[This is a guest blog by Liam Sutton. Liam is a senior at Ball State University working towards his bachelor’s degree in exercise science with a concentration in basic and applied sciences. He hopes to attend Australian National University’s Master of Neuroscience program after graduation. He is currently participating in the Athletic Lab Internship Program.]

“The Armoury” from Red Light Rising in the Athletic Lab Recovery room.

In the Athletic Lab recovery room, athletes have access to a red light therapy apparatus. This blog post is intended to educate Athletic Lab athletes on what red light therapy is, why an athlete would use it, and how to utilize it for optimal results. 

What is Red Light Therapy? 

Red light therapy is a form of light therapy that uses red and/or near infrared light to stimulate cellular energy production. While we can see red light, infrared light is outside the visible spectrum, meaning our eyes cannot pick it up. Our inability to see it does not lessen its effects; however, as both red and infrared light have been shown to have a variety of positive effects on the human body which can be harnessed to improve athletic performance and recovery. Research has shown improvements in sleep and many aspects of sport performance. Some literature suggests faster recovery from training. This article will address each of these elements, as well as look into what we think is the primary underlying mechanism of red light therapy so athletes who are interested will have a better understanding of what is happening at the cellular level. We will begin by going over how red light therapy can influence a state we spend about a third of our lives in — sleep. 

Red Light and Sleep

Sleep is arguably the most important mode of recovery from physical activity. During sleep, the body works to restore all the systems that are taxed during waking hours.  These include immune, endocrine, nervous, and musculoskeletal systems. Proper restoration and adaptation of these systems is absolutely vital to performance development in athletes. Not all sleep is created equal; to be effective, sleep must be of adequate quality, duration, and timed in alignment with your circadian rhythm (Doherty, 2021). One of the best known tools to improve sleep quality is exercise. Research has shown that consistent exercise is associated with better sleep (Youngstedt, 2005). However, there are some cases in which exercise can negatively impact sleep quality.  Sleep quality has been shown to be negatively affected by exercise directly before bed (van Straten, 2009). In addition, poor-quality sleep is a known indicator of overtraining syndrome. This is when an athlete trains excessively, leading to an inability for the body’s recovery to match its demands, decreasing performance returns. Good sleep quality can be an important tool to help an athlete prevent overtraining syndrome during periods of high intensity training (Roose, 2009). How can we ensure that our athletes are getting proper sleep and recovering from intense training sessions? A study on a group of Chinese female basketball players (Zhao, 2012) set out to test the effects of red light therapy on sleep quality and serum melatonin levels. It was found that, when compared to a placebo group, the group receiving red light therapy experienced better quality sleep and increased melatonin secretion during the night. This study is a promising indicator that athletes using red light, especially in the evening before bed, will have better quality sleep; therefore recovering better from intense training sessions. Another issue facing athletes who practice early in the morning is the phenomenon of sleep inertia. Sleep inertia is that groggy feeling you experience after waking up. It has been shown to impact short-term memory, alertness, and overall performance (Hofer-Tinguely, 2005). Researchers (Figueiro, 2019) have shown that using red light during or just after waking can help to mitigate sleep inertia leading to increased alertness and performance. Now that we understand how athletes can use red light for sleep and what benefits they can expect to receive, we will go into its applications for sports performance and recovery.  

Red Light and Performance

Perhaps the most logical question an athlete may ask when confronted with a relatively new or unfamiliar form of therapy is: “Will it improve my performance or recovery?” The odds with respect to red light therapy are promising, but slightly mixed. Research has demonstrated some very exciting benefits in enhancing athletic performance, including significantly higher strength increases when compared to a control group (Ferraresi, 2011), endurance increases three times faster than a control group (Miranda, 2018), and increased fatigue resistance during a max repetition test when applied during rest intervals (de Brito Vieira, 2014). The next logical question an athlete might ask would be: “What is the best time to use red/infrared light to get the most out of it?” According to a 2016 paper, the application of red and infrared light yielded enhanced strength gains when applied before strength training (Vanin, 2016). For endurance athletes, light applied both before and after training led to the threefold increase in endurance improvement seen in the Miranda aforementioned study. If strength is your goal, red light should be used before your session. Endurance athletes can expect maximum returns when using red light before and after training. The red light apparatus housed at the Athletic Lab has a maximum time allowance of 20 minutes, which is considered to be the point of diminishing returns. When using red light, as you move closer to the source, deeper tissue penetration occurs, and less time is needed to receive beneficial effects. We will now look at whether or not red light therapy has any uses in tissue recovery from training.  

