Red light therapy (RLT) is a type of treatment provided in clinical and cosmetic settings that incorporates red light to improve the skin’s appearance, such as reducing fine wrinkles, scars, redness and acne.   It is also used in the medical setting to help reduce pain and increase healing in the joints, such as tendinitis, sprains/strains, and arthritis.

Red Light Therapy is also known as:

• Phototherapy
• Photodynamic therapy
• Photobiomodulation
• Low-level laser light therapy*
• Low-power laser therapy*
• Cold laser therapy*
• Biostimulation
• Photonic stimulation

*this is a misnomer, because red light therapy does not use laser energy.

Interest in red light therapy emerged decades ago when NASA conducted experiments on growing plants in space and healing injuries to astronauts.  Results of this research pointed to a connection between red light and positive, biological effects on human tissues.  This ability of light (photons) to alter biological activity in living cells is called photobiomodulation and is the means by which RLT achieves therapeutic benefit.

What is Light?

Understanding this requires some basic knowledge of how the eye works, and physics.

First of all, vision is possible only in the presence of light.  This means light must bounce off objects in your visual field and enter your eye, which then “translates” the bounced light into an image that is perceived by your brain.

But how do we perceive color?  White light is actually made up of wave energy that propagates in multiple wavelengths.  It is this difference in wavelengths, the molecular properties of all objects, and the design of the human eye’s retina that creates the perception of color. Objects that appear a certain color reflect the wavelength of just that color into your eye and absorb all other wavelengths. For example, a red shirt reflects the red wavelengths and absorbs the blue, orange and yellow wavelengths.  Altogether, these component wavelengths of white light is called the visible spectrum of the electromagnetic spectrum, which is shown here:

Electromagnetic energy exists as an electrical field with a magnetic field 90 degrees to its axis and propagates at the speed of light.  The electromagnetic spectrum is the range, in wavelengths, of electromagnetic energy existing in nature, from the very tiny wavelength gamma ray (.0001 billionth of a meter) to the very long wavelength of AM radio (100 meters).   Light is in between these extremes and is the only EM waves humans can see, between the wavelengths of about 380 to 700 nanometers (nm, billionths of a meter). 

When light passes through a crystal prism, it bends.  Since light is made up of different wavelengths, the component EM waves of white light behave differently (bend at different angles and speeds) as they enter the prism and can now be visually distinguished from one another as separate colors in a band:  red, orange, yellow, green, blue, indigo, violet.  Similarly, rainbows form when suspended rain droplets bend the sun’s light and separate it into its component colors.

RED light is the longest wavelength of visible light, while VIOLET is the shortest.  As the electromagnetic wavelength increases, the frequency (the number of times the wavelength passes a fixed point, measured in hertz – Hz) decreases, and so does the amount of energy it carries.  So, the very small wavelength/high frequency gamma and x-rays carry a lot of energy and are dangerous to tissues.  You may have heard that ultraviolet (UV) light can cause skin cancer.  This is because much of its energy is absorbed by the skin, where it does damage to cells.  Red light, being the longest wavelength of light, doesn’t have the energy level of UV and therefore does not pose danger to tissue; in fact, as we will discuss later, it has beneficial effects to tissues.

How Does Red Light Therapy Work?

Red light therapy is used to:

• Improve wound healing
• Reduce pain in joints
• Treat tendonitis
• Reduce headaches
• Reduce stretch marks
• Reduce wrinkles, fine lines and age spots
• Improve psoriasis, rosacea and eczema.
• Improve appearance of recent scars
• Improve hair growth in people
• Improve acne

It’s well established that light can initiate biological change in living organisms.  Perhaps the most well-known is photosynthesis, the series of biochemical reactions where sunlight energy catalyzes the formation of sugar (glucose molecules) in plants.  Photons from light get absorbed by tiny structures in a plant called chloroplasts, which provide the biological machinery to synthesize glucose (basically, stored energy) from inorganic carbon dioxide and water.

