Red Light Therapy For Sleep: The Science of Sweet Dreams

In this blog post, I explain the current science and show you some expert opinion on red light therapy for sleep. I'll also tell you about the best devices for red light therapy for sleep, whether red or amber lights in the bedroom are a great idea, and more.

But, let's start with the basics:

How Red Light Therapy Works For Sleep

Red light therapy works because the light doesn't just hit your skin but penetrates into your body. That way, the red and near infrared affect you at the cellular level. Red light therapy can lower inflammation across the body, for instance, while increasing energy production.

And, that increase in energy production results in many processes in the human body running much more smoothly. You can think about energy as the universal currency within biological systems - the more energy you have, the better you perform and feel.

Besides energy, many other processes are influenced by light as well. Examples here are the circadian rhythm - the circa 24-hour day and night cycle in your body. And, all of these processes that are affected up to the cellular level also influence sleep.

Below, I'll consider the four main studies that are now published on red light therapy and sleep. These studies explain in detail what sleep-related benefits you can expect:

4 Benefits Of Red Light Therapy For Sleep

Does red light therapy work with sleep? Current science shows that there are benefits of red light for sleep–but not a ton of studies are available on the topic. The studies that do exist, however, are extremely helpful. In total, there are four main studies that look at the effects of red light therapy for sleep quality. I'll consider these studies one by one in detail below:

Study 1: Better Mood, Less Drowsiness, More Quality Of Life

A 2022 study used infrared light only to improve sleep quality (1). That near-infrared light was emitted at the 850nm wavelength. In total, 56 participants were included in the study. All participants had mild sleep complaints. Exposure to the near-infrared occurred five times per week for four weeks. The light therapy was applied in the morning time.

Also, the light therapy was used in both the summer and winter time to deal with seasonal variation. That turned out to be a great choice from the researchers, as decent results were found when red light therapy was applied in the winter but not in the summer.

The explanation here is that many people tend to get much more light exposure during the summertime. The benefits of red light therapy are thereby decreased, the argument goes.

The red light therapy didn't lead to improvements in sleep. But, daytime improvements were noted in this study. Researchers write:

"The results showed PBM treatment only at 6.5 J·cm⁻² to have consistent positive benefits on well-being and health, specifically improving mood, reducing drowsiness, reducing IFN-γ, and resting heart rate. This was only observed in winter. No significant effects on sleep or circadian rhythms were noted." (1).

The full text of the study explains a bit more about why this result was found (2).

First up, humans spend 85% of their time indoors, thereby not getting much sunlight exposure. That trend is especially severe in wintertime. Building isolation to save energy also blocks most near-infrared, so that you won't get exposure through windows either.

The near-infrared light was used on the hands, neck, and face of study participants, so it wasn't a full-body setup. Instead, a desk lamp was used. The device also emitted only 5 mW/cm2 as a dose, but was emitted over many minutes and even hours in case of the higher dosages. The study setup was actually extremely extensive if you read the full text of the study (2)

Nevertheless, benefits were found, but only for wakefulness, not sleep quality.

I do think different effects would have been found with a higher dose for deeper tissue treatment and full-body exposure. But fortunately, we can rely on other studies as well:

Study 2: Less Sleep Requirement (Implying Faster Recovery) And More Deep Sleep

Next up, a fascinating study using the NovoTHOR red light therapy device (3; 4). The NovoTHOR is the gold standard for red light therapy beds on the market right now. The NovoTHOR is mainly marketed towards the medical industry but includes clinics as well.

(If you're interested in a NovoTHOR, mention the name Alex Fergus!)

This study is also fascinating because elite female soccer players were included. The women wore an Oura Ring to track sleep quality and also a GPS monitor during training.

So here are the amazing results and conclusion section of the research paper - I'll explain this in plain English below:

"Within-subject comparisons of cardiorespiratory physiology, sleep duration, and sleep composition were evaluated the night before and after PBMT sessions completed as a standard of care for team recovery. Compared to pre-intervention, mean heart rate (HR) was significantly lower the night after a PBMT session (p = 0.0055). Sleep durations were also reduced following PBMT, with total sleep time (TST) averaging 40 min less the night after a session (p = 0.0006), as well as significant reductions in light sleep (p = 0.0307) and rapid eye movement (REM) sleep durations (p = 0.0019). Sleep durations were still lower following PBMT, even when controlling for daily and accumulated training loads. Enhanced cardiorespiratory indicators of recovery following PBMT, despite significant reductions in sleep duration, suggest that it may be an effective modality for maintaining adequate recovery from the high stress loads experienced by elite athletes." (3)

What do these outcomes mean in plain English? First up, the elite soccer players would naturally reduce their sleep time even though they trained very hard.

