How exactly do Red Light and Near InfraRed therapy devices help our horses? Are they as good as lasers? These are valid questions and ones that many people are asking as more and more of these boots and pads appear in the equestrian marketplace. And before we even attempt to answer that, are we even comparing like with like, when one costs a few hundred bucks and the other thousands of dollars?
In this quick run through, I sum up:
- What Red Light NIR is
- What we know
- Dosage
- Other factors
- Comparing laser with RL NIR
- A different approach?
What is known about Red Light and Near Infrared therapy for horses?
Red Light is visible and has a frequency of 620-750 nm. The optimal range within this is 630-670 nm.
Near InfraRed can’t be seen with the naked eye, as it has a frequency of around 800-2000 nm. The most effective range within this is 810 nm to 850 nm.
These wavelengths penetrate tissue to different depths. They have an effect on animal tissue through a process called Photobiomodulation (PBM), as does laser therapy.
The abundance of similar products for humans has led to more research into their effects. Despite some conflicting results, there is evidence of three effects on tissue: decreased inflammation, decreased pain, and accelerated healing.
This occurs at cellular level, with PBM stimulating production of ATP (adenosine triphosphate), nitric oxide (NO) and reactive oxygen species (ROS) – substances responsible for a cascade of effects that influence inflammation, pain, and healing.
If there’s one thing to remember, it’s this: with PBM, the mitochondria in the cells produce more energy (adenosine triphosphate or ATP). This leads to an energy boost that triggers further responses:
Increased Blood Circulation. Red and NIR light improve blood flow (vasodilation – vessels widen). This brings oxygen and essential nutrients to damaged tissues, while helping to remove waste products that contribute to inflammation and pain.
Reduced Inflammation. Inflammatory markers (cytokines) are reduced, thereby addressing the underlying cause of many chronic pain conditions – especially arthritis.
Faster Healing. With cellular metabolism and regeneration stimulated, the body’s natural healing processes accelerate, benefiting tissue repair.
Horse owners report back
Research is still emerging, so in the meantime we’re often relying on ‘anecdata’ – i.e. strong anecdotal evidence, the type that might underpin new studies – in our evaluation of benefits.
I hear regular reports of pain being alleviated, inflammation reduced, and swelling (oedema) moving in multiple cases. These include tendon and ligament injuries. More recent reports from customers include improvement in cellulitis (in horse and owner).
I’ve received a few reports of improvement around fetlock level ligaments, with reductions in shape change around the fetlock and sesamoids. These have come with frequent and usually daily use.
What about dosage?
Dose is important and yet, with so much research happening, it is hard to specify what the dose is.
Treatment dose is usually expressed as energy delivered (joules) per square centimetre (J/cm²). This is also known as fluence. Suggested doses vary, but guidelines often quote around 1–4 J/cm² for superficial tissues and 8–20 J/cm² for deeper tissues.
Although dosage calculations are often discussed in relation to a single laser probe, they can also be applied to multi-diode LED devices. The challenge with boots and pads is determining how much light is delivered across the entire treatment area.
Other variable factors are the anatomic site, tissue depth, species, coat colour and length, skin colour, and body condition score.
And then there’s patient preparation, application technique, frequency of administration, and patient management.
Dosage: how do the LED boots and pads compare with veterinary lasers?
It’s important to understand that a veterinary laser and an LED therapy boot deliver light in quite different ways.
A 10W veterinary laser operating for 15 minutes delivers 9,000J of energy. An individual 150 mW LED operating for the same time delivers 135J.
However, these figures describe the total energy produced, not the amount of energy delivered to each cm2 of tissue.
A laser concentrates its light into a relatively small area, whereas LED boots use multiple diodes to spread light over a much larger area.
For example, the tendon boots sold on this site have 110 diodes per boot, each containing two red light chips (660 nm) and one near-infrared chip (850 nm). The manufacturer’s stated power is 55W, with an irradiance of 150 mW/cm².
Irradiance simply means how much light energy is delivered to each square centimetre. Using the manufacturer’s stated figure, a 15-minute continuous treatment delivers a (theoretical) dose of 135 J/cm².
So, when comparing laser and LED devices, we need to look beyond the wattage and pay attention to:
- the number of diodes,
- the area being treated, and
- the amount of light delivered across that area.
Penetration depth is influenced by wavelength (850nm, etc) and the characteristics of the tissue being treated (its composition, pigmentation and thickness). Different wavelengths are absorbed and scattered differently as they pass through tissue.
What it does influence is the speed of application, as high power accelerates the number of photons that can achieve the maximum depth penetration, in a particular tissue, in a fixed amount of time.
This time factor makes a difference if you’re standing next to a horse holding a device in a particular spot. Likewise, it is valuable in the veterinary treatment of an acute injury or condition (or in an acupuncture session where the collated laser beam is replacing a needle insertion).
It is very hard to calculate the dosage across the full area of a red light pad or boot. However, if we are using pads and boots regularly and even daily, we don’t have the same need for a super rapid treatment.
Red Light NIR therapy – a different approach
Nobody is claiming that this approach has the same effect as laser, or red light torches for that matter.
There is increasing evidence that the broad coverage of red light and infrared diodes has a more generalised, systemic effect on a region of the body, particularly when used frequently and repeatedly.
Although the light’s penetration isn’t deep, it seems to bring about some significant changes.
- Cellular interaction: Red and near-infrared light penetrates tissue and is absorbed by chromophores, primarily cytochrome c oxidase within the mitochondria.
- Mitochondrial boost: This absorption stimulates the mitochondria, leading to increased production of adenosine triphosphate (ATP), the energy currency of the cell.
- Antioxidant and anti-inflammatory effects: The process up-regulates the body’s antioxidant defences and can decrease levels of reactive oxygen species (ROS) in stressed cells, thereby reducing inflammation.
- Modulating inflammatory response: It can activate signaling pathways to decrease inflammatory markers and promote cell survival, proliferation, and migration, which aids in tissue repair.
In this scenario, using multi-nodal devices with around 100 diodes, a lower wavelength is actually a benefit, not a deficiency.
Ready to try red light therapy on your horse? See the full range of red light and near infrared boots and pads, or save $50 with the tendon and hoof boots combo.