Light therapy has been used for years to treat an array of medical conditions and diseases, from skin conditions like psoriasis to seasonal affective disorder (SAD) and depression1,2, and most of these studies have focused on broad-spectrum and UV light - the “shortest” types of light waves. But it’s only been more recently that scientists have begun studying the effects of light waves at the other end of the spectrum - red and near infrared (NIR) waves. Like UV waves, red and near infrared waves can penetrate the skin - triggering chemical and other physiological actions deep inside the tissues. And now, medical researchers are beginning to realize how important those mechanisms can be in promoting good health - specifically for the repair of damaged tissues.
Several medical studies have evaluated the effects of red and near infrared light on conditions like multiple sclerosis and specific types of blindness - once thought to be irreversible - and found that application of measured doses of red and NIR acted to heal damaged tissues and restore cellular function. And that’s just the tip of the iceberg. Now, researchers have found that both red and infrared light can also help repair muscle tissue in athletes, helping them train and build muscle tissue more efficiently and compete more effectively. Light therapy has the additional benefit of being effective without the use of potentially harmful drugs. But how does it work?
Light Therapy Fuels Your Muscle Tissue
We all know we need sunlight to stay healthy. Plenty of studies have underscored the role of sunlight in the production of vitamin D, and even back in the first century A.D., Roman scholar and naturalist Pliny the Elder extolled sunlight as “the greatest remedy.” But despite the sun’s longtime reputation as a natural healer, it’s taken us thousands of years to figure out how the sun promotes healing responses in the body - particularly in the muscles. As noted in a previous article, it all starts deep in the cells where tiny structures called mitochondria take in nutrients, process them, and convert them to an energy source that the cells can use to function and repair themselves. Different types of cells have different energy requirements, and that means they contain different numbers of mitochondria. In the case of muscle tissue, which has high energy demands, mitochondria abound. In fact, it’s those high levels of mitochondria inside the muscle tissue that makes red and NIR light therapy so effective in promoting muscle health.
Red and Near Infrared Light Prevent Muscle Fatigue
One of the primary ways light therapy helps promote better muscle health and function is by preventing or limiting muscle fatigue, which naturally occurs as a result of physical activity - especially strenuous exercise and training. In fact, research shows red and infrared light therapy is effective in preventing muscle fatigue and enhancing skeletal muscle performance.3
So how does light therapy reduce muscle fatigue and repair cells? At the most basic level, red and NIR light therapy improve the mitochondria respiration cycle and help mitochondria produce energy more efficiently - and that means muscles are less likely to suffer from fatigue. That’s it in a nutshell, but of course, the physiologic mechanisms behind all these benefits is a lot more complex. For instance, application of red and near infrared light helps promote production of antioxidants which play a central role in reducing oxidative stress associated with muscle fatigue. And they also increase the production of heat proteins - special proteins that help protect cells from stress and early cell death (apoptosis).4,5 Plus, light therapy helps reduce inflammation that can lead to cell damage.6,7,8 Some studies have shown an increase in microcirculation following light therapy, indicating tissues are more able to receive oxygen and other nutrients important for tissue healing – in addition to ridding themselves of toxic byproducts.9
Light Therapy Enhances Muscle Growth
Muscle function and repair are important for improving strength and endurance and reducing fatigue and soreness following workouts and physical activity. But the benefits of red and NIR light therapy don’t stop there. Research shows application of light therapy also promotes the growth of healthy muscle tissue, or muscle hypertrophy, naturally increasing muscle size and bulk - as well as strength.10,11 In fact, one study comparing muscle growth and strength between two groups of athletes - one using light therapy combined with exercise and one using exercise alone - found muscle thickness and strength were significantly improved in those who used light therapy, and results were clearly measurable using ultrasound imaging and isokinetic dynamometry (Figure A).12
Figure A: Percent change (mean ± SE) in peak torque of isometric (PT ISO ) and eccentric (PT ECC ) tests in Control Group (CG), Training Group (TG) and Training + LLLT Group (TLG)
The Long-Term Benefits of Light Therapy
In addition to increases in muscle repair, strength & size, and decreases in muscle fatigue - light therapy also offers long-term benefits for future muscle health and development by targeting muscle stem cells called myosatellite cells. Like other types of stem cells, muscle stem cells remain in an undifferentiated state until activated, at which point they develop into specific types of muscle cells. Just as mitochondria produce energy muscle cells need for optimal function and repair, they also help regulate muscle stem cell activation and differentiation - essentially guiding stem cells into their final form as healthy muscle tissue. Since light therapy enhances mitochondrial action, it may also play an important role in stimulating the growth of new muscle cells and tissue used to “speed up” the repair process following muscle injury or fatigue - improving overall muscle health and function in the long run.