And, not only was sleep time reduced. The resting heart rate - a sign of how stressed your body is - decreased, which is a favorable recovery sign. And, heart rate variability - the interval between heart beats - also showed signs of quicker recovery. The exact biological mechanisms for these effects aren't given in this study, nor is it described in the scientific literature.

Overall, though, the outcome of this study is extremely promising, as even elite athletes may have significant benefits by shortening their sleep needs, thereby implying improved sleep quality. This study is from 2022 as well

Next up:

Study 3: Red Light Therapy Improves Sleep Quality And Cognitive Performance For People With Cognitive Decline

I can't find a full text of this 2022 study so I can't do a full analysis of the outcome here (5). Suffice it to say that red light therapy was applied to the prefrontal cortex, which is the brain area above your eyes, in patients with subjective cognitive decline.

The study participants were split into a placebo and treatment group. After five days, the treatment group saw increases in the amount of deep and REM sleep they received, while the percentage of light sleep declined.

The participants receiving the light therapy treatment also performed better at a brain test that uses working memory and processing speed called "dual n-back". The prefrontal cortex plays a major role in the performance on that test.

Overall, red light therapy does improve sleep quality in this study.

Study 4: Female Basketball Players Improve Melatonin Levels, Endurance, And Sleep Quality With Red Light

Next up, a study with 20 athletes of the People's Liberation Army (6; 7). The athletes were 18 years old on average and play basketball. Ten of the athletes received red light therapy and ten a placebo. Sleep quality was measured with the Pittsburgh Sleep Quality Index (PSQI). The PSQI is a widely used valid and reliable sleep measurement tool, although imperfect (8; 9; 10).

The athletes also had their melatonin levels measured and did a 12-minute run test. In the intervention group, red light therapy was applied daily for two weeks straight. The red light therapy lasted 30 minutes and was applied with a bed. The wavelength used was 660nm. A 30 J/cm2 dose was applied, which is great for deeper tissue treatment.

Here's the outcome of the study:

"The 14-day whole-body irradiation with red-light treatment improved the sleep, serum melatonin level, and endurance performance of the elite female basketball players (P < .05). We found a correlation between changes in global Pittsburgh Sleep Quality Index and serum melatonin levels (r = -0.695, P = .006)" (6).

So, melatonin levels, endurance performance, and sleep quality all improved with full-body red light therapy.

The full text of the study also shows some very nice differences - that can be achieved in just 30 minutes of full-body treatment per day for two weeks. For instance, check the difference in the PSQI score - where a lower score signifies better sleep:

As you can see, the PSQI score improved from six points to four points in the intervention group. In the placebo group, the PSQI got slightly worse. Then there's the melatonin levels measured in the blood:

Melatonin levels, as you can see, become significantly higher in the group receiving the red light therapy full body treatments. Lastly, there's endurance performance:

Here too, there's a significant increase in the performance of the red light therapy treatment group.

Overall, these improvements in sleep quality, melatonin status, and exercise performance after full body red light therapy are extremely promising for sleep.

But how about other studies that don't necessarily use red light therapy? I'll briefly consider this topic:

Other Insomnia & Light Therapy Studies?

So what's the insomnia light therapy link? This option is circadian light therapy - where you use bright light in the morning and during the day to improve sleep at night.

Blue and green light are beneficial here to promote wakefulness. But even ultraviolet light has extensive benefits of its own. So, unless you're living at a very high latitude where it's incredibly dark in the winter, sunlight is still your best option.

