Light Therapy for Sleep Disorders: Insomnia, DSPS and ASPS

Key Takeaways

Light Therapy and Circadian Rhythm: Light therapy, also known as phototherapy, is a treatment that involves exposure to artificial light to regulate the body’s circadian rhythm. By mimicking natural sunlight, light therapy can improve the timing and quality of sleep for those struggling with delayed sleep phase syndrome (DSPS) and advanced sleep phase syndrome (ASPS).
Benefits and Mechanism of Light Therapy: Light therapy is effective because it affects the body’s production of melatonin. Exposure to bright light, especially in the morning, helps suppress melatonin production, signaling to the body that it’s time to wake up. Conversely, dimming the lights before bedtime and avoiding electronic devices can promote melatonin production and signal the body that it’s time to sleep.
Recommendations for Light Therapy: Light therapy should be administered early in the morning, ideally within an hour of waking up, to reset the circadian rhythm effectively. The therapy session should last between 20 to 40 minutes, and patients should keep their eyes open to absorb the light. Light boxes producing around 10,000 lux of light are recommended, and patients can engage in other activities during the session.

Humans are diurnal by nature, meaning that we are typically awake during the daytime and asleep at night. But this schedule isn’t just an old habit we picked up across the generations; it’s rooted in our biology. Humans are built to respond to darkness and light with sleep and wakefulness, respectively.

It makes sense then that regulating light, either by blocking it or adding it to our day, can improve sleep. When you have insomnia or circadian rhythm disorders like delayed sleep phase syndrome or advanced sleep phase syndrome, light therapy may be an option to help improve your sleep schedule.

In this article, we’ve dug into the benefits of light therapy for sleep disorders and how this simple yet innovative treatment can help to improve the timing and quality of our sleep.

What is Light Therapy?

Light therapy helps to treat certain conditions with sessions of intentional exposure to artificial light. During treatment, the patient sits in front of a bright light designed to emulate natural sunlight. Light therapy goes by many names: light exposure therapy, circadian light therapy, bright light therapy, and phototherapy.

Light therapy was originally developed to treat seasonal affective disorder Verified Source ScienceDirect One of the largest hubs for research studies and has published over 12 million different trusted resources. View source (SAD), a periodic depression that sets in during the fall and winter Verified Source ScienceDirect One of the largest hubs for research studies and has published over 12 million different trusted resources. View source when days grow shorter and access to daylight becomes limited. However, the use of light therapy has expanded over the years. Light therapy has been shown to benefit people with insomnia, delayed sleep phase syndrome, advanced sleep phase syndrome, attention deficit hyperactivity disorder, and other psychiatric conditions.

How Light Therapy Works

The concept of light therapy Verified Source Harvard Health Blog run by Harvard Medical School offering in-depth guides to better health and articles on medical breakthroughs. View source is simple: patients are exposed to a specially designed light source every day, usually at the same time, for a set duration. During the session, cells in the eyes absorb the bright light and communicate with the biological clock, in an area of the brain called the hypothalamus.

The hypothalamus Verified Source Medline Plus Online resource offered by the National Library of Medicine and part of the National Institutes of Health. View source is the part of the brain that is involved in regulating many of our daily functions, including sleep, mood, hunger, and body temperature. It does so via connections to dedicated neural networks controlling these functions.

Because our bodies are trained to respond to sunlight, light therapy works best when it mimics natural outdoor light. It is common for light therapy patients to use a light box equipped with 10,000 lux. Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source Lux is a measurement of the illumination provided by one lumen or unit of light.

Regularly engaging with this type and intensity of light, at the appropriate time of day helps reset the circadian rhythm, restoring the body’s natural schedule. Usually early morning or after dusk will be most effective for resetting the circadian clock.

The Role of the Circadian Rhythm in Sleep

The circadian rhythm is a daily 24 hour rhythm that is generated by the body’s natural clock, also known as the circadian clock that is located in an area of the brain called the hypothalamus. Sleep is a circadian rhythm that is timed by the circadian clock. Humans naturally follow a 24-hour cycle, keeping in step with the earth’s rotations and the local time.

Circadian rhythm disorders occur when the system gets out of whack, causing a disconnect between the body’s internal clock and the external rhythms of the day. These disorders Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source impact our ability to fall asleep and wake up at the “right” times.

Insomnia

We usually think of insomnia as Verified Source Mayo Clinic Ranked #1 hospital by U.S. News & World Report and one of the most trusted medical institutions in the world. The staff is committed to integrated patient care, education, and research. View source the inability to sleep at night, but it’s more than that. People with insomnia may have trouble falling asleep or staying asleep. They may also struggle to sleep through to their alarm. They often wake early–too early–and can’t get back to sleep.

Everyone has an episode of insomnia every once in a while. However, when you experience three or more instances of insomnia every week for three months or more, it’s classified as an insomnia disorder. Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source

Stress is a significant contributor to insomnia, but other causes include travel, shift work, poor sleep hygiene, or eating too late at night.