Red Light and Tissue Recovery

The effects of red and infrared light on tissue recovery are somewhat conflicting. Delayed onset muscle soreness (DOMS) is the feeling of soreness and inflammation caused by damage to muscle tissue during training. While DOMS typically doesn’t last for more than a few days post-training, it does lead to performance decrements in the period it is present. This is why coaches will typically program weight room sessions with less frequency and intensity during in-season training, so as to avoid negatively affecting competition performance. Naturally, researchers set out to determine if red and infrared light had any significant effects on DOMS. One such study (Baroni, 2010) found that using light therapy before an eccentric bout of exercise reduced the negative effects of muscle damage on muscle function. This is noteworthy because we know that eccentric exercise will typically have the strongest DOMS response when compared to the other contraction types. While this is promising, a systematic review (Nampo, 2016) involving 15 studies and 317 participants determined that the evidence for significant DOMS reduction from red light therapy is lacking and gave the opinion that more and better research will be needed to form a definitive scientific consensus. The next section will summarize what we know of the primary mechanism of red light therapy for those interested. 

Mechanism of Red Light Therapy

In this section, I will attempt to simplify the primary way in which red and infrared light act on our cells. The intentional use of different wavelengths of light to provoke activity at a cellular level is referred to as photobiomodulation (PBM) or sometimes low-level laser therapy (LLLT). The primary affected site by red/near-infrared light (NIR) is the last member of the electron transport chain (ETC), cytochrome c oxidase (Cox) (Karu, 2005). Think of the electron transport chain as a conveyor belt of four enzyme complexes, each with a different task, located on the inner membrane of everyone’s favorite cellular powerhouse­ — the mitochondria. The job of the electron transport chain is to undergo oxidative phosphorylation, which is a method the body uses to produce large amounts of energy in the form of ATP. One vital step of this pathway requires oxygen from respiration to bind to Cox; however, oxygen competes with nitric oxide over the binding sites on Cox. Nitric oxide acts as an inhibitor for Cox, telling the enzyme to stop its work, resulting in less energy production for our cells (Brown, 2001). This is where red/NIR light comes in, photons from the red/NIR light reach the inner mitochondrial membrane, where Cox is located, and force nitric oxide to unbind from Cox in a process called photodissociation. The now free binding sites on Cox are immediately flooded with oxygen, allowing oxidative phosphorylation to resume and cellular energy levels to elevate (de Freitas, 2016). This surplus of energy in the form of ATP could be what is responsible for the benefits discussed earlier, but more research is needed to draw definitive conclusions.   

Conclusion 

The use of red and infrared light is a well-researched method of therapy with many beneficial effects for athletes. When used intelligently, an athlete can reap rewards in sleep, performance, and potentially enhance soft tissue recovery. More research is needed, but what we know points towards the conclusion that properly using red light therapy can lead to significant athletic outcomes in a shorter timeframe than training alone.   

