A well-known study dating back to 1984 demonstrated the effect of views from a window overlooking nature on the recovery times of patients post-abdominal surgery. Based out of a hospital in suburban Pennsylvania, this was a comparative study wherein 23 patients assigned to rooms with windows opening onto natural scenery were studied versus 23 patients assigned to rooms with windows overlooking a brick wall [1]. The former recovered faster, showed better vitals, and demanded fewer painkillers than those facing the brick wall.
And what is nature, if not an abundant display of the color green, among other colors? The green color is known for the soothing effect it evokes in one’s mind. This is probably why most hospitals are themed in plain greens, blues, or grays, instead of red.
The human brain is attuned to being at ease in natural environments. There is a lot of talk going around these days about the need for “green spaces," “landscaping,” and indoor plants in urban areas. These are more than mere beautification projects and have more to do with keeping us sane and healthy. A way to bring greenery close to us, if not the other way around.
Here’s introducing green light therapy — a non-invasive treatment that uses light of a specific wavelength to treat a variety of health conditions. Exposure to green light has been shown to reduce pain, treat dark spots and skin hyperpigmentation, improve sleep quality, alleviate headaches, regulate mood, increase energy levels, and even accelerate wound healing.
The good news is that green light therapy is as simple as it sounds. One can get started with it by using specialized LED devices emitting light of an appropriate wavelength of green, right in their own home! Sound intriguing? Read on to explore the science behind the myriad benefits of green light therapy and how you can employ it to empower your health and wellness.
How does green light therapy work?
Green light therapy utilizes light of a wavelength between 520 and 560 nm. The light is capable of penetrating the skin and interacting with biological tissues, resulting in healing effects while being completely non-invasive. This unique interaction stimulates or interferes with cellular and neurological processes, resulting in both mental and physical health benefits.
Mechanism of green light therapy
Green light therapy has two primary modes of action:
1. Photoreception: This refers to the visual exposure to light and the detection by photoreceptors — cones and rods responsible for color and low-light vision.
When light enters the eye, photoreceptors present in the retina respond by triggering a cascade of signaling pathways in the brain’s suprachiasmatic nucleus (SCN) which regulates circadian rhythms. It also influences mood-regulating neurotransmitters in the central and peripheral nervous system such as serotonin and dopamine, ultimately reducing stress, anxiety, and pain perception.
While certain wavelengths of visible light (red, blue, amber, or white) can exacerbate existing pain, cause migraines, or disrupt sleep, green light can alter these neurotransmitters without causing these side effects [2].
2. Cellular modulation (also called photobiomodulation): This pertains to the cutaneous application of light via the skin to promote healing.
Light in the visible and near-infrared (IR) wavelengths, particularly blue and green light, has been shown to stimulate mitochondrial cytochrome c oxidase, and in turn, the production of adenosine triphosphate (ATP), the energy currency of the cell. This activates various signaling pathways and the increased energy is then utilized for metabolic processes like cell proliferation, migration, gene expression, wound healing, and skin regeneration, which are either healing processes or anti-inflammatory responses in themselves. [3]
This versatile nature of green light, from enhancing neurotransmitters to enhancing cellular processes, makes it a versatile and promising candidate for enhancing overall health and vitality. While visual phototherapy takes hours to take effect, green light penetrating the skin requires just a few minutes of exposure [2], explaining its steadily rising popularity.
Benefits of green light therapy for overall health
Green light therapy for pain relief
We all know how nagging a chronic headache or back pain is. We pop pills in hopes that this debilitating pain would go away. What if all you needed to do was sit under an ambient green light for 20 minutes and watch your pain diminish, leaving you renewed and refreshed?
Green light therapy can reduce pain in a variety of chronic as well as acute conditions. Green light influences the endogenous opioid system, leading to increased production of endorphins and enkephalins (molecules that bind to the μ- and δ-opioid receptors in the central nervous system), activating downstream inhibitory pathways and relieving pain without having to fall into the trap of opioid addiction [4,5].
Further, green LED (GLED) is known to modulate neurotransmitters like serotonin which are crucial molecules in pain perception [4]. This lowers our body’s sensitivity to pain and is effective in chronic pain conditions like migraines and fibromyalgia where conventional therapies often fail to be effective.
Not just that, green light is also known to reduce neuroinflammation, modulate synaptic plasticity, and alter calcium channel activity in dorsal root ganglion neurons, inhibiting the first step of communication between the peripheral and central nervous systems [4,6]. More recently, green light has been found to activate the endocannabinoid system, resulting in decreased osteoarthritis-related pain [7].
Given the ever-rising prevalence of opioid misuse, green light therapy offers a ray of light that is non-invasive, effective, and low risk.
Green light therapy for skin health
Green light therapy aids in skin care and facilitates the healing of injuries. The reason is the enhanced activation of cellular activity — particularly in the mitochondria — increasing the amount of ATP [2]. In other words, skin cells receive a boost and are more equipped to repair and regenerate. This reaction at the cellular level that gets them charged up helps restore the skin, as damaged cells require more energy to repair and regenerate.
In addition, studies show that green light stimulates fibroblast activity and migration [8]. Fibroblasts are the cells responsible for collagen production, essential to the physical and cosmetic quality of dermal structure. As such, more collagen correlates to reduced signs of aging — wrinkles and age lines — while the cosmetic quality and hue improve in appearance.
Green light has anti-inflammatory effects too [3]. Thus, any redness associated with acne, rosacea, and eczema can be relieved using green light. It also reduces redness associated with irritation or inflammation. Green light therapy for skin pigmentation is effective due to its melanin-inhibiting qualities. Studies show that exposure to green light reduces hyperpigmentation and encourages even skin tones; therefore, green light therapy is a viable option for those with melasma and other pigmentation issues [9].