Another example of light effecting change in living tissue is vitamin D formation, where the pre-cursor of vitamin D is created when UVB light strikes 7-dehydrocholesterol molecules in the skin

With red light, the pathway is likely similar.  Many research studies have been conducted over the years to uncover the mechanism behind red light photobiomodulation; i.e. the nature of its therapeutic effects.  What is definitely known is that the red light wavelength (in the 660-700 nm wavelength range) tends to get absorbed in the nucleus and mitochondria of cells, in locations called chromophores.  Mitochondria (image below) are the structures where energy is generated for the cell, much like the previously mentioned chloroplasts in plant cells.  The nucleus contains the DNA, which is the template for protein synthesis.

We also know that photons can “excite” electrons – the tiny charges that orbit atomic nuclei.  Cells and all their parts including the mitochondria are of course made up atoms.  An “excited” electron means a movement of an electron to a higher energy orbit (further from/ less attracted to the nucleus).

In short, red light stimulation increases the energy state of electrons in sick tissues, enabling faster/enhanced reaction between adjacent molecules, as electron interactions between atoms are the basis of all biochemical reactions.  This may translate into the cell “speeding up” its activities, particularly respiration (ATP formation from glucose via the Krebs cycle, i.e. energy production) as well as waste elimination and gas exchange.  Redox signaling is the term used to describe this activity, and is the leading hypothesis for the mechanism of red light photobiomodulation.

With enhanced cellular signaling:

• If the cell is a fibroblast, it could lead to faster wound healing, as fibroblasts migrate to the injury/damaged site to synthesize and lay down collagen fibers.
• If the cell is a stem cell (undifferentiated cell), it could enhance the transformation of stem cells to fibroblasts or chondrocytes, which make collagen and cartilage, respectively.
• If the cell is an epidermal cell, it could mean faster cell turnover to clear out abnormal cells in skin conditions such as eczema and psoriasis.

Cells are programmed to respond to specific extracellular signal molecules for development, tissue repair, immunity, and homeostasis.  Errors in signaling interactions may lead to diseases such as cancer, autoimmunity (such as rheumatoid arthritis), and diabetes.  Given this, it is feasible to assume that if red light therapy can enhance cell signaling, it can benefit these cellular functions and support tissue healing and pain reduction.

Red Light Therapy is Shown to Reduce Inflammation

Many studies found that red light reduced inflammation in tissues.  Inflammation is the body’s response to injury or some kind of irritant and is characterized by redness, swelling, and pain.  It involves a complex series of steps involving multiple protein clotting factors in the blood and tissues.

Inflammation also involves several types of cells involved in the reparative process, including macrophages (“cleaner” cells that remove debris), basophils (a type of white blood cell that secretes histamine and heparin to make blood vessels more leaky and manage clotting), and fibroblasts.  It also involves cytokines—chemical signaling molecules that cells use to communicate and coordinate activities within themselves and with each other.

Inflammation often gets out of hand at the injury/ damaged tissue site and contributes to the problem by increasing pain and delaying healing.  In fact, diseases like arthritis, irritable bowel syndrome, vascular disease, diabetes, and even Alzheimer’s disease involve chronic (ongoing) inflammation.  This is the basis for the utilization of anti-inflammatory medications such as steroids and non-steroidal medications (NSAIDs) like Tylenol and Ibuprofen for inflammation.

The inflammation-reducing ability of red light therapy is likely due to its ability to enhance cell signaling and molecular flow in the cell.  One study notes that overall reduction in inflammation is one of the most reproducible effects of photobiomodulation [from red light]. This is particularly important for inflammatory diseases affecting joints; acute trauma, lung disorders, and brain injuries resulting in inflammation.

Another proposed model to explain how light therapy works is photon-mediated ion channels in cell membranes (image below).  Basically, ion channels are the passageways in membranes (think tiny gated doors) where ions flow through, which require energy to open.  An electrical gradient is formed as the ion concentration differs on either side of the membrane, and this gradient can be used to drive movement of molecules into and out of the cell, very much like voltage.  In fact, this is how neurons produce nerve impulses.  Red light photons may be able to activate these ion channels, thereby boosting efficiency of ion flow and helping the cell maintain equilibrium.

Should You Try Red Light Therapy for Arthritis?

