Can Light Therapy Help People With Insomnia?

Exposure to light can help some people with certain kinds of insomnia. However, the research is mixed. Let us – ahem – shine a light on it.¹

What is bright light therapy?

Bright light therapy, or just light therapy, can help some people change when they sleep. It can be useful for people who have an irregular sleep-wake cycle. This cycle is also called the circadian rhythm.^1-3

Light therapy can be useful for people who have trouble falling asleep or those who wake up earlier than they want to. However, it may be less useful for people who have trouble staying asleep.²

Light therapy works by resetting the sleep-wake cycle. It does this by exposing your eyes to sunlight or a specially designed bright light at specific times of the day. People most often use the light for 30 to 90 minutes at a time. Light therapy can be used to help you fall asleep earlier or to help you wake up later.^2,4

If you have trouble falling asleep, you may want to use light therapy just after waking up. If you find yourself waking up too early, you may need your light therapy before bedtime.⁴

But first, a warning: Never stare directly at the light. This can injure your eyes.⁴

Getting started with light therapy

Light therapy itself is surprisingly low-tech. This might be part of why it is not often prescribed.⁵

A sleep therapist can help you figure out the best time of day to use light therapy and for how long. Both of these decisions will depend on your sleep situation. Before helping you make these decisions, your sleep therapist may ask you to keep a journal or diary of your sleeping habits. The information you record in your sleep journal will help your sleep therapist understand your sleeping problems and recommend the right therapy.^2,4

You may have questions for your sleep therapist, such as:

• Can I use sunlight?
• What kind of artificial light (or light device) should I use?
• How do I know if the light is bright enough?
• How far should I sit from the light?
• How long should I use the light?
• Is it okay to use light therapy and continue to take my medicines?

How to use light therapy

Different light sources can be used for light therapy. If there is bright sunlight outdoors, that works. Special light boxes that emit light of 1,000 lux (brighter than normal indoor light) and low-intensity light visors can also work. Recent research shows that bluer light is the most effective at changing sleep-wake cycles.⁴

You can use light therapy while doing other activities. If you set the light at your side, you can also:⁴

• Read, knit, or do art
• Watch TV or work on a computer
• Listen to music
• Eat a meal

What is key is exposing yourself to the light source at the same time of day and for the amount of time your sleep therapist recommends.⁴

What does the research say?

Research shows that bright light therapy can change your circadian rhythm. But whether light therapy can help specific conditions like insomnia and depression is not as clear.^1,4

One study reviewed 21 experiments that looked at the effect of light therapy on older adults who had trouble with their sleep or circadian rhythms. It found that most studies showed an effect, but the effect was small. One problem with the study was that many of the experiments it reviewed had a small number of participants. This means the results might not apply to as many people.⁵

A second, newer study used much stricter ways to measure the effect of light therapy on insomnia. This second study also looked at a group of experiments. It found that light therapy was effective for general sleep problems and for insomnia. However, light therapy was not as good for helping people with circadian rhythm disorders. This second study also found that, though light therapy helped people’s sleep problems, the effect was small to medium.¹

Talk to your sleep therapist or doctor if you want to try light therapy.