References

  • van Straten, A., & Cuijpers, P. (2009). Self-help therapy for insomnia: a meta-analysis. Sleep  medicine reviews, 13(1), 61–71. https://doi.org/10.1016/j.smrv.2008.04.006 
  • Youngstedt S. D. (2005). Effects of exercise on sleep. Clinics in sports medicine, 24(2), 355–xi.  https://doi.org/10.1016/j.csm.2004.12.003 
  • Doherty, R., Madigan, S. M., Nevill, A., Warrington, G., & Ellis, J. G. (2021). The Sleep and  Recovery Practices of Athletes. Nutrients, 13(4), 1330. https://doi.org/10.3390/nu13041330 
  • de Freitas, L. F., & Hamblin, M. R. (2016). Proposed Mechanisms of Photobiomodulation or  Low-Level Light Therapy. IEEE journal of selected topics in quantum electronics: a publication of the IEEE Lasers and Electro-optics Society, 22(3), 7000417. https://doi.org/10.1109/JSTQE.2016.2561201 
  • Karu, T. I., & Kolyakov, S. F. (2005). Exact action spectra for cellular responses relevant to   phototherapy. Photomedicine and laser surgery, 23(4), 355–361. https://doi.org/10.1089/pho.2005.23.355 
  • Brown G. C. (2001). Regulation of mitochondrial respiration by nitric oxide inhibition of  cytochrome c oxidase. Biochimica et biophysica acta, 1504(1), 46–57. https://doi.org/10.1016/s0005-2728(00)00238-3 
  • Zhao, J., Tian, Y., Nie, J., Xu, J., & Liu, D. (2012). Red light and the sleep quality and endurance performance of Chinese female basketball players. Journal of athletic training, 47(6), 673–678. https://doi.org/10.4085/1062-6050-47.6.08 
  •  Roose, J., de Vries, W. R., Schmikli, S. L., Backx, F. J., & van Doornen, L. J. (2009). Evaluation and opportunities in overtraining approaches. Research quarterly for exercise and sport, 80(4), 756–764. https://doi.org/10.1080/02701367.2009.10599617 
  • Hofer-Tinguely, G., Achermann, P., Landolt, H. P., Regel, S. J., Rétey, J. V., Dürr, R., Borbély, A.  A., & Gottselig, J. M. (2005). Sleep inertia: performance changes after sleep, rest and active waking. Brain research. Cognitive brain research, 22(3), 323–331. https://doi.org/10.1016/j.cogbrainres.2004.09.013 
  • Figueiro, M. G., Sahin, L., Roohan, C., Kalsher, M., Plitnick, B., & Rea, M. S. (2019). Effects of red  light on sleep inertia. Nature and science of sleep, 11, 45–57.  https://doi.org/10.2147/NSS.S195563 
  • Ferraresi, C., de Brito Oliveira, T., de Oliveira Zafalon, L., de Menezes Reiff, R. B.,  Baldissera, V., de Andrade Perez, S. E., Matheucci Júnior, E., & Parizotto, N. A. (2011). Effects of low level laser therapy (808 nm) on physical strength training in humans. Lasers in medical science, 26(3), 349–358. https://doi.org/10.1007/s10103-010-0855-0 
  • Miranda, E. F., Tomazoni, S. S., de Paiva, P., Pinto, H. D., Smith, D., Santos, L. A., de Tarso  Camillo de Carvalho, P., & Leal-Junior, E. (2018). When is the best moment to apply photobiomodulation therapy (PBMT) when associated to a treadmill endurance-training program? A randomized, triple-blinded, placebo-controlled clinical trial. Lasers in medical science, 33(4), 719–727. https://doi.org/10.1007/s10103-017-2396-2 
  • de Brito Vieira, W. H., Bezerra, R. M., Queiroz, R. A., Maciel, N. F., Parizotto, N. A., &  Ferraresi, C. (2014). Use of low-level laser therapy (808 nm) to muscle fatigue resistance: a randomized double-blind crossover trial. Photomedicine and laser surgery, 32(12), 678–685. https://doi.org/10.1089/pho.2014.3812 
  • Vanin, A. A., Miranda, E. F., Machado, C. S., de Paiva, P. R., Albuquerque-Pontes, G. M.,  Casalechi, H. L., de Tarso Camillo de Carvalho, P., & Leal-Junior, E. C. (2016). What is the best moment to apply phototherapy when associated to a strength training program? A randomized, double-blinded, placebo-controlled trial : Phototherapy in association to strength training. Lasers in medical science, 31(8), 1555–1564. https://doi.org/10.1007/s10103-016-2015-7 
  • Baroni, B. M., Leal Junior, E. C., De Marchi, T., Lopes, A. L., Salvador, M., & Vaz, M. A.  (2010). Low level laser therapy before eccentric exercise reduces muscle damage markers in humans. European journal of applied physiology, 110(4), 789–796. https://doi.org/10.1007/s00421-010-1562-z 
  • Nampo, F. K., Cavalheri, V., Ramos, S., & Camargo, E. A. (2016). Effect of low-level  phototherapy on delayed onset muscle soreness: a systematic review and meta-analysis. Lasers in medical science, 31(1), 165–177. https://doi.org/10.1007/s10103-015-1832-4