So let's explore some other studies that consider insomnia, light therapy, sleep quality, and their interaction:

• Sunlight has an amazing track record for helping people sleep better (8; 9; 10; 11; 12; 13; 14; 15). Sunlight is great for sleep onset, duration, and quality, in children, adults, and the elderly. Sunlight also helps your body build vitamin D in the skin--while vitamin D deficiency is related to sleep problems.
• Bright light in the morning can also help sleep - even if it's not from the sun (16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26). Mood improves here, as well as daytime wakefulness. And, sleep quality at night is enhanced as well. You can use an SAD lamp for this effect, or even simply an old-fashioned strong halogen floodlight or several high-wattage incandescent lamps.
• Although technically not light therapy, I recommend avoiding bright light at night (27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38). Blue and green light surpress melatonin production in the evening and at night - common sources are screens and artificial light sources. Light exposure at night is also detrimental to sleep quality - the green and blue are the main cultprits here again. I mention this because I return to the topic of the benefits of sleeping with red light later on.

So it's not just red light therapy for sleep that works - other light therapy sources can improve sleep quality also. Also, if you're interested, check the video below where Alex Fergus explains the science on this topic:

Now, let's consider the timing of your red light therapy sessions:

Timing Matters: When To Use Red Light Therapy For Sleep?

Currently, there are no studies comparing red light therapy for sleep in the morning, afternoon, or night. So, the best option there is to rely on anecdotal evidence of experts.

For the best timing, I simply recommend experimenting. A pattern which has been observed in many people is that some people do really well with red light therapy in the evening, while for others, it's overstimulating.

If you're getting overstimulated after a red light therapy session - which can be explained through a dramatic increase in energy production, for instance - then it's better to do your red light therapy sessions during the morning, afternoon, or early evening.

If you feel great and are able to sleep perfectly after a red light therapy session, even though it's in the evening, by all means keep doing what you're doing! Until we've got more studies on this topic, there are no strict recommendations that can be made in this case.

Also, for the best results, get a wearable sleep tracker. The Oura Ring is an option many people love - a device that's highly accurate and continues to improve in its deep sleep and REM sleep tracking.

Next up:

Is There A Best Red Light Therapy Device for Sleep?

So, what's the best red light therapy device for sleep? There's not a simple answer here. The studies I've discussed before all use a different setup. With setup, I mean that varying devices are used, which emit different wavelengths of red light, for different durations and intensities, with different participants, and so forth.

Also, let's have a look at the red light therapy devices for sleep that have been used in the studies so far:

• The first study used a desk lamp, with 5 mW/cm power output, with 850nm light (1).
• The second study I considered uses the NovoTHOR bed (3). The NovoTHOR emits 660nm and 850nm light and around 16.7 mW/cm2, but very evenly across the entire body.
• Regarding the third study, I cannot see much regarding the setup (5). The only thing known was that the red light therapy was applied to the forehead.
• Then, lastly, the fourth study used a full body bed as well but with 660nm only (6).

Out of these studies, the full body red light therapy applications showed the best results by far. Why? Applying red light therapy to the head leads to decent results, but full body seems better, given the studies above.

So let's check a few options if you want a big enough setup for maximum results. I'll begin with Alex Fergus' comparison of the bigger panel on the market:

I next up recommend checking this red light therapy panel comparison of 2023 as well, for an update.

Also, if you want to understand the concept of full-body treatment better, I recommend checking the following two videos that I post below. These videos explain the coverage that you can expect when you're using a red light therapy panel:

Next up, the same experiment with multiple panels - essentially a full-body setup:

Again, you'll ideally want full body coverage as well as a higher power output, for deeper pentration into the body.

Moving on to another important topic:

Expert Tips How To Use Red Light Therapy For Sleep

Next up, what do several experts say about how to use red light therapy for sleep? The topic is complicated. As stated before, you'll have to experiment with using red light therapy either during the daytime or early evening. Some people do really well with red light therapy before bed but it's not the rule.

Secondly, ensure that you're using a deep tissue treatment protocol. Most companies now supply you with information on how to use products for deep tissue treatment. The reason I recommend deep tissue treatment is because the studies with the best outcomes using full body red light therapy beds show results with higher power outputs.

Thirdly, you'll have to realize that red light therapy is just one factor among many affecting sleep quality. I don't want to go too deeply into this topic, but many other factors can have a massive influence on sleep quality. Examples are your nutritional levels and magnesium levels in particular, whether you mouth breathe at night or through your nose, air quality, potential noise pollution, room temperature, toxins in the mattress or other fabrics in your sleep environment, how well you treat your circadian rhythm, EMFs, (chronic) psychological stress, and many more.

