(phototherapy) 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
Serotonin acts as a neurotransmitter, a type of chemical that helps relay signals from one area of the brain to another. Although serotonin is manufactured in the brain, where it performs its primary functions, some 90% of our serotonin supply is found in the digestive tract and in blood platelets.
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?
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:
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
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.
In this article
This information is produced and provided by the National
Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National
Institute via the Internet web site at http://
.gov or call 1-800-4-CANCER.
WebMD Medical Reference from Healthwise
June 11, 2013
This information is not intended to replace the advice of a doctor.
Healthwise disclaims any liability for the decisions you make based on this