Blue light therapy for sleep disorders: Insomnia, DSPS, and ASPS


New technology and research on circadian rhythm dysfunction has opened up opportunities to apply therapy using blue spectrum light to help reset the body clock.


What is blue spectrum light and why does it matter to sleep?

In this blog, we've previously discussed circadian rhythmsand how they rely on light cues to help us regulate our sleep-wake cycles.

For those who suffer from circadian rhythm disorders, the use of light therapy—especially with blue spectrum light—has become a nonpharmacological way to help people "reset" rhythms that have shifted from normal schedules.

These system shifts lead to problems with getting enough sleep.

Why is blue spectrum light singled out?

While most visible wavelengths on the light spectrum can reset the body clock, the most efficient way to alter circadian rhythms is by using blue light. 

Research suggests that circadian rhythm misalignments are a growing problem. 

Dieter Kunz, director of the Sleep Research and Clinical Chronobiology Research Group at Charité–Universitätsmedizin Berlin, said that “a growing body of evidence suggests that a desynchronization of circadian rhythms may play a role in various tumoral diseases, diabetes, obesity, and depression.” 

It's also responsible for our national problem with sleep debt and sleep deprivation.

While white light has long been used to help treat mood disorders, blue light has emerged as a two-for-one application, for treating both circadian rhythm disorders and mood disorders—which sometimes go hand in hand. 

Wait... Isn't blue spectrum light bad for sleeping? 

Yes! If you have normal healthy sleep, you can actually do yourself a disservice by exposing yourself to blue light at inappropriate times.

The most common sleep hygiene problem we have in the US is using devices with backlit screens right before bedtime. This includes smartphones, tablets, handheld games, laptops, even close-range TVs.

What's worse, we're taking gadgets to bed with us, and using them in the dark. This is problematic: blue light immediately stops the brain's pineal gland from releasing a natural hormone, melatonin, which is critical for the onset of sleep.

This naturally occurring melatonin should be released approximately 2 hours prior to your natural bedtime. Without it, the body cannot launch into sleep.


The large numbers of insomniacs posting comments online at 2 am is evidence enough: we need to adopt best practices at bedtime to remove these hazards. Using blue-light filters on our devices and wearing blue-blocking glasses with UV-protective, orange-shaded lenses are two solutions, if putting gadgets away is impossible.

Three circadian rhythm sleep disorders which benefit from blue light therapy

Other sleep disorders may also warrant the occasional use of phototherapy: jet lag, free-running or Non-24-hour sleep-wake rhythm, shift work disorder, and SAD. 

Blue light sources


The sun is still the brightest light we can expose ourselves to.

Even on a cloudy day, the brightness from natural light still eclipses anything you can expect from ordinary home lighting.

Yes, this means that even on a foggy or overcast morning in Seattle, you are still getting a lot more bright light outside than if you were to duck into a coffeehouse for a latté.

A common recommendation for people with all kinds of sleep disorders is to go outside for 20 minutes every morning as a way to enhance or reset rhythms. 


Other considerations

Using blue light therapy involves answering two basic questions: "How much light intensity?" and "How much light exposure?" Here are some observations.

About lux

Lux is defined as the measure of how much light your eyes receive and perceive. Higher lux levels have become the norm in light box treatments. Between 8,000 and 12,000 lux is a pretty common concentration to expect from most therapy lights.

However, keep in mind that your distance from applications of light exposure are key to success. Staying within the range of 18 to 24 inches is recommended.

On the other hand, if you sit 4 feet away from your light, the intensity of your light therapy can be diminished by as much as 75 percent. 

It's worth noting here that you don't have to look directly at the light for it to work; you just need to have your eyes facing the light. 

About duration

Recent research in a study published in SLEEP shows that it's not the intensity of the light that matters as much as the amount of time exposed to it. Phase shifting does not seem to increase with the increase of lux units, but spending more time in front of the light does.

However, researchers still can't agree on the perfect lux level or duration for light therapy (though 10,000 lux is the most common intensity cited). Instead, they mostly encourage users to try larger boxes so that it is easier for them to stay within the therapy's visual range.

Does light therapy work?

According to the Circadian Sleep Disorders Network, sometimes. Users may find using light therapy allows them to return to the 9-to-5 schedule. Others have partial success, shifting up to 2 hours in the direction they need, but not more than that. Others find that they can achieve a normal sleep-wake cycle, but it's not all it's cracked up to be. 

A note about side effects

While light therapy is considered safe, it does not come without its adverse reactions. Some users report trouble with their eyes, hyperactive behavior, stomach upset, headaches or migraine, and dry skin after using light therapy.   

Using light therapy should take place under the supervision of a doctor; "self treating" could actually worsen your sleep phase problems. If you have other medical issues, you might aggravate them as well. Someone with bipolar depression, for instance, cannot use light therapy without risking the trigger of manic episodes.

Just because light therapy is not a drug does not mean it's a safe choice for everyone. It's better to be safe than sorry. A knowledgeable sleep specialist should be included in your treatment protocol to ensure you get the most appropriate light therapy plan for your specific concerns. 

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