Given its photobiomodulation ability, red light can be a useful, self-administered treatment for skin conditions and tissue injury/pain.  It has powerful effects of improving cellular function to diseased/ injured tissues, which can improve recovery and healing.  Being lower frequency, it is not harmful to the body, unlike UV light.

However, red light therapy should not be considered a “magic bullet” for “curing” things.  Every person is different, and if you have complicating factors in your health and/or your condition is advanced, it may not work as well.  While the human body has remarkable regenerative and healing abilities, there are limitations.

For example, in the case of advanced degenerative osteoarthritis of the knee or hip, much of the cartilage has worn away, and there are multiple areas of exposed bone.  Normal, healthy cartilage that lines joint surfaces is smooth and resilient to pressure.  Unlike the epidermis (skin), it does not regenerate very well, so if you lose quite a bit of it or tear it, it cannot regrow back to normal.

But, if you are at the very early stages of osteoarthritis, red light therapy can be very helpful in arresting its progression.  Arthritis usually appears mid-age, but if you engaged in heavy contact or heavy impact sports such as football and gymnastics, it may start earlier.  What happens is tiny disruptions in the cartilage start to gradually separate, much like how a tiny crack in your windshield “grows” in length as your car absorbs shock from the road each time you drive.  These tiny separations then form pits in the cartilage, which widen. Bone is exposed, inflammation sets in, and you’re on your way to an eventual knee or hip replacement some years later.  But if you apply red light therapy to the tiny disruptions as they form, there is a much better chance of arresting their progression by stimulating cartilage growth.  The red light will energize chondrocytes, the dormant cells embedded in the cartilage matrix tasked with maintaining it, and can stimulate the proliferation of chondroblasts, the cells that secrete collagen matrix.

You can still apply red light to an advanced osteoarthritic knee for palliative purposes, since red light can suppress inflammation and therefore provide some degree of pain relief.  If doing so allows you to stay on your feet a couple more hours in a day, then that is definitely a positive benefit to your quality of life.

A good solution for applying red light therapy to the knee is the 120 LED wrap.  It is a flexible pad containing 120 light emitting diodes (LEDs) with each diode containing one (1) 660 nm red light emitter and two (2) 850 nm infrared emitters.  You wrap it around your knee and hold it in place with an elastic band that comes with it, and press a button.

Alternatively, if you are patient, you can use a red light torch device.  This requires you to hold it in place for a couple of minutes.  The good thing about the torch is that you can target small areas.  For example, if you know you have a cartilage tear on the inside of your knee joint, you can press the torch over it and concentrate the light on that one spot.  The torch is also good for small joints; i.e. knuckles.

As always, when you self-treat conditions use a multi-pronged approach:  improve your diet, get enough rest, drink enough water every day (sometimes not easy to remember!), avoid ingesting toxins as best you can (nix smoking, alcohol, processed food, excessive pollution); get fresh, clean air by walking where there are lots of trees; exercise/ move often to strengthen your muscles and heart, and avoid negative thinking, which elevates stress hormones.  Do all these things consistently and you can rest assured that you are giving your body its best chances for recovering from disease and pain.

When I talk about the nature of joint aches and pain such as hip pain, knee pain and shoulder pain, I explain that the human body is basically a biological (living) machine.  Like a machine, it has moving parts comprised of levers connected by some kind of mechanism that redirects force.  Think car engines, certain power tools and watches.

In the human musculoskeletal system, those levers are the long bones such as the femur and ulna, and the connecting mechanism/ force redirectors are the joints.  Like a machine’s mechanical components, joints will gradually wear out with use.  The more hours/years of use, the more likelihood of breakdown.  Think football players and those in heavy labor jobs.

When a moving part of a machine gets prematurely damaged from an accident like dropping or overloading, it gets repaired—a replacement part is installed and/or a mechanic puts things back together and makes necessary adjustments.  However, the machine is never the same.   The accident typically causes moving components to misalign ever so slightly, which results in more friction and accelerated wear and tear, leading to impaired efficiency and eventual breakdown again.

