Light Therapy for the Lymphatic System

What is the lymphatic system?

Of all the systems of the body, the lymphatic system is probably the most underappreciated and misunderstood. Many people have never even heard of it, and of those who have, most don’t really know what it does. Even medical doctors report that their understanding of the lymphatic system is “suboptimal”, and that the teaching of this system and its associated diseases in medical school was insufficient.

Anatomically, the lymphatic system can be thought of as a network of vessels and organs that carry a clear fluid called lymph. The system largely travels alongside the system of blood vessels in the body. The lymphatic system includes hundreds of lymph nodes, which can sometimes be felt superficially in regions like the neck, armpit and groin. The tonsils are considered lymph nodes, but due to their size are sometimes referred to as lymphoid organs. Other lymphoid organs include the bone marrow, spleen and thymus. Lymphoid organs produce cells called lymphocytes, which are immune cells. The lymphocytes are carried in the lymphatic fluid throughout the body. 

The lymphatic fluid (or lymph) is mostly produced by liver and intestines. In addition to lymphocytes, lymph also carries fat, proteins, and pathogens. It can also carry cancer cells, making the lymphatic system a potential route for cancer metastasis. This is why it is standard practice to biopsy lymph nodes near a tumor to determine if the cancer has spread. Lymph flows in one direction, upwards towards the neck, which requires the vessels to have one-way valves that prevent backflow and a pumping system that involves both extrinsic and intrinsic forces. Extrinsic forces include skeletal muscle contractions, while intrinsic forces involve contractions of lymphatic muscle cells. When pumping is impaired, lymph fluid will accumulate (usually in the extremities) and cause swelling, also referred to as edema.  

The lymph composition reflects the functions of the lymphatic system. These include: (1) carrying out many activities of the immune system (such defending against invading pathogens), (2) transporting and absorbing fats and fat-soluble vitamins, (3) maintaining fluid balance, and (4) removing cellular waste, which is recycled by the liver. These functions are essential to maintaining health, and impairment of lymphatic system function can cause a wide range of problems including (but not limited to) lymphedema (tissue swelling), autoimmune diseases, and cancer.

The lymphatic system can ultimately be viewed as inseparable from the immune system, although it also has additional roles that make it distinct. It can also be thought of as a “subsystem” of the circulatory system, because it absorbs plasma that escapes from the blood and that contains important nutrients which are returned to the bloodstream through lymphatic vessels. Lymphatic vessels dump directly into the circulatory system through the venous system. This happens in the neck, where the lymph dumps into vessels such as the subclavian vein. Between 8 and 12 litres of fluid per day is returned to the blood through the lymphatic system. 

Although it was previously thought that the lymphatic system was not found in the brain, a network of brain lymphatic vessels was recently identified. These vessels are found in the meninges, which make up the outer three layers of the brain and spinal cord. Meningeal lymphatics drain cerebrospinal fluid (which surrounds the brain) into lymph nodes in the neck and help to clear waste out of the brain. It is also a “pipeline” for immune cells. The lymphatic system in the brain has been termed the “glymphatic system” and is especially active during sleep. This system has been linked to brain diseases such as dementia, including Alzheimer’s. 

There are many ways to support lymphatic system health, such as with exercise and massage, which support the flow of lymph. Lymphatic system health is also supported by minimizing the intake of toxins through food, water, and the environment. Another supportive tool is red light therapy, which has recently been identified as an effective way to optimize the health of the lymphatic system and can be done at home using devices including panels and wraps.

What is red light therapy?

The term “red light therapy” usually describes the use of both red and near infrared light, although only the red light produced by the device is visible to the naked eye. Infrared light can still be perceived by the body as heat when it contacts skin. Red and near infrared light therapy is the application of artificially generated light in the red and near infrared spectral bands. 

Red and near infrared light are naturally produced by the sun, which gives off solar radiation. The term radiation describes energy that is transmitted in the form of waves or particles. The spectrum of light in our environment consists of both light we can see (visible light) and light that our eyes can’t perceive (invisible light). This is called the electromagnetic spectrum. The visible light spectrum is quite narrow, consisting of wavelengths that range from 400 to 700nm and span from violet to red in color. Red light is part of this visible light spectrum, while near infrared light is not.

While early research on light therapy used primarily lasers, more recent research has found that LED’s can also be used, which also have the advantage of applying light to a larger area of the body as well as an improved safety profile. The use of LED in red/near infrared light therapy devices has also greatly reduced the cost of treatment, making it something that can be done in the comfort of one’s own home. 

What is the evidence that that red light therapy affects the lymphatic system?

