Over the past several months, I have been writing about novel therapies marketed to athletes to improve recovery from injury. In this article, we will consider a treatment relative to something I wrote about recently, low-level laser therapy (LLLT) that is advocated more as a recovery tool than for helping with injuries.
As you may recall, LLLT leverages photobiomodulation to affect the body’s tissues. The theory behind this is that when the light of specific wavelengths penetrates the tissues, it causes changes within the cells to produce a result. In the case of LLLT, research demonstrated those results were at best modest, with evidence only to support its use for chronic Achilles tendinopathy.
While LLLT utilizes light of a short wavelength, red light therapy uses visible light with a much longer wavelength and is suggested to have very different effects. Several LED red light panels manufacturers claim that their use can impact everything from sleep quality to skin appearance to sexual function to athletic performance and more.
These panels are quite costly, ranging anywhere from hundreds to thousands of dollars, so the discerning athlete would be wise to wonder whether this is an investment that can be expected to pay off with any of the promised benefits.
Red Light Therapy Basics
The theory underpinning how red light therapy works is similar to LLLT. With red light therapy, longer wavelength visible and near-infrared light is applied to the skin. Upon penetrating the cells, mitochondria absorb it and have their function modified to produce more ATP, the energy molecule for the cell’s functions. This is hypothesized to improve performance and endurance sooner after hard workouts than without it.
The evidence to support most of the claims made by manufacturers of red light therapy devices is either very scarce or weak or both. However, there is a fairly robust amount of evidence on the use of this modality for exercise performance. A review article from 2016 summarized much of this evidence.[i]
The first group of studies evaluated red light therapy to improve performance or recovery after hard efforts when applied to the upper extremities. Studies evaluated both objective markers of performance and biochemical markers of cellular damage and subjective reports of muscle soreness. While some studies in this group reported improvements in biochemical markers of cellular damage with red light therapy, this finding was not associated with any objective measures of improved performance nor any reported improvements in delayed onset muscle soreness (DOMS). A single study in this group of 10 reported a slight performance improvement.
In another group of studies evaluating red light therapy applied to the lower extremities, the results were very inconsistent, with some studies finding improvements in performance and others not. Similarly, there was varying reporting of improvements in subjective reports of discomfort associated with DOMS and no findings to suggest any changes in biochemical markers of cellular damage in these athletes.
A final group of studies sought to determine if red light therapy might have longer-lasting effects on cellular functions. In these papers, researchers reported on experiments designed to evaluate if red light therapy could change cellular functions over time in a way that would benefit an athlete by leading to improvements in muscle tissue architecture and the ability to handle oxidative stress.
The theory is that longer-term exposure to red light therapy might upregulate the expression of specific genetic pathways altering both characteristics. Once again, the results were very inconsistent. Some studies did report changes in muscle architecture over time, but those changes were not associated with any performance benefits. No studies found any improvements in the ability of tissues to handle oxidative stresses.
Current Red Light Therapy Conclusion
It would appear that based on what is known about photobiomodulation and specifically red light therapy at this juncture, it remains an interesting yet very much unproven technology. While there is clearly the ability to mass-produce and market these devices, the evidence to support their use remains lacking.
This is another example of a technology with significant theoretical benefits but no proven clinical benefits to date. That may change as additional studies are done, new applications are developed, or the technology is modified somehow. Still, red light therapy remains a novelty for now and is not worth the significant investment.
Train hard, train healthy.
[i] Ferraresi C, Huang YY, Hamblin MR. Photobiomodulation in human muscle tissue: an advantage in sports performance? J Biophotonics. 2016;9(11-12):1273-1299. doi:10.1002/jbio.201600176