Similarly, if you twist and injure your knee, hip or other joint and get it repaired surgically, or by a chiropractor or physical therapy/ rehabilitation it is never quite the same—most people will lose some degree of functionality because the natural alignment has been permanently altered.  You may lose a few degrees of arc of motion; hear some clicking sounds with movement (called crepitus), and lose some strength in the affected joint.  Worst case, you will experience chronic pain.

Your joint health obviously plays a huge role in your quality of life.  The good things in life involve movement, which depends on joint function.  Your joints must be able to first of all exist without pain.  They must be able to move your body in the manner you wish to move, without mechanical limitations.  And, they must be able to withstand forces while they move your body parts– jumping, climbing, lifting, carrying, etc.  That’s the best case scenario.

But what if you are one of the millions of people who have some form of joint pain; either from wear and tear, or from an accident such as a sports injury, work injury, fall, or car accident?  These things happen to almost everyone at some point.

It depends first of all on how bad it is.  How much structural damage occurred will determine the extent to which your joint can be rehabilitated/ returned to normal.

Unfortunately, the tissues that comprise joints are of the type that do not regenerate very well.  This includes tendons, ligaments, cartilage and muscle.  As I wrote before, tendons, ligaments and cartilage are classified as connective tissue, which does not contain many living cells, per unit mass.  They are mostly protein filaments (collagen, elastin) embedded in a special matrix whose main function is structural.  The few cells found in connective tissue are mostly dormant (chondrocytes, fibrocytes) and can effect minor repairs and maintenance:  tiny tears of collagen can be repaired, but large tears cannot.  Tears/injury to cartilage, such as a meniscal tear or rotator cuff tear, are either repaired by surgical reattachment, or left alone to become chronic leaving the individual with a certain percent loss of function.

Compare this to skin tissue, classified as epithelial tissue, which can heal relatively fast due to the high density of cells (they divide in number to create new tissue) and blood supply.  Think of the last time you got a cut– how relatively fast it healed, and is no longer noticeable.

So if you are fortunate to not have joint pain, think proactively now to keep it that way.

If you are experiencing any level of joint pain and/or dysfunction, learn things that you can do to reclaim some of that function AND slow down the progression, which is what I can help you with.  Even chronic cases of joint pain can be improved, so don’t give up hope.  You may not be able to make the pain go away entirely, but if you can reduce the severity of your pain by 50% and/or increase range of motion by a couple of degrees, that can translate into a dramatic improvement in your quality of life.

The Two Main Approaches to Maintaining Joint Health

Let’s review the main joints involved in everyday movement patterns.

First of all, the weight bearing joints of the lower extremities:  hips, knees, ankles, foot joints.  We can also include the lumbar spine (low back).  These joints have the dual task of bearing the body’s weight (and more than your weight if you do high impact activities) while allowing ambulation—running, walking, climbing, etc. and are therefore larger in terms of surface area contact and number of ligaments.

Secondly, the non-weight bearing joints of the upper extremities:  shoulder complex, elbows, wrists, and hands.  While they don’t bear as much weight as the hips, knees, ankles and feet, these joints are involved in anything you do with your arms/ hands.  They are smaller and generally have more moving parts, so these joints are vulnerable to degeneration as well, especially the glenohumeral joint of the shoulder.

The first course of action in preventing joint degeneration, which tends to start in most people around age of 40, is through diet and nutrition.  Eat a wholesome diet rich in phytonutrients; i.e. plants.  Phytonutrients are vitamins and minerals naturally found in plants that are important co-factors in numerous biological functions, such as enzymatic activity, tissue repair and anti-inflammation.  Some like turmeric are strong anti-oxidants.  Think of oxidation, or oxidative stress, as the body’s version of rust.  Oxidation is what causes rust and decay in metals; oxidation in the human body damages cell membranes, proteins and DNA.  It is caused by excess free radicals— oxygen-containing molecules that have an unpaired electron, making them highly reactive.  They take electrons from tissues in order to return to a stable state, which damages them.  In fact, oxidative stress is a leading theory of aging and joint wear and tear.  Eating a diet rich in phytonutrients—green, leafy plants and plants with hues of blue, purple, and orange equips your body with the nutrients it needs to counteract oxidative stress.  Thus, think of a plant-based diet as being protective of your joints.