Before we dive into looking at some of the general mechanisms by which red light therapy affects the lymphatic system, let’s look at some of the research evidence that specifically demonstrates the utility of red light in treating disease via lymphatic system modulation. While this is a very new area of research, many compelling studies have shown red light therapy to be helpful in improving the function of this important system.

Glymphatic System – The glymphatic system of the brain is a key player in diseases of the brain, including dementia, Alzheimer’s, and Parkinson’s disease. The ability to clear waste from the brain is described as the glymphatic system’s “most central” function – which means that waste buildup will result when the system is impaired. Glymphatic system function declines with age and because of disease and trauma, such as stroke and traumatic brain injury. It is critical to brain health to support glymphatic function. 

Red light therapy was recently described as “a non-invasive neuroprotective strategy for maintaining and optimizing effective brain waste clearance” via the glymphatic system. As evidence, near infrared light has been shown to activate the glymphatic system in the brains of diabetic mice. Similarly, in animal models of Alzheimer’s Disease, application of both red and near infrared light increases glymphatic system activity and results in clearance of amyloid, which is a toxic protein. Red light therapy has been shown to be improve symptoms of Alzheimer’s disease and other forms of dementia in humans, and although these studies have not specifically looked at glymphatic function, it is likely that it is affected. 

Red light therapy has also been shown to improve glymphatic system function in brain injuries. In rats with experimentally induced intraventricular hemorrhage (which mimics stroke), application of near infrared light increases lymphatic drainage and speeds the rate of recovery. And in ex-football players suffering from chronic traumatic encephalitis, application of near infrared light caused lymphatic vessels in the brain to dilate, which would be expected to increase flow and clearance of waste from the brain.

Since this system is particularly active during sleep, using red light therapy during sleep or in the evenings might be most helpful. 

Lyphedema – Lymphedema is swelling that occurs because of lymph buildup. This usually happens in the legs or arms, but it can occur in other areas as well. Primary lymphedema is a result of a problem present from birth, while secondary lymphedema is acquired, usually from an infection, cancer, or as a consequence of cancer treatment. The underlying cause of lymphedema is disruption of the lymphatic system, which prevents the proper flow and drainage of lymph. Lymphedema is usually chronic and progressive, and symptoms can greatly affect quality of life.

Most research on red light therapy and lymphedema has focused on breast cancer patients. Breast cancer treatment often involves removal of lymph nodes from around the breast, and/or radiation, which can disrupt the flow of lymph out of the arm. In a review of nine studies using red light therapy to treat breast cancer related lymphedema, overall, both a reduction in size of the affected arm and pain was achieved. Eight studies used near infrared light while one used red light, and all but one study specified directing the light therapy to the armpit region. Three studies also targeted other areas on the arm. The observed reduction in arm size was expected to be clinically meaningful.

Red light therapy may also reduce lymphedema of the head and neck. Lymphedema in this area is usually caused by radiation in patients with head and neck cancers. Lymphedema here can be very problematic, causing problems with eating and swallowing. Red light therapy may help to reduce edema in the area, as well as to improve the condition of the skin. 

Inflammation – Inflammation is a hallmark of many diseases currently ravaging modern society, such as arthritis, ulcerative colitis, inflammatory bowel disease, heart disease, diabetes, cancer, Alzheimer’s Disease, and depression. Inflammation is also associated with acute diseases involving the heart, pancreas, liver, and other organs, as well as trauma and infection. Treatment of inflammation associated diseases makes up the majority of health care spending in the US, costing billions of dollars annually. The lymphatic system plays a key role in regulating inflammation, and increased activity of the lymphatic system has been associated with reduced inflammation since it helps to remove excess fluid.

Red light therapy’s ability to decrease inflammation has been well-established. As described by Dr. Michael Hamblin, former Associate Professor at Harvard Medical School, “one of the most reproducible effects of [light therapy] is an overall reduction of inflammation”. Studies have found that light therapy affects levels of many molecules involved in inflammation, including reactive oxygen species, reactive nitrogen species, and prostaglandins. Light therapy has even been found to reduce inflammation in the brain, known as neuroinflammation. 

Although the role of the lymphatic system in inflammation is well established, most studies using red light therapy to decrease inflammation have not specifically assessed its effect on the lymphatic system. However, when this relationship was investigated, it was found that application of near infrared light to lymph nodes caused a decrease in inflammation and related swelling. 

How does red light therapy affect the lymphatic system?

Clearly, red light therapy has many positive effects on the lymphatic system of the body and the glymphatic system of the brain. Research on precisely how red and near infrared light mediate these benefits is not extensive, but there are several general mechanisms that have been identified.

