Phototherapy, also known as light therapy, is a form of medical treatment which applies specific wavelengths and intensities of light to a patient (10). If you Google ‘phototherapy for neuropathy’ the page floods with recommendations specifically for infrared focused light therapy. Infrared therapy is recommended for pain and muscle relief, due to circulatory and anti-inflammatory benefits that may possibly induce tissue healing (15). Ultimately, infrared light and its healing mechanisms are still not fully understood, but you may just find it to be a valuable pain reliever. Retailers, health spas, blogs, and studies provide various treatment perspectives, so understanding the methods and claims can be overwhelming. With varying information on infrared therapy available, I hope this summary makes the promising to conflicting claims less confusing.
And They Said Let There Be Light
The utilization of light therapy for preventative and therapeutic treatments has been ongoing since the 1900s (1). Niels Finsen and John Harvey Kellogg were pioneers in light therapy treatment and research. In 1903 Finsen won the Nobel Peace Prize in Medicine for his study and application of concentrated light rays, treating skin lesions from tuberculosis (11). Kellogg published Light therapeutics; a practical manual of phototherapy for the student and the practitioner (1903), which explores the healing benefits of light, from sunshine to electric light heated “baths” (7). The possibilities that different wavelengths of light afford for wound healing and pain relief continue to be studied today.
The Science Behind Infrared Therapy
Heat, whether from infrared energy or simply from a microwaveable heating pad, can do wonders for individuals experiencing pain. If you’ve ever sat in an infrared sauna, you’ve experienced the thermal effects of infrared therapy (15). Infrared therapy varies in form, with the purest thermal form being far infrared or FIR (15). The body experiences FIR wavelengths more deeply than other forms of heat (15). While a heat treatment like a microwavable heating pad may be soothing, it mainly heats a surface. In contrast, infrared energy can penetrate the skin almost 4 cm (15). With deeper tissues experiencing wavelengths, the heat dispersed is greater internally than externally, causing greater relief (15). Infrared saunas, speciality lamps, and fabrics embedded with infrared emitting nanoparticles are increasingly being promoted for these thermal effects (15).
Pure FIR energy is expensive so treatments often involve mixed versions of infrared light (15). Although FIR has the purest heating quality, other forms including mid infrared or MIR, near infrared or NIR and even LED or light emitting diodes, are explored for their non thermal healing benefits (15). This is where considering light therapy may become daunting; so many different but similar terms, wavelengths, and definitions. Pain relief, heat, and relaxation; these ideas make sense. What about infrared light independent of heat? While far infrared focused devices are obvious pain relievers for their deep heating qualities, forms of infrared light which penetrate the skin deeply, but remain cool to the touch, also exist (15). How do these non thermal effects promote healing? The mechanisms of infrared light in body cells, independent of heating, are still quite mysterious to researchers.
Non thermal focused infrared light therapy promotes the release of nitric oxide in cells, which encourages vasodilation and increases blood flow (15). This response has long term beneficial effects on body tissue, including anti-inflammatory, healing, and pain relieving properties (15). When reviewing thermal focused infrared therapy, some argue that these circulatory responses and benefits are simply a normal response to heat; infrared or not (15). However, since vasodilation occurs in non thermal infrared treatment as well, there is much more to be learned, as science develops and better understands the relationship of these processes (15). When describing the healing qualities of infrared light beyond heat, most advocates mention NASA research. Two NASA studies can be found in the public archive. One provides evidence of nitric oxide release in cells during infrared light therapy, promoting vasodilation and blood flow (13). Another feature and study notes possibilities for the future, focusing on cancer patients (5), and suggests possibilities for wound healing, pain relief, and the regeneration of muscle tissue (12). Although exciting to consider, the NASA public archives on light therapy are limited, self-noted as possibly outdated, and exist for historical record; simply something to consider when finding promises of success thanks to NASA when looking into treatments yourself. The possibilities are indeed exciting, but the studies confirm that the mechanisms of action of light on body cells is still poorly understood (13). Is lack of understanding an equivalent to lack of usefulness? The answer to this may vary based on your treatment outcome; an individual’s experience with any therapy is their own.
