Photobiomodulation, also known as RLT, increases muscle endurance and speeds muscle recovery.

John Iovine

Apr 12, 2020·8 min read

When I began researching Red Light Therapy (RLT) also known as photobiomodulation (PBM), I realized I needed this badly. Practicing martial arts at my age (65) is challenging. The aches and pains usually associated with working out amps up with age. As soon as my muscles cool off from the work out and drills, usually within an hour from leaving the Dojo, my muscles and joints ache.

For all the information presented in this article the following terms; Red Light Therapy, RLT, photobiomodulation and PBM mean one and the same, and may be used throughout the text interchangeably.

First photobiomodulation is not snake oil. The technology was adopted by NASA in the 1990s, as a methodology to increase wound healing for space faring astronauts. Today there are literally thousands of clinical, scientific peered review studies on the efficacy of Red Light Therapy (RLT) treatment for a wide variety of conditions.

One researcher I follow is Dr. Michael Hamblin. A Harvard University professor and the lead researcher at the Wellman Center for Photomedicine at Massachusetts General Hospital. He has published over 400 peer-reviewed papers. He has researched and written upon the use of photobiomodulation for wound healing, brain injury, hair regrowth, psychiatric disorders and arthritis. He is considered the foremost expert on Red Light Therapy and Photobiomodulation.

This article focuses on the effects of RLT on muscles.

1. Improves muscle endurance
2. Reduces muscle soreness (DOMS)
3. Improves muscle recovery
4. Reduces joint pain
5. Reduces inflammation

The clinical evidence is so overwhelming that some trainers, as well as professional, NFL and Olympic athletes are using it (1) for its muscle performance boosting benefits.

Photobiomodulation- For Beginners

The biochemistry involved with photobiomodulation is complex. We do not need to understand the how and why it works to enjoy the benefits. The same way you don’t need to be an auto-mechanic to drive a car. Still a little understanding goes a long way.

Remember from school, how your teacher described the mitochondria as the “powerhouse of the cell”. That hasn’t changed. And the power of RLT circles around the mitochondria. The mitochondria contain chromophores that absorb light at specific wavelengths. This absorbed light enhances the biochemical and metabolic process. Boosting the cells production of ATP, adenine nucleotide. ATP is the fuel the cell uses for energy. RLT also releases Nitric Oxide (NO) that reduces inflammation and dilates micro blood vessels enhancing circulation.

These effects enhance a cell’s ability to do what the cell was designed to do. So whether the cell is a muscle cell, nerve, skin cell, brain cell, etc., it pumps up the cell’s metabolism. This explains why clinical studies show positive results from photobiomodulation across a diverse range of medical disciplines.

Wavelengths of Light

Two most common wavelengths of light used in photobiomodulation studies are Red light between 630–680nm and Near Infrared (NIR) between 800–880nm. The LED’s or Lasers used in the therapy are tuned to a single wavelength within those ranges, typically Red 660nm and NIR 850nm.

Many LED panels used for RLT are composed of two types of LEDs, with one producing red light wavelength and the other producing near infrared (NIR) light wavelength. The LED’s are interwoven in the panel to produce even light of both wavelengths.

Depending upon the manufacturer each wavelength of light may be controlled by its own power switch on the panel.

Penetration Into The Body

The RLT light has been measured to penetrate up to 23 cm through the surface tissue to irradiate the muscle and bone.

When used on the head, only about 5% of the NIR light can penetrate the skin and skull to the brain. For more information on the positive effects of RLT on the human brain see my article; “How RLT Enhances The Brain”

From Lasers To LED’s

Much of the original studies used the monochromatic light from low powered lasers. LLLT (low level laser therapy). Later scientists like Michael Hamblin discovered that monochromatic LED work just as well as lasers.

Muscular Endurance (Pre-exercise)

This study was performed on ten professional male volleyball players. This double-blinded placebo-controlled crossover trial study used two wavelengths of light 660nm and 850nm. After a treatment of 42 joules of LED light at these two wavelengths, when treated the men increased the number of bicep contractions by 13% over a placebo. (Study).

Muscle Recovery (Post-exercise)

This study took seventeen young males with no previous experience with eccentric exercise and divided them into two groups. One group of eight (n=8) became the LEDT (LED Treated) group. The other nine men (n=9) became the Placebo group.

