controls sleeping and waking.
What is light therapy used for?
People use light therapy to treat seasonal affective disorder (SAD), which is depression related to shorter days and reduced sunlight exposure during the fall and winter months. Most people with SAD feel better after they use light therapy. This may be because light therapy replaces the lost sunlight exposure and resets the body's internal clock.
When should light therapy be used?
Light therapy may be most effective when you use it first thing in the morning when you wake up. You and your doctor or therapist can determine when light therapy works best for you. Response to this therapy usually occurs in 2 to 4 days, but it may take up to 3 weeks of light therapy before symptoms of SAD (such as depression) are relieved.
It's not clear how well light therapy works at other times of the day. But some people with SAD (perhaps those who wake up early in the morning) may find it helpful to use light therapy for 1 to 2 hours in the evening, stopping at least 1 hour before bedtime.
Is light therapy safe?
Light therapy generally is safe, and you may use it together with other treatments. If symptoms of depression do not improve, or if they become worse, it is important to follow up with your doctor or therapist.
The most common side effects of light therapy include:
- Eye strain or visual disturbances.
- Agitation or feeling "wired."
You can relieve these side effects by decreasing the amount of time you spend under the light.
People who have sensitive eyes or skin should not use light therapy without first consulting a doctor.
Always tell your doctor if you are using an alternative therapy or if you are thinking about combining an alternative therapy with your conventional medical treatment. It may not be safe to forgo your conventional medical treatment and rely only on an alternative therapy.
Other Works Consulted
- Bongiorno PB, Murray MT (2013). Affective disorders. In JE Pizzorno, MT Murray, eds., Textbook of Natural Medicine, 4th ed., pp. 1162–1180. St. Louis: Mosby.
- Terman M, Terman JS (2006). Controlled trial of naturalistic dawn simulation and negative air ionization for seasonal affective disorder. American Journal of Psychiatry, 163(12): 2126–2163.
Current as of: September 23, 2020
Author: Healthwise Staff
Medical Review: Adam Husney, MD - Family Medicine
Brian O'Brien, MD, FRCPC - Internal Medicine
Kathleen Romito, MD - Family Medicine