bright light therapy, circadian rhythm, dementia, hormones, parkinsons, red light therapy, sleep, testosterone - August 27, 2021

Bright Light Therapy From Red Light Panels – Improve Sleep, Hormones, and Mood with high Lux Light!

Parallel to Red Light Therapy and Photobiomodulation, research on the benefits of Bright Light Therapy has skyrocketed over the recent years.

As the name implies, Bright Light Therapy exposes a person and their eyes to bright lights. Sometimes using devices like SAD Lamps, Sunlamps, Mood lamps, Light Boxes, Intra-Ear Lights, or Light Therapy Glasses – these devices deliver bright lights marketed to reset circadian rhythms, reduce jetlag, improve wakefulness, improved mood, provide energy and alertness, and improve sleep.

Those immediate benefits aren't the only use for Bright Light Therapy, it is now being studied for many chronic diseases!

How does Bright Light Therapy work and why is it so important? What are the benefits from it and how do we protect ourselves from bright light deficiency diseases? Are we getting it with our Red Light Therapy Devices?

That is what we will dive into in this blog.

Brightness versus Intensity:

In Red Light Therapy we normally talk about the power or intensity of the light being emitted, usually in terms of Watts or mW/cm^2. With Bright Light Therapy, the important measure is the Lumens or Lux from the light.

Lumens and Lux are a measurement of brightness because they take into account the human eye’s spectral sensitivity to light. Lumens account for the entire amount of brightness emitted by a light, where Lux is the brightness that reaches a given area.

Human eye sensitivity means that certain wavelengths of light appear “brighter” than others, even at the same intensity. It has been well documented by the spectral curve below.

Photopic Luminous Efficacy Brightness Lumens

[8]

For example, Near-Infrared light is invisible to the human eye, so it always is zero lux or lumens – even if it is emitted at a high intensity. The brightest color is Green at 555nm, and we see the graph sloping downward from either side.

We can also find conversion factors and tables on several websites to help us convert Watts to Lumens (and vice-versa). [11] So we see it is a direct relationship which follows the brightness sensitivity curve we display above.

We can also note from this table and the graph above that red light at 630nm is over 4 times as bright as deep red at 660nm. Which is another reason why we like to include 630nm LEDs in most of our panels, to increase the potency of bright light therapy (which we will explore later in this blog).

Deficiency in Bright Lights?

In the modern world we spend an excessive amount of time indoors, in school, in the office, at home. Many people aren’t spending as much time outside in natural sunlight compared to our ancestors.

Sunlight Through Clouds Bright Light therapy

Note the bright blue sky and direct brightness from the sun in this photo.

Direct daylight is up over 100,000 lux! In the shade is still 20,000 lux, and even on a cloudy day is still 1,000-2,000 lux. [9]

Indoor Office Lack of Brightness

Compared to a brightly lit office is only 500 lux, and a typical home may only be 300 lux during the day.

As stated in one study:

“Relative daylight deprivation, however, is relatively common and occurs namely at work places having reduced direct access to daylight such as coal mines, nuclear reactor facilities, library archives, indoor shopping malls, subway stations and even certain enclosed office spaces, surgical or intensive care units and laboratories.” [1]

We can easily see if we aren’t getting time outside in natural sunlight, we are getting much less brightness exposure than we were evolved to receive daily!

Circadian Rhythm Disfunction, Sleep Deprivation, Melatonin Suppression

Our circadian rhythm is the internal “clock” that our body follows for biological functions like hormones and sleep signals. Our body doesn’t understand the human concept of “time” for these critical functions, but it is designed to sync with the brightness and spectrum of outdoor daylight and night.

Bright Light Morning

Our bodies start their circadian "clock" with sunrise.

Lack of bright light exposure during the day has been found to disrupt sleep, melatonin production, and circadian rhythms.[1] Combined with too much artificial light at night from our screens and phones, it is a double-whammy to our sleep cycles.

blue light night sleep phone

Lack of bright lights during the day makes us more sensitive to light at night.