To induce muscle damage the subjects perform 30 eccentric contractions with 100% maximum voluntary contraction strength using their non-dominant arm. Immediately following the exercise, the LEDT group had their biceps treated with 20 joules of 630nm light. The placebo group went through the same protocol but did not have the LED lights turned on.

Results showed that the LEDT treated group had significantly less muscle soreness, muscle strength loss, and range of motion impairments at all time intervals of 24, 48, 72, and 96 hours after eccentric exercise. (Study)

The RLT Effect on Delayed Onset Muscle Soreness (DOMS)

The chart above was created from information in a study using two identical twins. The twins were monozygotic, and their genetic profile was checked before the experiment and confirmed. Their genetic code was essentially identical.

This was a blind study, neither twin knew which one was receiving the real treatment or the placebo. The real treatment was 5 watts of 850 nm light for 15 seconds equaling 75 Joules on each quadriceps. Both twins entered an intense leg exercise program for 12 weeks. This consisted of three training sessions per week. Each session were 40 repetitions (4 x 10) leg presses plus thirty repetitions (3 x 10) of leg extensions. (Study)

Supports Muscle Hypertrophy and Strength with Less Fatigue

I have written another PBM article that addresses muscle development and training. I mention it here to complete the overview.

RLT at 810nm provided to leg muscles before training workouts significantly increased both size and strength of muscles over exercise alone.

(Study)

Light Dosages

The dosage of light is important. It appears PBM light treatment is bi-phasic, meaning more is not always better. The general dosage recommended by Dr. Michael Hamblin is around is 10–20 joules per square centimeter (cm²). The dosage will vary depending upon the body part and effect you are looking to achieve. But according to Dr. Hamblin, 3X-4X the proper dosage may inhibit rather than help.

In fact, he believes one reason why some researchers fail to see positive results using photobiomodulation is that they are overdosing their subjects with light.

Rather than cut and paste RLT dosages in each article, I wrote a RLT dosage article and link to it.

Other Articles

I am writing a series of articles. Below are a few articles available on Medium and I will be adding more in the future.

1. How To Use RLT For Fat Loss
2. How To Use RLT For Muscle Building
3. How To Use RLT For Brain Cognitive Enhancement
4. How To Calculate RLT Dosage

My Own Results

Muscle recovery is hard for me to determine. Each workout is different, with the practicing of different drills at different intensities. I will use PBM and try to track this but I am not running studies on myself. I can only provide my anecdotal opinion, I’ll update this article with that information in a few months.

One incident that comes to mind is when my left knee started bothering me two weeks ago. It hurt more when walking downstairs than walking up. It hurt, but the pain wasn’t terrible. After suffering with it a few days, I knew PBM has good clinical results with reducing inflammation and joint pain, so I thought to myself why not give it a try?

My PBM Unit

I had purchased a high power 600 watt RLT unit to keep the exposure time down. 600 watts is the total power output. The light output is split; 300 watts at 660nm and another 300 watts at 850 nm.

At this light intensity, I only needed 3 minutes under the light to reach a 10–15 joule dose recommended by Dr. Michael Hamblin.

To treat my knee, I positioned my knee about an inch away from the unit. Using both light wavelengths, I put the RLT on for five minutes. At this distance I estimate the intensity of light at 120 mW/cm². For five minutes time is 300 seconds x 120 mW equals 36 Joules of energy. I felt a gentle warming on my knee, probably due to the NIR LEDs. I didn’t expect much to happen, especially with just one treatment. As I prepared to walk downstairs, I put my foot on the first step, and gently place my weight on my foot. Amazingly, most of my knee pain had disappeared. I thought to myself, “Oh wow is this real?” Next step down, I moved a little faster, same thing, just a twinge of knee pain.

The total light energy is 36 joules, but this is broken up into two wavelengths, 18 joules of 660 nm and 18 joules of 850nm light.

The 600 watt RLT unit I use is available on Amazon. It provides light in both 660nm and 850nm wavelengths of light.

Conclusion

I don’t want this to sound like an infomercial because it's not. But with the positive results I personally obtained with my knee, I am deploying this technology quickly and decisively. I am building a literal wall of RLT light. I am stacking RLT units on top of one another so that I can obtain a complete head to toe, full body exposure of 10–20 joules in three minutes. That’s three minutes per side, front and back, for a total time investment of six minutes.

I am impatient. If I were required to spend more than a few minutes PBM light bathing, I won’t do it. So for me it was essential to build a head to toe RLT.