LED light therapy started as a NASA technology developed for feeding plants in space but it is now available to the public in a variety of devices, ranging from full-body beds – much like tanning beds – for treating the whole body, down to small targeted pens that are great for treating acne. The uses range from wound healing to reducing cellulite to treating anxiety and depression. Red light therapy’s ability to reduce inflammation makes it an effective tool in treating different forms of arthritis.
What is Red Light Therapy?
Red light and near-infrared (NIR) light therapy involve using wavelengths of light in the 660 nm (red) to 890 nm (near-infrared) range, a portion of the light spectrum that is considered “bioactive.” It is administered with either low-level lasers or LED lights. You may have also heard this process referred to by any number of names, including:
- photobiomodulation (PBM)
- low-level light therapy (LLLT)
- soft laser therapy
- cold laser therapy
- photonic stimulation
- low-power laser therapy (LPLT)
It is believed that RL and NIR light therapy works by causing a biochemical effect in cells that strengthen the mitochondria. The mitochondria are the powerhouse of the cell. A cell’s energy is created in the mitochondria as adenosine triphosphate (ATP). Greater ATP production results in more energy for the cell to function more efficiently and repair damage.
Red light therapy doesn’t cause damage to the skin’s surface, which differs from laser or intense pulsed light (IPL) therapy. Laser and IPL work by causing damage to the outer layer of skin, inducing tissue repair. Differently, red light therapy penetrates only about 5 millimeters into the skin, directly stimulating cell regeneration.
Other Light Therapy
If you have ever heard of a “light box” or light therapy, this is a different treatment from red or NIR light therapy. Light therapy is exposure to light that is brighter than indoor light. Exposing people to light for 30 minutes a day can help stimulate a change in the levels of chemicals and hormones within the body that affect mood.
Light on this wavelength (400 nm to 480 nm) can help to regulate sleep patterns, improve mood, increase cognitive performance, and regulate hormones. It is used to treat depression, seasonal affective disorders, and sleep disorders.
The Mechanisms of Red Light Therapy
There are two basic mechanisms of red and NIR light therapy.
Mechanism #1: Stimulating Mitochondrial Energy Production
These wavelengths of light are able to penetrate into cells and activate the mitochondria. This activation directly leads to increased cellular energy production. The mitochondria are the batteries that fuel all the processes of the organs and are critical to health, disease prevention, energy levels, and longevity.
Cytochrome c oxidase is part of the respiratory chain in our mitochondria responsible for producing ATP, which is cellular energy. When red/NIR light hits the photoreceptor cytochrome c oxidase, it helps mitochondria use oxygen more efficiently to produce ATP.
It is believed that nitric oxide builds up in the mitochondria and competes with oxygen. Nitric oxide binds with cytochrome c, preventing oxygen from binding with cytochrome c to produce ATP. Red and near-infrared light keeps nitric oxide from binding with cytochrome c, allowing oxygen to do its thing.
Mechanism #2: Hormesis
Hormesis is the process by which a transient metabolic stressor stimulates adaptations that improve health. One good example of this process is exercise. When you exercise, you stress the body and temporarily increase reactive oxygen species (free radicals).
In response to this increase, the body adapts with things like improved cardiovascular efficiency, improved blood circulation and delivery to the muscles, and strengthening and growing the mitochondria.
Hormesis also downregulates the genes involved in chronic inflammation and oxidative stress, which are key elements of aging and disease, while upregulating genes involved in energy production and the internal cellular antioxidant defense system.
Temporarily stressed mitochondria signal back to the nucleus of the cell, where DNA is located. The nucleus uses this information to determine which genes are switched on and off. While most people think our genes control what happens in our cells, our mitochondria are actually responsible for generating signals based on environmental conditions, a process known as “retrograde signaling,” and dictating which genes are expressed.
The transient increases in free radicals from red/NIR light activates many of the same cell defenses that exercise does. Red/NIR light generates free radicals that activate the transcription factor NF-kB, promoting a very low-level inflammatory response. This engages a mechanism called the NRF2 pathway and the Antioxidant Response Element.
Red Light Therapy for Arthritis
There are many clinical studies showing the effectiveness of red light therapy in treating arthritis. A double-blind study conducted by the National Institute of Health stated:
“Our measurement results provide evidence that treatment with the active LLLT probe resulted in significant improvement for all evaluated parameters. In the placebo LLLT group, we found nonsignificant changes in joint flexion and pain. In the active LLLT group, we found significant improvement with regard to joint flexion, pain, and pressure sensitivity in the active group in comparison with the placebo group at the times examined. The positive effects obtained from active LLLT still persisted 2 mo after treatment. The lack of effect on knee circumference was expected and has not been demonstrated with other therapies. In the placebo LLLT group, three patients gave an account of an explicit reduction in their complaints, which is in line with placebo improvement in studies of other KOA therapies.”1
In a different study, Alves & colleagues used a rat model of osteoarthritis produced by intra-articular injection of the cartilage-degrading enzyme papain to test 810-nm LLLT. A single application of LLLT produced significant reductions in inflammatory cell infiltration and inflammatory cytokines 24 hours later. “These results provide additional justification for the use of LLLT (especially near-infrared laser that has the tissue penetration required for joints) as a treatment for osteoarthritis.”2
Soleimanpour & colleagues studied the effect of low-level laser therapy on knee osteoarthritis. The results of their study concluded, “In the current study, a significant reduction was observed regarding the nocturnal pain, pain on walking and ascending the steps, knee circumference, the distance between the hip and heel, and knee to horizontal hip to heel distance at the end of the treatment course.”3
Increased Range of Motion
Not only does RLT decrease knee and joint pain, but it has also been found to increase the range of motion. 4
A 2017 study in Lasers in Medical Science assessed knee cartilage in animal studies. They found red light very significantly reduced pain and improved knee cartilage regeneration through biochemical changes. 5
In a double-blind, placebo-controlled experiment in 2013, European researches examined the pain levels in patients with meniscus tears (meniscal pathology). As a result they found, “Treatment with light therapy was associated with a significant decrease of symptoms compared to the placebo group: it should be considered in patients with meniscal tears who do not wish to undergo surgery.” 6
General Knee Pain
Red light therapy has also been found to treat general knee pain not related to arthritis. A review in The Australian Journal of Physiotherapy examined 11 clinical trials of light therapy for chronic joint disorders of the knee. Across all studies, it reduced pain while improving overall joint function. 7
Hand and Wrist Pain
A 2016 study in Lasers in Surgical Medicine looked at the effect of RLT on the hands of 34 people with the bony growth and swelling conditions known as Bouchard’s nodes & Heberden’s nodes. The researchers found “significantly reduced pain & ring size and increased range of motion” and that “the effects were very large.” 8
Red light therapy has even been found to reduce morning stiffness by 27.5 minutes in participants, along with increased hand flexibility. 9
The evidence for the benefits of red light therapy continues to grow. Health benefits continue to be studied, including the effects on wound healing, acne, anxiety, depression, weight loss, bone health, eye health, mental and cognitive functions, pain relief, fertility, and many more. Its ability to be used as an anti-inflammatory while stimulating the production of collagen makes it an effective tool for combating arthritis in a truly non-invasive way.
The Science Behind Red Light Therapy
While no side effects have been discovered with red light and near-infrared light therapy, it is important to consult your physician before beginning any new medical treatments or regimes.
For more information on red light therapy you can check out my other blogs, “What Is Red Light Therapy?: Benefits, Side Effects, and How To Use It” and “How Does Red Light Therapy Work?”
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