Many light therapy studies with regard to neuropathy are documented by the research journal Diabetes Care. Studies focus on improving feet sensation, balance, and reducing pain with different wavelengths of light. Most studies consistently return to the fact that the mechanisms of light on body cells is poorly understood, and while providing pain relief, improvements of sensation need further research and evidence. Leonard (9) et al. demonstrates small improvements in feet sensation, balance, and pain. Other studies utilizing placebo or sham therapy in contrast, such as Clifft (3) et al. and Lavery (8) et al., show no improvement to sensation. There is conflicting evidence between studies on sensation and pain, with author relationships to infrared therapy and manufacturers themselves being noteworthy. An interesting interaction includes Clifft et al. receiving and responding to study criticism from a manufacturer advocate (2). Clifft asserts, “While it is disappointing to discover that a promising new treatment may not be effective, patient treatment should be based on credible evidence. We hope that more randomized, placebo-controlled studies are conducted to either support or refute the results of our study and to help determine the rightful place of MIRE in the treatment of patients with peripheral neuropathy” (4). This perspective truly sums up the research. Much more needs to be done but it is exciting to consider the possibilities!
The Future of Light Therapy
Ultimately the precise mechanisms of infrared therapy, whether analyzed for its heat distribution or light distribution, are not understood very well. Wound healing, anti-inflammatory properties, and pain relief may be attributed to a variety of infrared wavelengths and treatment options. Therefore, how are wavelengths and their responses similar and how are they different (15)? Are specific infrared wavelengths more valuable for promoting specific benefits (15)? Are benefits a response to heat, nitric oxide release, or possibly something different like the vibrational activity of wavelengths that cause certain cell actions (15)? These are the questions developing infrared therapy research. Ultimately if infrared light therapy can be proved to have significant biological effects beyond its deep heating, then the future implications and health resources could be awesome (15).
From handheld devices to boots to lamps, there are many options in infrared light therapy. You may find infrared therapy valuable, from the deep cell science to maybe just a more effective soothing heating device. Experiment with spas or products yourself to see what works for you, knowing that infrared therapy includes many options, with varying results. Consider trying an infrared sauna and sweat out some toxins while you’re at it. Spend time speaking to your health practitioner and browsing Amazon. Note that devices may be sold and titled as a particular infrared wavelength, even if it is a mixed form (15). Read reviews. Try out products with reasonable exchange policies so that you can find what works best for you. Research is important, but beyond all the opinions and studies if you find a resource, like infrared therapy, helping you, then go for it! Health and pain management is a personal unique experience. You know yourself best.
- Barnard, Lynette. (2014). Aro – Healing Touching Lives – Theories, Techniques and Therapies. New York: Xlibris Corporation. Retrieved from: https://books.google.ca/books?id=brZNBAAAQBAJ&pg=PT414&dq=infrared+light+therapy&hl=en&sa=X&ved=0ahUKEwji29nkhZ3bAhVWHzQIHenLDMoQ6AEINTAD#v=onepage&q=infrared%20light%20therapy&f=false2.
- Burke, T.J. PHD. (2006). Response to Clifft et al. [Response to The Effect of Monochromatic Infrared Energy on Sensation in Subjects With Diabetic Peripheral Neuropathy: A Double-Blind, Placebo-Controlled Study, by Clifft, J.K., Kasser, R.J., Newton, T.S., & Bush, A.J.] Diabetes Care. 29(5):1186-1186. doi:0.2337/dc06-0040. Retrieved from: http://care.diabetesjournals.org/content/29/5/1186.1