It is well stated in this quote below:

“For example, low light exposure during daytime sensitizes the system for light exposure in the evening as demonstrated by greater melatonin suppression in the evening when subjects had spent their preceding daytime hours in dimmer light… Low or aberrant light exposure during daytime thus may contribute to circadian misalignment, even in healthy persons not performing shift work.” [1]

Meaning that our eyes and brains adapt to low-light exposure during the day by becoming even more sensitive to light at night, especially blue light. Thus, furthering the sleep cycle disruption and lack of melatonin production in the body.

Diseases and Symptoms of Sleep Deprivation

When lacking in sleep, most of us have felt the natural grogginess, daytime sleepiness, and lack of alertness the next day. In addition to those acute symptoms, when we lack critical endogenous antioxidants like melatonin and other important circadian-rhythm related hormones are out of whack – eventually we will suffer long-term disfunction.

Lack of sleep tired groggy sleep deprivation

Here are some documented symptoms and conditions related to Sleep Deprivation according to one study.

Short-Term symptoms:

High Stress Response
Depression and anxiety
Loss of attention, poor executive function, high emotional reactivity
Loss of memory formation
Poor decision-making, poor judgement, and risk taking

Chronic (long-term) symptoms:

Cardiovascular issues
Metabolic syndrome (obesity, diabetes)
Cancer
Death (all-cause morbidity)

[2]

Another study found that seasonal variations in testosterone levels was related to changes in sleep duration and habits. https://pubmed.ncbi.nlm.nih.gov/15669539/

It may very well be that many of our mysterious “age-related” chronic diseases may stem from a lack of sleep. Or at least be feeding into a vicious cycle of poor sleep and health issues.

Desperate for a Solution

There is no doubt the modern world suffers an epidemic of sleep deprivation. In addition to a long list of unexplained chronic diseases, we see an ever-growing commercial market of “sleep aids” from everything from highly marketed pillows, bedsheets, beds – to biohacks like sleep-trackers, bed coolers, mouth-tape, nightlights, supplements, and blue-blockers.

Sleep Deficiency Disease

Could the most important sleep solution simply be to get more sunlight and bright light during the day? Lets take a look at the clinical studies.

Bright Lights can improve light deficiencies and diseases

Obviously if we are deprived of a nutrient and suffer a disease of deficiency from it, simply restoring the nutrient into the diet can help reverse the disease and symptoms. Like treating Scurvy with Vitamin C, it might be obvious that we need to implement bright lights to improve some disease conditions related to lack of sleep, melatonin, and circadian rhythms.

Some conditions that Bright Light Therapy has been investigated to improve:

Seasonal Affective Disorder (SAD): https://pubmed.ncbi.nlm.nih.gov/31574513/

Depression: https://pubmed.ncbi.nlm.nih.gov/21764874/

PTSD: https://pubmed.ncbi.nlm.nih.gov/30995350/

ADHD: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6746555/

Testosterone: https://www.sciencedirect.com/science/article/abs/pii/S0924977X16316856?via%3Dihub

Type 2 Diabetes: https://pubmed.ncbi.nlm.nih.gov/33851274/

Weight, BMI, Hunger Hormones, and Metabolism: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0092251

Well-Being and Sleep: https://pubmed.ncbi.nlm.nih.gov/33519670/

Parkinson’s Disease: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7224174/

Alzheimer’s Disease: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8119443/

Traumatic Brain Injury (TBI): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7861530/

Bipolar Depression: https://pubmed.ncbi.nlm.nih.gov/33034127/

Cancer Survivors: https://pubmed.ncbi.nlm.nih.gov/29127575/

We can see that there is a wide array of diseases that can benefit from Bright Light Therapy, and many of them overlap with the benefits reported from Red Light Therapy!

It could be possible that many benefits people are getting from their red light panels are from the Bright Light Therapy benefits, not just the Photobiomodulation benefits.

Bright Light Therapy Dosage

Just like Red Light Therapy, with Bright Light therapy we want to know how to dose it properly. With bright light therapy dosage we want to know:

The Wavelengths or Spectrum emitted
The Lux (at treatment distance)
How Long to Use It
When to Use It

Most studies with Bright Light Therapy are using a White Light to simulate the full-spectrum of the sun. Often the spectrum is high-Kelvin like between 4000K to 6000K to simulate noontime sun and be enriched with blue light.