Relaxing Lymphatic Vessels – Red light therapy can induce the relaxation of lymphatic vessels. This happens through a process called vasodilation.  When lymphatic vessels are more relaxed, the flow of lymph is increased. This has been observed experimentally to occur in the glymphatic system of the brain. In the brain, increased vasodilation may allow larger molecules (such as the amyloid protein) to pass into the lymph, improving the clearance of waste. Vasodilation may be due to increased production of nitric oxide, which could act on smooth muscle cells that are the “motor unit” of lymphatic drainage. 

New Lymphatic Vessel Synthesis – Lymphangiogenesis is the process of formation of new lymphatic vessels. In a mouse model of lymphedema, application of red light therapy induced lymphangiogenesis, suggesting that in conditions where lymph flow is impaired due to lymphatic system damage, red light therapy may restore function by supporting the production of new lymphatic vessels. 

Activating Mitochondria – Mitochondria are found in cells throughout the lymphatic system. Mitochondria are right in molecules called chromophores, which absorb light. Specifically, red and near infrared light stimulate cytochrome c oxidase, a mitochondrial enzyme that produces ATP, the energy currency of the cell. This increases ATP synthesis which provides more energy to cells throughout the lymphatic system. Rd light therapy has been shown to modulate oxidative stress and reactive oxygen species production, which might improve the function of lymphatic system cells. 

Stimulating Lymphoid Organs – Lymphoid organs are affected by aging, which leads to impaired functioning of the immune system and increases susceptibility to illness. This primarily affects the thymus gland, which is found in the upper chest behind the sternum. Application of red light therapy to the thymus through the chest wall may support thymus health and decrease age associated changes and could perhaps support thymus function throughout the lifespan. Application of red light therapy to other areas, such as lymph nodes, may also support lymphatic system function through tissue stimulation.

How do I choose a red light device to affect the lymphatic system?

For at home use of red light therapy, the majority of products (especially the affordable ones) will use LED lights, rather than laser. While early light therapy research was done using lasers, LED lights have become much more popular over the last decade. In 2018, Dr. Michael Hamblin – the world’s leading light therapy expert – concluded that LED lights using comparable parameters to lasers performed “equally well”, which is very important because LED powered light therapy devices can be made at a fraction of the cost of laser devices. Laser powered devices are still a favorite in medical offices, which makes sense given their high cost and higher risk of adverse effects such as skin irritation.

Red light products on the market vary quite a bit in terms of their intensity (or power) and the specific wavelengths of light that they deliver. Studies vary in both parameters, and it appears that a range of wavelengths and intensity are beneficial. For maximum versatility, it is recommended to choose a multiwavelength device that provides both red and near infrared light, since each has some unique cellular effects. In terms of intensity, it may be ideal to mimic the intensity of the sun, which is around 24 mW/cm² at the skin. This is described as the “sweet spot” between higher intensities, which can have harmful effects, and lower intensities, which will have no effect at all. When using red light therapy to support the lymphatic system, choose a sun-mimicking product and don’t overdo it when it comes to treatment frequency and duration.

Red light therapy devices come in several forms, many of which can be used to support the lymphatic system. Red light LED panels can be used to treat most body parts, including the face, chest and back. Panels provide broad coverage but do require you to stay stationary and seated during the treatment. Panels are a good choice for directing light at the lymphatics in the neck and upper chest, around the thymus gland. If you would prefer to lie down while doing a treatment, you would do better with a portable LED wrap rather than an LED panel. Portable devices are also the best choice if you would like to have the option of moving around during your treatment. Portable red light wraps can comfortably be used on most body parts except the head and neck. Red light wraps that are specifically designed for the head are the best option for targeting the glymphatic system in the brain, although this system can also be supported with an LED panel. Every person’s needs are unique, but there are many different device options to choose from.  

Conclusion

Red light therapy can be used at home to support the health of the lymphatic system. Research has demonstrated that it is a safe and effective treatment for a range of disorders, such as dementia, lymphedema, and inflammation. By improving the structure and function of lymphatic vessels, red light therapy increases the flow of lymph. This may be especially important in the brain, where waste buildup can cause serious illness such as Alzheimer’s disease. Choosing the right product is easy: Select a red light panel or wrap that delivers red and near infrared light, mimics the intensity of the sun, and fits into your lifestyle. 

Dr. Genevieve Newton, DC, PhD  spent close to 20 years as a researcher and educator in the field of nutritional sciences before joining Fringe as its Scientific Director. Gen’s job is to “bring the science” that supports Fringe’s products and education. She is passionate about all things Fringe, and is a deep believer in healing body, mind and spirit using the gifts of the natural world. 

The contents in this blog; such as text, content, graphics are intended for educational purposes only. The Content is not intended to substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your healthcare provider.

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