Sleep Education

American Academy of Sleep Medicine 

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Bright Light Therapy - Disorders Treated

Bright light therapy is used for people who suffer from circadian rhythm disorders. The time of day when the light is used will depend upon the disorder it is meant to correct. These disorders include the following:

Delayed sleep phase disorder

This causes people to fall asleep much later at night than is normal. As a result, they also wake up later in the morning. This sleep pattern can interfere with their schedule of activities for the day. To correct delayed sleep phase, light treatment takes place during the early morning hours.

Advanced sleep phase disorder

This causes people to fall asleep much earlier at night than is normal. They also wake up earlier in the morning. To correct it, light treatment takes place early at night.

Free-running or Non-24-hour sleep-wake rhythm

People with this disorder fall asleep at a different time each day. For example, you may fall asleep at 10 p.m. one day, Midnight the next day, 2 a.m. the next, etc. This most often occurs in people who are blind. Light therapy may help blind people, even if they can't perceive visible light. Studies show that light treatment may be useful in the early morning hours.

Jet Lag

Jet lag causes people to have problems with sleep when they have crossed many time zones on a flight. Light therapy in the morning may help when traveling east. For travel to the west, bright light in the evening may help reduce jet lag.

Shift Work

This sleep disorder occurs due to a work schedule, such as night shift, that takes place during the time when most people are sleeping. This schedule requires you to work when your body wants to sleep. Then you have to try to sleep when your body expects to be awake. Correcting it can be a hard problem to solve. Changing work schedules, days off, and social activities can alter your exposure to light from day to day. Frequent changes in your sleep times make it hard to re-set your internal clock. In general, using light treatment in the evening should help someone who regularly works nights. In this case, you would also want to avoid daylight when you come off work and go to bed. Dark sunglasses or special goggles can help.

Seasonal affective disorder (SAD)

SAD is a mood disorder that can cause people to feel sad and lack energy during the dark months of winter. A similar and milder version is often called the “Winter Blues.” In severe forms, sadness may be caused by depression. Light therapy is thought to be useful as one of the treatments for seasonal mood disorders and depression. Depression is also treated with medications. You should consult your doctor if you are having serious problems with sadness.

Possible Side Effects

Light therapy has a good record of safety. It does not seem to produce any major side effects. Light therapy should always be used within the proper limits for intensity and time. Minor side effects may include the following:

  • Eye irritation and dryness
  • Headache
  • Nausea
  • Dryness of skin

To reduce these side effects, begin the light therapy very slowly. Give your body time to get used to it. The use of a humidifier can also help with irritations caused by dryness. Talk to your doctor or a sleep specialist before beginning use.