Light Box Bright Light Therapy Sleep Deprivation

Typical bright light therapy employs bright white light boxes emitting a sufficient amount of lux for a fixed amount of time.

Some studies or devices are simply using single colors using Blue, Cyan, or Green light for bright light therapy also, since they know those wavelengths have the strongest impact. [3]

The Lux, or brightness, seems to be most important. Perhaps more important than spectrum. Most studies seem to use between 1,000 to 10,000 Lux.

The dosage time for the Bright Light therapy dose is usually between 20 minutes to 2 hours. Usually for lower Lux, they might use longer times like 1-2 hours. For high Lux they could use only 20 to 30 minutes.

The time of day is usually the morning or early afternoon. This way to simulate the brightness of the sun to align our body clock. We wouldn’t want bright light therapy at night since that would give us the wrong signals to keep us awake.

Do Red Light Panels also Deliver Bright Light Therapy?

Most people agree that red light has the least impact on shifting circadian rhythms (which is why we use ambient red lights at night). In fact, many Bright Light Therapy studies use dim red light as the “control” group!

However, we do find some studies that high-brightness red light can also suppress melatonin production in a similar way as white or blue light does. [4]

So how much Lux does the average Red Light Panel deliver? Is it enough to give us Bright Light Therapy benefits too? Well, it depends on the wavelengths and power emitted.

There are a few ways to determine Lux from a device:

Have a 3^rd party measure Lux at various distances away from the panel.
Measure the total lumens and divide by the meters squared (m^2) of light coverage.
Measure lux with a cheap light meter. (noting that there are inaccuracies with cheap lux meters and trying to measure monochromatic (red) lighting).
Use the 3^rd party measured Watts or Spectral Intensity and multiply by the Lumens/Watt conversion factors in the charts we mentioned earlier (also noting inaccuracies with assumptions and calculations compounding errors).

For example, from our 3^rd party data we can estimate our GembaRed Groove emits 1270 Lux at 6 inches away, and the GembaRed Beam emits 6716 Lux at 6 inches away.

The GembaRed Beam with it's narrow beam angle 660nm Red LEDs is quite bright and can deliver high brightness even from far away.

Regardless of the method we use to estimate Lux, we can tell that most red light panels can certainly offer Lux in the range of 1,000 to 10,000. At the very least, the brightness is much higher than typical indoor lighting.

So, if we are using our Red Light Therapy on our face or eyes and being mindful of eye safety, then we can certainly be getting some Bright Light Therapy benefits also!

Issues with Standard Bright Light Therapy

Many Bright Light Therapy devices on the market might be claiming to be emitting 10,000 Lux. But is that the Lux emitted at the surface of the device? Or the Lux at the actual treatment distance? Similar to how many red light panels are claiming >100mW/cm^2 at the surface, but not telling you the real intensity at the recommended treatment distance.

With the bright white lights and blue lights traditionally used for Bright Light Therapy, we have to be careful of Blue Light Hazard as defined by the CIE. Where short-wavelength blue light is understood to cause photochemical breakdown in the eyes making Bright Light therapy somewhat problematic.

We even know that Neutrogena had to recall their face masks due to potential blue light damage to the eyes, and one study investigated a case of eye damage after using a similar mask product. [5]

There has been a review of relative eye safety with bright light therapy, showing between 0% to 45% of participants complained of ocular discomfort and vision problems. They found there was no evidence for ocular damage due to light therapy, and concluded it is generally safe for physically healthy individuals. [6]

Another study indicates not staring directly at the Bright Light Device, but look off at least a 30 degree angle from the light (similar to what we recommend for Red Light Therapy). Common side effects include headache, eye strain, and nausea. Precautions include people with glaucoma, cataracts, retinopathy, and anyone with photosensitizing medical conditions or drugs. [7]

This is why we might consider relatively lower lux (1,000 to 5,000 lux) for longer time, and preferably from cyan or red light for eye safety would be optimal to avoid problematic situations with short-wavelength blue light.

Conclusions

Bright Light Therapy is another exciting application of using light for health! It seems we could be spinning our wheels with many “sleep-gadgets” when one of the most important things to do for our circadian rhythm is to get more bright light exposure during the day.