Green light therapy for wound healing
The anti-inflammatory effect of green light has also been observed to be beneficial in wound healing. In a 2016 study, animals treated for burn injuries using GLEDs exhibited a significant decrease in inflammatory cells compared to controls, showing accelerated wound healing [10].
Green light therapy is also highly effective in wound healing by causing increased microcirculation (circulation of blood in the smallest blood vessels), thereby reducing inflammation and promoting tissue repair [4]. Increased microcirculation implies increased oxygen and nutrients to the wound site, and thus, quick healing of the region. As discussed above, GLEDs, as opposed to other wavelengths of light, enhance fibroblast migration by increasing the production of key cytokines and growth factors such as leptin, IL-8, and VEGF, essential for wound healing [8].
In a 2012 study, diabetic mouse models with compromised wound healing were subjected to GLED irradiation. Results showed improved healing evidenced by accelerated wound closure and enhanced tissue regeneration compared to control groups. Therefore, this therapeutic modality has the potential to help people with healing challenges [8].
Green light therapy for better sleep
Sleep disorders affect a vast majority of the adult population, and insomnia is a predominant sleep concern. While sleep disorders are usually treated with drugs to promote sleep, the problem with the sustained use of such sedatives is that they not only come with adverse side effects but also get rendered nearly ineffective after a short time. Therefore, researchers and healthcare providers are on the lookout for alternative treatment solutions. One such solution is light therapy.
Light has a great influence on sleep and psychological health. While we remain exposed to artificial lighting and blue light from our digital screens all day long, which disrupts sleep by altering the circadian rhythm and melatonin production, lights of certain wavelengths, including red and green light, can reset the circadian rhythm for the sleep-deprived [11], help with earlier sleep onset [12], and improve sleep quality.
- Improved cognitive performance: Studies show that even a short hit of bright green light improves brain activity in slightly sleep-deprived individuals. For example, bright green light improves performance by significantly decreasing reaction time on tasks requiring cognitive inhibition — the ability to block out irrelevant stimuli or information and focus on the task [13]. Thus, exposure to this specific hue of light maintains higher levels of cognitive ability during periods of sleep deprivation. This could be particularly helpful for shift workers and students who burn the midnight oil.
- Improved outcomes in sleep disorders: There is some research regarding green light therapy and sleep disorders, including delayed sleep-wake phase disorder (DSWPD). For example, one study evaluating bright green light therapy among DSWPD-afflicted adolescents and young adults found that there was no statistically significant difference in sleep metrics when compared to those receiving red light therapy. However, in the end, the studied populations reported earlier sleep onset, decreased sleep onset latency, and improved daytime functionality after a three-month follow-up period [14]. This means that light therapy is an effective intervention for those suffering from sleep disorders, though more research is needed.
- Green spaces and sleep: Green environments result in longer and improved sleep. That is, access to green spaces is beneficial to sleep. While not necessarily connected to green light exposure, it does, however, support the theory that environmental greenery contributes to better sleep [15]. Ultimately, green light therapy, given the right time of day and duration of exposure, is effective in alleviating sleep disturbances such as circadian rhythm, sleep disorders, and insomnia. It also appears that green light does not harm sleep; but can rather help sleep under specific circumstances, most notably, when testing is related to sleep deprivation.
Green light therapy for better mental health
Mental health difficulties have become a pandemic in their own right in current times. While many turn to medications and psychotherapy for a cure, light therapy could offer a gentler, more economical alternative or combinatorial therapy [16,19] for the same with minimal side effects.
Over the years, researchers have studied the effects of light therapy on mood disorders, focusing primarily on seasonal affective disorder (SAD) [18] or “winter depression," major depressive disorder (MDD) or non-seasonal depression [17, 19, 20], and bipolar depression [21].
A study dating back to 1996 showed that bright light therapy potentially elevates the levels of serotonin in those suffering from SAD [22]. Green light has also been found to be more effective at treating SAD than red light [23].
More recently, green light therapy, in particular, has been found to work synergistically with SSRIs (selective serotonin reuptake inhibitors) for the release of the mood-stabilizing neurotransmitter serotonin, therefore reducing anxiety and alleviating moderate to severe MDD [16].
From the previous section, we also know how green light helps with synchronizing circadian rhythms and the onset of melatonin production through its engagement with the suprachiasmatic nucleus (SCN). This regulates sleep quality and quantity, both of which ultimately influence one’s temperament and overall mental health.
Thus, green light therapy when administered as an adjunct treatment to those with mood disorders can act as a potent mood stabilizer and antidepressant, and help people find a more balanced mood without the complications of drugs. Its potential for easy at-home application renders it further feasible to use. With more research, this could become an integral part of mental health interventions.
Conclusion
In today’s fast-paced world, natural interventions for common ailments often become oblivious to our eyes (quite literally!). It is interesting that something as common as visible light, and its different wavelengths, has the potential to manage and heal a variety of health conditions including pain, sleep, skin health, and mental health.
This article explored the various mechanisms at play behind the therapeutic potential of green light. It is but intuitive, given the calming effect nature and greenery have on one’s mind, body, and soul. We hope this article encourages you to not just explore green light therapy for yourself, but also explore more time outdoors to lift your spirits and heal!
Disclaimer: This blog is intended for informational purposes only and should not be considered medical advice. Before starting any new form of therapy, always consult with a healthcare professional.
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