How Does Light Therapy Improve Sleep & What are its Side Effects?

Light helping in getting good sleep is a bit of a contradictory statement to put up, but, it does.

Light therapy is a beneficial treatment for certain sleep disorders related to the circadian rhythm.

What Is Light Therapy?

Light therapy is basically a therapy done with bright light that is brighter than the room light but less bright than the direct sunlight.

During the light therapy, the patient needs to sit near a special lightbox for a certain period of time. The light from the box mimics the outdoor light. It is important for regulating the body’s sleeping and waking cycle. The therapy adjusts the circadian rhythm.

Light therapy can be done from the comfort of home. It can be used in various types of sleep disorders such as jet lag, depression, and seasonal affective disorder (SAD).

The light therapy improves sleep quality by affecting certain brain chemicals associated with sleep and mood.

How Does Light Therapy Improve Sleep?

Insomnia can be due to the disruption of the circadian rhythm that is related to the sleep-wake cycle.

If the circadian rhythm is disrupted, there is daytime sleepiness and depression. Light therapy, if used correctly, can reset the circadian rhythm and improve sleep and other symptoms.

Research shows the benefits of light therapy for people with depression.(1) A meta-analysis found light therapy is effective in sleep problems involving circadian rhythm and insomnia(2)

Types Of Sleep Disorders That Can Be Corrected With Light Therapy

Light therapy can be used for correcting circadian rhythm sleep disorder, such as sleep-onset insomnia. In this disorder, a person finds it difficult in falling asleep at a normal time but can sleep well once he falls asleep. It can be due to delayed or advanced circadian rhythm.

In advanced sleep phase disorder, the person tends to fall asleep early i.e. around 6 pm – 9 pm and wakes up around 2 am – 5 am.

In delayed sleep phase disorder, the person stays awake late, often past midnight. He wakes up later in the morning.

Light therapy in the early evening can help reset the internal clock. It can also be used for the following conditions in which disrupted sleep is a symptom.

What Should You Know Before Selecting A Lightbox?

Before purchasing a light box, it is important to consult a doctor about your sleep problem. The doctor would determine whether the sleep problem is due to a circadian rhythm or any other cause.

Lightbox would not cure the sleep disturbance due to a cause other than the disruption of the circadian rhythm.

Make sure you ask the doctor about the safety of lightbox if you have below mentioned symptoms:

  • Eye problem that could get aggravated after using a lightbox
  • Bipolar disorder, as light therapy would trigger mania
  • Lupus, the light would make the skin sensitive
  • Taking medications such as antibiotics or anti-inflammatory
  • Taking supplements like St. John’s wort that would increase light sensitivity
  • Make sure the box you take filters the ultraviolet (UV) light.

According to the doctor’s advice, you need to adjust the light intensity of 2000-10000lux.

Light therapy glasses are also available and are more convenient as they provide freedom of movement. A study found them being more effective than the lightbox(3)

How To Do A Light Therapy For A Sleep Disorder?

Depending on the type of circadian rhythm disruption, light therapy can be done in the morning or early evening hours, before drowsiness sets in.

Keep the lightbox 16-24 inches away from the face. The light should reach the eyes but make sure you do not look directly into the box. You can eat, drink, or use any electronic device during the session.

The main purpose of the therapy is to expose the person to light for a set period of time. The session length is 30 minutes to 2 hours, depending on light intensity and doctor’s recommendation.

The improvement takes a few sessions to show up, therefore, it is important to stick to the therapy session for a few weeks.

Side Effects Of Light Therapy

Light therapy is safe but can lead to minor side effects in some people. The side effects include:

These side effects do not last for long. In case the side effects are severe, stop the therapy and contact a healthcare professional.

Light therapy is a non-invasive treatment for sleep disorders. It helps set the circadian rhythm and improves sleep.

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