It is clear that a lack of sleep not only degrades our physical performance and mental acuity in the short-term, but long-term consequences of insufficient sleep includes many modern diseases, mood disorders, and death.

We see that many of the conditions and diseases studied for Bright Light Therapy have symptoms in poor sleep quality and insomnia. So whether the disease was caused by lack of sleep, or the poor quality sleep is caused by the disease – Bright Light Therapy might be the important intervention that helps mitigate the downward spiral of degenerative disease progression and improve quality of life.

Reducing and reversing these sleep deprivation risks can be as simple as going outside in the sun several times a day, especially in the morning.

Sunlight Bright Light therapy depression mood SAD sleep

If getting out in the sun isn’t accessible or convenient, we think starting with a Red Light Panel aimed at the face can be a safe and effective way to deliver Bright Light Therapy. Then perhaps graduating into a bright White, Blue, or Cyan light box used responsibly for eye safety.

This is just one more way that we can use Red Light Therapy to benefit us. Not only for direct Photobiomodulation mitochondrial benefits, but as a form of Bright Light Therapy to support our circadian rhythm and sleep cycles.

Thanks for reading! If you liked this post, you may also like our post about the best times of day to use red light therapy.

References:

Kawasaki A, Wisniewski S, Healey B, et al. Impact of long-term daylight deprivation on retinal light sensitivity, circadian rhythms and sleep during the Antarctic winter. Sci Rep. 2018;8(1):16185. Published 2018 Nov 1. doi:10.1038/s41598-018-33450-7

Impact of long-term daylight deprivation on retinal light sensitivity, circadian rhythms and sleep during the Antarctic winter (nih.gov)

Medic G, Wille M, Hemels ME. Short- and long-term health consequences of sleep disruption. Nat Sci Sleep. 2017;9:151-161. Published 2017 May 19. doi:10.2147/NSS.S134864

Short- and long-term health consequences of sleep disruption (nih.gov)

Lockley SW, Brainard GC, Czeisler CA. High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light. J Clin Endocrinol Metab. 2003 Sep;88(9):4502-5. doi: 10.1210/jc.2003-030570. PMID: 12970330.

High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light - PubMed (nih.gov)

Hanifin JP, Stewart KT, Smith P, Tanner R, Rollag M, Brainard GC. High-intensity red light suppresses melatonin. Chronobiol Int. 2006;23(1-2):251-68. doi: 10.1080/07420520500521988. PMID: 16687299.

https://pubmed.ncbi.nlm.nih.gov/16687299/

Kim TG, Chung J, Han J, Jin KH, Shin JH, Moon SW. Photochemical Retinopathy induced by blue light emitted from a light-emitting diode Face Mask: A case report and literature review. Medicine (Baltimore). 2020 Jun 12;99(24):e20568. doi: 10.1097/MD.0000000000020568. PMID: 32541484; PMCID: PMC7302677.

https://pubmed.ncbi.nlm.nih.gov/32541484/

Brouwer A, Nguyen HT, Snoek FJ, van Raalte DH, Beekman ATF, Moll AC, Bremmer MA. Light therapy: is it safe for the eyes? Acta Psychiatr Scand. 2017 Dec;136(6):534-548. doi: 10.1111/acps.12785. Epub 2017 Sep 10. PMID: 28891192.

https://pubmed.ncbi.nlm.nih.gov/28891192/

Campbell PD, Miller AM, Woesner ME. Bright Light Therapy: Seasonal Affective Disorder and Beyond. Einstein J Biol Med. 2017;32:E13-E25.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6746555/

http://hyperphysics.phy-astr.gsu.edu/hbase/vision/efficacy.html

https://en.wikipedia.org/wiki/Daylight

10.

https://www.engineeringtoolbox.com/light-level-rooms-d_708.html

11.

http://www.dfisica.ubi.pt/~hgil/FotoMetria/HandBook/ch07.html

Photo Credits:

- Indoors On Computer - Photo by Andrea Piacquadio from Pexels

- Blue Light at night - Photo by Sharad Kachhi from Pexels