How Red Light Therapy Differs from Near Infrared Light Therapy, and What is Low Level Laser Therapy?
Light therapy terminology could be bewildering. The only way around this is to understand this terminology, the meaning behind the terms and the types of light therapy. If you are new to the light therapy space, you may find this cascade of names overwhelming and confusing. Hopefully, this article will help you to bring some order and clarity on the subject of light therapy related terminology.
Red light therapy and low-level laser therapy (LLL) are terms that describe the use of light in therapeutic applications. These terms are better known, because they have been around longer than other terms denoting light therapy. For example, near infrared light therapy (NIR) and infrared light therapy (ILT) are also two forms of light therapy. Their names are defined by the spectrum of the wavelength used. Each of them, as well as the red light therapy, can be a form of LLL. Another term for light therapy, that is more recent, is photobiomodulation therapy, PBM or PBMT.
Understanding the differences among various forms of light therapy is not as complicated as it might seem at first. The easiest way to start is to understand the related terminology. To do that, you should start from the top of the hierarchy and move down the chain. Along the way you will be able to learn and understand the relevant terms.
The Hierarchy of the Light Therapy Terminology
The term light therapy is the original name. Therefore, it stands at the top of the hierarchy. More modern equivalent of light therapy is photobiomodulation therapy (PBMT). Thus, these two terms are equal in meaning and occupy the top position in the hierarchy. The next level deeper brings about terms that are critical in understanding of the variety of forms of light therapy.
Already mentioned earlier, low-level laser therapy, is one of the earliest modern forms of light therapy. Originally developed in the 60s, this name became equivalent to the name light therapy. They are often used interchangeably. However, this is not a completely correct way to use these terms. While LLL is a form of light therapy, it is not its only form. Furthermore, LLL usually refers to light therapy in the red light thorough to infrared wavelength spectrum. Yet, today, there are numerous other light therapy options from yellow to blue to ultraviolet light spectra.
This article will focus only on the subjects relevant to the light therapy in the red to infrared spectra. This should help to avoid any confusion regarding beneficial effects of light. Thus, unlike the light in red to infrared spectra, light of other spectra could be harmful in some cases. For example, ultraviolet light can cause harm, if it is used improperly. However, that is the subject matter which outside of the scope of this article.
LLL and LED Light Therapy Options
Since the invention of LLL, technological advancements allowed the use of modern light emitting diodes (LED) for light therapy. Thus, LEDs dethroned low level lasers (LLL) as the only option for light therapy. Nonetheless, many are still using the term LLL synonymously with light therapy. Just like the brand name “Hoover” displaced the common name “vacuum cleaner” for many, “LLL” displaced “light therapy” for some. However, regardless of individual preferences for terminology, the reality is that today LLLs and LEDs share the light therapy space. Each one is prominent in its own rights and for numerous applications in general wellness, medicine and beauty related fields.
The Top Levels of Light Therapy Terminology
To sum up, the two top levels of the light therapy hierarchy are:
Level 1: Light Therapy or Photobiomodulation (PBM)
Level 2: Low level laser (LLL) therapy and LED-based light therapy.
The next level down brings about terms that differentiate forms of photobiomodulation by the wavelength of light. Thus, you may encounter terms like red light therapy, near infrared light therapy and infrared light therapy. While these three types of photobiomodulation closely related, they also differ.
Prior to discussing these three wavelength options, it is important to note again that there are others. For example, ultraviolet light, blue light, green light, they all have their uses. They differ in wavelength and the quality of light. However, most importantly, they differ in the effects of these types of light on the body.
As you may recall, the focus of this article is on the light in the red to infrared spectra. Therefore, there will be no discussion of any light in the other spectra. You will be ahead of the game, if you remember that the applications of those forms of light are different.
Photobiomodulation using Light in the Red to Infrared Spectra
The red light waves fall in the range of 600 nm to 700 nm. The near infrared light waves fall into the 700 nm to 1400 nm range. The term “near infrared” alludes to the fact that this is the type of invisible infrared light that is closest to the visible red light range. Last, but not least, is the infrared light, which falls into the 780 nm to 1 mm wavelength spectrum. These three types of light have different depths of penetration and absorption by the life tissue. Therefore, their applications are in accordance with those factors.
Thus, to sum up, the next level in the terminology hierarchy belongs to the wavelengths of the light. The focus of this article is primarily on red to infrared light spectra. Other wavelengths of light, from yellow to blue, are also suitable for various forms of light therapy applications.
Level 3: Photobiomodulation based on the light wavelength, or spectrum:
- Red light therapy.
- Near infrared light therapy.
- Infrared light therapy.
Types of Photobiomodulation by Application
Now you can differentiate three levels in defining light therapy or PBM. Moving forward, the next level in the hierarchy of terminology defines PBM by application type. Thus, red light therapy is suitable for topical and systemic applications. It can be used for wound healing, for various forms of skin therapy, for muscle relaxation and more. Numerous studies provide evidence to support benefits for these applications.
The term systemic photobiomodulation defines applications of red light therapy via the blood. Relatively recent research has shown that blood contains free-floating mitochondria, which absorbs the energy of red light. The term systemic implies that this type of light therapy can produce systemic effects in the body.
Using Light Therapy for Brain Stimulation
Perhaps the most complex and sophisticated application of light therapy is its use for brain stimulation. This form of light therapy is called transcranial photobiomodulation or tPBM. The light is used to penetrate through the skin, muscles and the cranium to reach the brain. Current research shows that the best form of light for tPBM is near infrared light (NIR). NIR has presented best penetration and absorption rates, and these facts have been documented using EEG and MRI scans of the brain.