Delayed Sleep Phase Syndrome

Delayed sleep phase syndrome, or DSPS, is an offset sleep schedule that starts and ends two or more hours later than what is typical for most people. People with DSPS may struggle to go to bed at a reasonable hour. Often, this means that their sleep becomes shortened, as they may force themselves awake before they’re ready due to school or work obligations.

Many teens naturally follow a schedule that mirrors DSPS, going to bed late and sleeping late into the morning. However, most grow out of this adjusted schedule as they age into adulthood. People with DSPS, however, will struggle past puberty.

Advanced Sleep Phase Syndrome

The opposite of DSPS is advanced sleep phase syndrome, or ASPS, in which the body’s sleep cycle starts and ends two or more hours earlier than usual. People with ASPS struggle to stay awake until a “normal” bedtime, falling asleep early in the evening and waking up early the following day.

As with DSPS, people with ASPS may often experience abbreviated sleep schedules, as they force themselves to stay awake in the evening for professional, social, or family reasons.

Non-24-Hour Sleep-Wake Disorder

While they are considered circadian disorders, ASPS and DSPS still run on a 24-hour schedule. Non-24-hour sleep-wake disorder does not. In this condition, the sleep-wake cycle is considered “free-running,” following its own timeline.

Non-24-hour sleep-wake disorder is generally rare Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source but frequently affects people who are blind, as they lack the sense of light and darkness that seeing people absorb through their eyes.

Other Disorders that Affect the Circadian Rhythm

Traveling and overnight work schedules also tend to throw off our circadian rhythm, resulting in jet lag and shift work disorder, respectively.

Effects of Insomnia and Circadian Rhythm Disorders

Getting enough good, quality sleep can be a challenge for people with chronic insomnia, DSPS, ASPS, and other circadian disorders. When sleep is delayed or cut short, daytime functioning is often affected.

Common symptoms of inadequate sleep include:

Excessive daytime sleepiness and fatigue
Irritability or moodiness
Lack of concentration or focus
Poor memory

People with ASPS should especially be cautious in the late afternoons and evenings, when the pull of sleep may make certain activities like driving especially dangerous.

Over time, persistent sleep deprivation can result in more severe effects, such as an impaired immune system, increased risk of obesity and disease, and a greater risk of mistakes or accidents.

How Light Impacts the Circadian Rhythm

Light plays a vital role in the circadian rhythm, as it suppresses the production of melatonin. When darkness falls after dusk, it signals to our bodies that it’s time to raise melatonin levels.

While most people think of melatonin as an over-the-counter supplement to help them sleep, it is not an herbal remedy; it is a natural hormone produced by our bodies to send us to sleep. When the sun sets, the pineal gland pumps out melatonin, which begins to lull us into sleep.

Early in the morning, the bright light helps us wake up and energizes us for the day, but its effects last into the evening. Exposure to bright light Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source in the morning helps to encourage earlier melatonin production in the evening, because light is a time signal for the clock in the brain.

In other words, the benefits of sunlight for sleep include allowing your internal clock to correctly govern the timing of the various circadian rhythms in the body. Sunlight also boosts vitamin D, produces endorphins, and may offer several other health benefits as well.

It’s clear that light and darkness are both necessary for good sleep. The trick is to manage the light around us throughout the day, ensuring that we’re getting the right balance of light and dark at the correct times. Those bright lights that are helpful early in the day become problematic late at night. Indoor lights and using electronic devices before bedtime can make it hard to sleep.

Dimming the light before bedtime, putting away our devices, and using light therapy can all help to get–and keep–our circadian rhythm on track.

How to Practice Light Therapy

The mechanics of light therapy are simple, and light therapy can be done anywhere, making it incredibly accessible as a treatment. All you need is a bright light source and some time.

Choosing a Light Source

Light therapy boxes come in a variety of forms, from floor lamps to alarm clocks. LED glasses are an ultra-portable option that allow movement during treatment. A prescription is not required, and the Food and Drug Administration does not regulate light boxes. However, a doctor may offer guidance in selecting a suitable device.

The best light boxes for sleep and seasonal affective disorders produce 10,000 lux of light with minimal UV rays.

Some light therapy boxes are specially designed and marketed to address specific issues. For sleep issues, a light box that filters out UV light is key to minimizing the risk of damage; UV is not necessary for treatment. Light boxes made for skin disorders often don’t eliminate these rays as part of treatment and should be avoided.

Practicing Light Therapy

Light therapy is best early in the morning, less than an hour after waking up, and should be completed at the same time every day. This routine is critical to restoring the circadian rhythm.

The light box should be positioned 16-24 inches from the face. If using an alternate light source like LED glasses, it’s essential to follow the instructions provided to ensure safety and effectiveness.

Keep your eyes open during treatment, allowing them to absorb the light. You don’t have to stare directly at the light box (in fact, we don’t recommend it); your presence in the light is all that matters. You don’t have to sit motionless either, you can multitask during your sessions by reading, writing, or even scrolling through your phone.

Each session should last 20 to 40 minutes. Sleep specialists can help determine the optimal time and duration for the therapy, depending on the individual patient’s needs.

Some patients see improvement within days of starting light therapy. Others need a few weeks for the effects to take hold. Keeping a consistent rhythm is key.