On the contrary, eating a diet rich in processed foods and added sugar can place a burden on your body.  Not only is there a lack of nutrients, there are ingredients that can raise your triglycerides and bad cholesterol; form plaque in your arteries, and even cause toxicity.  They must also put a strain on your liver, lymph system and kidneys, the organs involved in detoxifying your body.

Next, move those joints!  You’ve got to find the right balance between helpful movement that exercises and strengthens your joints, and the ones that can cause damage.  I’m not saying to avoid things like weight lifting and running, because when done properly, they benefit your joints.

Basically, repetitive jumping activities and wrong running technique that “pounds” your knees, hips, feet and spine joints have the potential to cause tiny cracks in your cartilage, which can expand into pits and eventually tears.  An example of the movement you should avoid is playing basketball often, where you run on a hard court and jump and land hard to do layups numerous times; often landing on one leg first.

Running is a great aerobic exercise, and I do it myself, being in my mid-50s.  But do it wrong, and you are setting yourself up for hip, knee and foot pain.  With running, first of all, I highly advise running no more than 20 miles a week.  You don’t need that much cardio from running, and running beyond this point every week turns the tables, as the cardio benefit is at the expense of your hip, knee and feet joints.  Long distance running is especially not advisable, as it can generate excessive free radicals, causing oxidative damage to your body. Repetitive pounding especially if you are over the age of 40 when cartilage loses its thickness and pliability can cause micro-tears which can expand as you keep doing it, like a tiny, 2mm crack in a car windshield that gradually grows into a really big crack with every bump in the road.

Also with running, definitely do not use a jumping type movement.  Think more in terms of really fast walking.  Keep your feet close to the ground as you run, and land on the forward half of your foot (toes, ball and arch) rather than your heel.  Your head should not bob up and down as you run; or it should be minimal.

Do closed kinetic chain exercises.  This means the levers involved in movement (i.e. for lower extrmities, your lower leg and foot) are secured to the ground during force generation.  A perfect example are squats and lunges.  With this type of exercise, you have more control, and you isolate the muscle better because your leg is secured to the ground with your weight.

For upper extremities, an example is planks and push ups.  Chin ups as well — same concept, the levers are firmly secured as you exercise the muscles and joints in a controlled fashion.

Remember, joints are comprised of two bones connected by ligaments.  A tendon (the ends of a skeletal muscle) crosses over the joint and connects somewhere on both bones (origin and insertion points).  So when you do squats, you are strengthening the ligaments and tendons of the joint, giving it more support.  With more support, the joint is more stable and able to withstand forces better; i.e. it will last longer.  How does it happen?  Wolf’s Law of physiology states that connective tissue increases in mass in response to repeated loads.  It’s one of the body’s many survival and environmental adaptation mechanisms.  The mechanical stress signals to the brain to mobilize cells to secrete more matrix and collagen to handle the load.  This is why resistance exercises are highly recommended for women who are at risk for osteoporosis—it builds up bone mass and turns down bone loss.

Conversely, being sedentary leads to muscle, bone, and connective tissue atrophy.  Weak joint components will increase your risk of injury.

But again, be careful not to overdo it.  Do the movements slowly and controlled, and focus your mind on controlling the primary mover muscles rather than your rep goal.  This will maximize joint strengthening and minimize injury.

Summary of Main Points

1. Proper joint function is necessary for everyday movements, and therefore is critical to quality of life.
2. Joints are prone to injury and degradation due to their daily use.
3. It is advisable to be proactive to ensure your joints stay healthy throughout your life because joint components are comprised of tissues that do not regenerate well.  One major injury can mean lifetime dysfunction.
4. The recommended approaches to maintaining joint health are a plant-based diet rich in phytonutrients, and closed kinetic chain exercises to strengthen your joints so that they are more durable and resistant to injury and degeneration.

Next time, I will discuss more ways to keep your joints healthy, and if you already have chronic joint issues, things you can do to reclaim function.