- Clifft, J.K., Kasser, R.J., Newton, T.S., & Bush, A.J. (2005). The Effect of Monochromatic Infrared Energy on Sensation in Patients With Diabetic Peripheral Neuropathy. Diabetes Care. 28(12): 2896-2900. doi:10.2337/diacare.28.12.2896. Retrieved from: http://care.diabetesjournals.org/content/28/12/2896
- Clifft, J.K., Kasser, R.J., Newton, T.S., & Bush, A.J. (2006) Response to Burke, T.J. [Response to Burke’s Response to Clifft et al. on The Effect of Monochromatic Infrared Energy on Sensation in Subjects With Diabetic Peripheral Neuropathy: A Double-Blind, Placebo-Controlled Study] Diabetes Care. 29(5):1186-1187. doi:10.2337/dc06-0225. Retrieved from: http://care.diabetesjournals.org/content/29/5/1186.2
- Cotler, H. B. (2015). A NASA discovery has current applications in orthopaedics. Current Orthopaedic Practice, 26(1), 72–74. doi: https://dx.doi.org/10.1097%2FBCO.0000000000000196. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4272231/
- Finsen, N.R., & Sequeira, J. (1901). Phototherapy: (1) the chemical rays of light and small-pox, (2) light as a stimulant, (3) the treatment of lupus vulgaris by concentrated chemical rays. London, U: Arnold. Retrieved from: https://archive.org/details/39002010758374.med.yale.edu
- Kellogg, J.H. (1910). Light therapeutics; A practical manual of phototherapy for the student and the practitioner, with special reference to the incandescent electric-light bath. Battle Creek, MI: Good Health Publishing Company. Retrieved from: https://archive.org/details/39002011140895.med.yale.edu
- Lavery, L.A., Murdoch, D.P., Williams, J., Lavery, D.C. (2008). Does Anodyne Light Therapy Improve Peripheral Neuropathy in Diabetes? Diabetes Care. 31(2):316-321. doi:10.2337/dc07-1794. Retrieved from: http://care.diabetesjournals.org/content/31/2/316.
- Leonard D.R. MD, Farooqi H.M MD, & Myers, S. RN. (2004). Restoration of Sensation, Reduced Pain, and Improved Balance in Subjects With Diabetic Peripheral Neuropathy. Diabetes Care. 27(1): 168-172. doi:10.2337/diacare.27.1.168. Retrieved from: http://care.diabetesjournals.org/content/27/1/168.short
- Phototherapy, n.d. In OED Online. Retrieved from http://www.oed.com.elibrary.calgarypubliclibrary.com/view/Entry/235719?redirectedFrom=phototherapy+#eid
- ”Physiology or Medicine 1903 – Presentation Speech”. Nobelprize.org. Nobel Media AB 2014. Web. 17 May 2018. Retrieved from: http://www.nobelprize.org/nobel_prizes/medicine/laureates/1903/press.html
- Whelan, H.T. (2002). The Use of NASA Light-Emitting Diode Near-Infrared Technology for Biostimulation, Second International Conference on Near-Field Optical Analysis: Photodynamic Therapy and Photobiology Effects, Houston, TX. May 31-June 1, 2001. NASA/CP-2002-210786, S-896, NAS 1.55:210786. Retrieved from: https://ntrs.nasa.gov/search.jsp?R=20030001599&hterms=20030001592&qs=N%3D0%26Ntk%3DMetadata-Only%26Ntx%3Dmode%2520matchall%26Ntt%3D20030001592
- Wong-Riley, M.T., Whelan, H.T. (2002). The Effect of 670-nm Light-Emitting Diode Light on Neuronal Cultures, Second International Conference on Near-Field Optical Analysis: Photodynamic Therapy and Photobiology Effects, Houston, TX. May 31-June 1, 2001. NASA/CP-2002-210786, S-896, NAS 1.55:210786. Retrieved from: https://ntrs.nasa.gov/search.jsp?R=20030001599&hterms=20030001592&qs=N%3D0%26Ntk%3DMetadata-Only%26Ntx%3Dmode%2520matchall%26Ntt%3D20030001592
- Zinman, L.H., Ngo, M., Ng, E.T., Nwe, K.T., Gogov, S., Bril, V. (2004). Low-Intensity Laser Therapy for Painful Symptoms of Diabetic Sensorimotor Polyneuropathy. Diabetes Care. 27(4): 921-924. doi:10.2337/diacare.27.4.921. Retrieved from: http://care.diabetesjournals.org/content/27/4/921.
- Vatansever, F., & Hamblin, M. R. (2012). Far infrared radiation (FIR): its biological effects and medical applications. Photonics & Lasers in Medicine, 4, 255–266. http://doi.org/10.1515/plm-2012-0034. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3699878/
Lisa-Marie McLennan is a University of Calgary graduate, holding her Bachelor of Arts: English Literature major & Psychology minor. Also see: http://calgaryneuropathy.com/about-us/ to learn more about Lisa Marie.