Is Light Therapy Safe?

Light therapy is considered safe when used appropriately. However, as with any treatment, there are some potential side effects:

Eyestrain or visual disturbances
Headache or more serious migraines
Agitation or irritability
Hyperactivity, mania, or euphoria
Nausea
Sweating
Skin irritation

Some people may be more sensitive to these side effects than others. Existing conditions like bipolar disorder, preexisting eye problems, and lupus, which makes the skin more sensitive to light, can increase the risk of experiencing side effects. Certain medications and supplements also increase light sensitivity, such as St. John’s Wort and certain antibiotics and anti-inflammatories.

For many patients, the side effects are minor and go away on their own. Easing into therapy with progressively longer sessions can be helpful as well. Following a doctor’s guidance is key to minimizing side effects and using light therapy effectively.

Other Ways to Manage Insomnia, DSPS, and ASPS

While light therapy is a great tool to manage insomnia and circadian rhythm disorders, it may not be right for everyone. It may also only be a part of a comprehensive treatment plan. There are many other ways to support the circadian rhythm and improve the experience of these issues for better sleep. Here are some recommendations for better sleep

Stick to a regular sleep schedule

With insomnia, DSPS, and ASPS, the cycle is the issue. A consistent sleep schedule helps our bodies and minds know when to go to bed and wake up. It’s essential to keep to the schedule throughout the week and on the weekends too.

Manage light in the bedroom

As we’ve discovered, light can aid in your wakefulness or prevent your sleep, so use it wisely. Invest in blackout curtains to keep outside light at bay during the night. Dim overhead lights in the evening to help ease the body and mind into bedtime. Avoid bright lights and put electronics away one to two hours before bed.

Get outside every day

Especially in the morning, when you can enjoy the benefits of early sunlight. Light boxes and light therapy imitate natural sunlight to manage depression and sleep, but getting out in the real thing offers even more benefits, especially if your time outdoors is active.

Get regular exercise

Exercise improves sleep and reduces stress, one of the triggers for insomnia. it helps to regulate the body’s internal clock and promotes a consistent sleep-wake cycle. Second, physical activity increases the production of endorphins, which can reduce stress and anxiety, leading to better sleep quality. Lastly, exercise can tire the body and make it easier to fall asleep fast.

The American Heart Association recommends at least 150 minutes–just two and a half hours–of moderate exercise every week.

Limit caffeine and other stimulants

The chronically sleep-deprived often rely on coffee and other caffeine-charged drinks just to get through the day. However, stimulants like caffeine can prevent good sleep, and other substances throw off the body’s sleep schedules in other ways.

Frequently Asked Questions

How does light therapy affect sleep?

Consistent light therapy, when used as directed by a medical specialist, can help a person fall asleep earlier or wake up later, depending on what their needs are. For example, people with advanced sleep phase disorder tend to feel sleepy early in the evening, well before their desired bedtime. A light box can help them feel awake and alert at night.

Conversely, people with delayed sleep phase disorder find it difficult to fall asleep until late in the evening. These patients may use a light box earlier in the day to stimulate wakefulness.

What disorders does light therapy treat?

Light therapy is often used to alleviate depression rooted in seasonal patterns, a condition known as seasonal affective disorder (SAD). A light box can also be used to ease other types of depression, since natural light is a key part of regulating moods. People with a sleep disorder may also use a light box to help regulate circadian rhythms.

Similarly, people who work a night shift may use a light box to help promote wakefulness or alertness during their shift. It would be most useful for night shift workers to use the light box an hour or so before starting the shift, and as needed during their night shift. For shift workers, using the light box during the day may not be helpful as this is when they will try to sleep.

Certain lamps that emit ultraviolet light can be used to treat skin disorders like psoriasis, although this light therapy is different from light box therapy.

What time of day should light therapy be used?

People often turn on their light box in the early hours of the morning after they wake up. However, it depends on the circadian rhythm disorder being treated, as some patients may need light exposure later in the day to deal with a condition like advanced sleep phase disorder.

Doctors usually have patients perform light therapy sessions that last between 20 minutes to 2 hours. Speaking with their doctor can help patients devise a light therapy treatment schedule that meets their needs.

Does light therapy help with anxiety?

Yes, light therapy can be used to significantly relieve anxiety, Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source along with depression. A 2013 study observed no significant differences between high-intensity and low-intensity treatments, although the study was specifically observing anxiety in patients with focal epilepsy.

Getting more daylight exposure may also help an individual better manage their anxiety symptoms.

What are the side effects of light therapy?

Light therapy can typically be safely used with other treatments, but there is still a potential for side effects. Common side effects are usually mild and can include eyestrain, headaches, hyperactivity, agitation, nausea, sweating, or skin irritation. Decreasing the amount of time spent in light therapy can usually alleviate these symptoms. Medical experts recommend patients with sensitive eyes and skin consult with their doctor before they begin light therapy.

The Bottom Line

When falling asleep and waking up at the right times becomes challenging due to insomnia or other sleep disorders, light therapy can help. Light therapy is a safe, flexible, and effective way to restore the circadian rhythm and improve sleep.

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