Good or bad sleep is not determined by one factor. And yet, red light therapy will move the needle into the right direction. You'll still have to consider red light therapy for sleep one tool in the toolbox though!

Hence, if you've got horrible psychological stress, are living to a noisy and pollutive road, have a magnesium and zinc deficiency, and breathe through your mouth and snore, red light therapy won't fix all your problems. But, you will sleep slightly better, which is a huge benefit for many people already.

Sleeping With Red Light Therapy: Is It a Good Idea?

Sometimes people ask me: "But isn't sleeping with red light therapy a good idea?" Or "Why shouldn't you have red lights on at night?"

The simple answer is that you can, especially if the light isn't too bright. Bright light sometimes overstimulates people, even if it's red light. But red light at night is the healthiest option you can pick out of all visible colors.

The reason is that red light is still visible while not suppressing melatonin levels in your brain. You can use specialized red light bulbs for sleep that aren't too intense. So, a small red or amber bed light is great. But, you don't need to have a red light therapy panel activated at the full intensity - that's most likely counterproductive.

Overall though, I do really support red light bulbs in the evening and at night. The more artificial blue and green light you can block out from the environment, the better your sleep will be.

Conclusion: The Red Light Therapy Sleep Benefits Are Truly Exciting

Hopefully, I convinced you that the red light therapy sleep benefits are the real deal. Even without many scientific studies, you can still learn a few lessons from them. Full-body treatments are better than treating smallar parts of the and you'll need decent power density for the full benefits.

Also, red lights for bedroom are great too for allowing your melatonin levels to rise. You can use such bulbs throughout the house in the evening for the best effects. Lastly, for the best effects, get some natural light exposure from sunlight too, during the morning and afternoon.

Frequently Asked Questions

Below I'll answer a few frequently asked questions about red light therapy for sleep:

Can Red Light Therapy Cause Nightmares?

Sometimes people ask "does sleeping with red lights cause nightmares?" Or whether red light therapy causes nightmares. The answer here is no - the opposite should even be true, as you're moving your physiology towards that of more relaxation (the parasympathetic nervous system activation).

So, generally, nightmare risk should go down, not up. The exception is perhaps if you're psychologically frightened by the color red somehow because it looks austere. From the outside, your place can look like a haunted house if you activate red lights only at night.

Can I Use Red Light Therapy And Blue Light Therapy Together for Sleep?

Yes, during the day, you can use red light therapy and blue light therapy together for sleep. Blue light therapy tells your body it's daytime and improves your wakefulness.

Ideally, you shouldn't use blue light therapy at night because it can keep you up. Using blue light therapy at night is like drinking a cup of coffee before bed - for almost everyone, sleep quality tends to go down in that case.

What Other Colors of Light Can Enhance Sleep Besides Red?

Amber, found between 600 and 620nm light, is also frequently used as a sleep light. But, the effects are very similar to a red light. Both amber and red light don't surpress melatonin, so sleep quality improves.

Some people ask "does red light produce melatonin?" The answer is no here - red ligth allows melatonin to rise in your brain, as does amber, but it doesn't produce melatonin by itself.

Is It Safe To Use Red Light Therapy Daily For Sleep?

In the studies performed so far, red light therapy is safe to use daily for sleep, yes. Anecdotally, some people do better when they take a day off every week and don't use red light therapy seven days a week. Again, there is no hard science on this topic, so you'll have to use trial and error.

Does Red Light Produce Melatonin?

The absence of blue and green light in the human eye is what creates melatonin. So, red light by itself doesn't produce melatonin because you'll get the same effect in complete darkness.

Is Red Light Therapy Good For Babies' Sleep?

Technically, there are no studies on red light therapy for babies' sleep. However, an amber or red light in the babies' bedroom can be extremely helpful for creating a healthy sleeping environment, as their melatonin levels are also negatively affected if you've got green or blue lights in the room.

This is a post by Bart Wolbers. Bart finished degrees in Physical Therapy (B), Philosophy (BA and MA), Philosophy of Science and Technology (MS - with distinction), and Clinical Health Science (MS), has had training in functional medicine, and is currently chief science writer at Lighttherapyinsiders.com

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