Conclusion: Light Therapy Works
Red and near infrared light therapy shows amazing promise as a drug-free treatment to enhance and improve muscle function, strength, and performance - as well as improving muscle size and bulk to help athletes of all levels train and compete better. And, the natural healing mechanisms stimulated by light therapy can help athletes heal more quickly following injury while also preventing muscle fatigue and soreness that can interfere with both training and competitive performance. Plus, light therapy can be performed in a professional setting or at home, making it extremely accessible. But as noted before, wavelength and intensity are incredibly imperative when it comes to light therapy. Make sure you choose a device that delivers red or near infrared light with the correct wavelength along with an optimal amount of power.
For athletes of all backgrounds - from pros to students to “weekend warriors” - light therapy is a scientifically-backed approach that can have significant and long-lasting benefits.
(1) S. Tami Wong, B.A. Leon Hsu, M.D. Wilson Liao. Phototherapy in Psoriasis: A Review of Mechanisms of Action. J Cutan Med Surg. 2013 Jan-Feb; 17(1): 6–12.
(2) Terman, M. and Terman, J.S. (2005) ‘Light Therapy for Seasonal and Nonseasonal Depression: Efficacy, Protocol, Safety, and Side Effects’, CNS Spectrums, 10(8), pp. 647–663.
(3) de Almeida P1, Lopes-Martins RA, De Marchi T, et al. Red (660 nm) and infrared (830 nm) low-level laser therapy in skeletal muscle fatigue in humans: what is better? Lasers Med Sci. 2012 Mar;27(2):453-8.
(4) Avni D, Levkovitz S, Maltz L, Oron U. Protection of skeletal muscles from ischemic injury: low-level laser therapy increases antioxidant activity. Photomed Laser Surg. 2005;23:273–277.
(5) Rizzi CF, Mauriz JL, Freitas Correa DS, et al. Effects of low-level laser therapy (LLLT) on the nuclear factor (NF)-kappaB signaling pathway in traumatized muscle. Lasers Surg Med. 2006;38:704–713.
(6) Bjordal JM, Lopes-Martins RA, Iversen VV. A randomised, placebo controlled trial of low level laser therapy for activated achilles tendinitis with microdialysis measurement of peritendinous prostaglandin E2 concentrations. Br J Sports Med. 2006;40:76–80.
(7) Aimbire F, Albertini R, Pacheco MT, et al. Low-level laser therapy induces dose-dependent reduction of TNFalpha levels in acute inflammation. Photomed Laser Surg. 2006;24:33–37.
(8) Hemvani N, Chitnis DS, George M, Chammania S. In vitro effect of nitrogen and He-Ne laser on the apoptosis of human polymorphonuclear cells from burn cases and healthy volunteers. Photomed Laser Surg. 2005;23:476–479.
(9) Tullberg M, Alstergren PJ, Ernberg MM. Effects of low-power laser exposure on masseter muscle pain and microcirculation. Pain. 2003;105:89–96.
(10) Halliwell B, Gutteridge JC. Free radicals in biology and medicine. Oxford: Oxford University Press; 2000.
(11) Ferraresi C, Bertucci D, Schiavinato J, et al. Effects of Light-Emitting Diode Therapy on Muscle Hypertrophy, Gene Expression, Performance, Damage, and Delayed-Onset Muscle Soreness: Case-control Study with a Pair of Identical Twins. Am J Phys Med Rehabil. 2016 Oct;95(10):746-57.
(12) Baroni BM1, Rodrigues R, Freire BB, et al. Effect of low-level laser therapy on muscle adaptation to knee extensor eccentric training. Eur J Appl Physiol. 2015 Mar;115(3):639-47.