Throughout human history, our bodies have adjusted to the rhythm dictated by one consistent factor: light. This circadian rhythm follows the 24-hour cycle of Earth’s day and night, which is regulated by the suprachiasmatic nucleus (your master clock) in the brain that communicates with all cellular clocks. Our cells rely on light clocks to schedule certain tasks. The code from light frequencies in our environment controls our daily functions, depending on the time of day and season.However, modern lifestyles have created an abnormal light environment that’s disrupting our natural circadian rhythm, leading to increased inflammation, hormone and neurotransmitter dysregulation, insomnia, and accelerated aging. To understand the impact of light on our health, we must first recognize the various wavelengths of visible and invisible light that comprise it. 

Sunlight is made of multiple different frequencies of light, both visible and invisible. This includes the spectrum from ultraviolet light to infrared radiation. Our bodies have evolved to adjust to the rhythm dictated by this natural source of light. Our cells are informed when to perform certain tasks and functions as dictated by environmental influences such as the time of day or year. Modern lifestyles have created an abnormal light environment that disrupts our natural circadian rhythm. This can result in multiple health issues and increased cellular aging. Understanding the importance of light on our health is essential to create an optimal environment for longevity. 

In many ways, exposure to different wavelengths of light throughout the day can be compared to taking an outdoor electromagnetic multivitamin. Each wavelength serves a particular purpose. More than half of sunlight consists of red and infrared frequencies, which are recognized for their therapeutic and rejuvenating qualities. These frequencies can stimulate the production of melatonin in the skin, preserve skin cells, slow down aging caused by sun exposure, enhance ATP production in muscles, regulate the sleep-wake cycle, and contribute to general wellbeing when exposed both morning and night. Furthermore, red and infrared light can prime the skin at sunrise, making it better able to handle any UV or visible light exposure throughout the day. During sunset, the red and infrared wavelengths in natural light help to repair the damage caused by UV exposure. This highlights the crucial role of these anti-inflammatory frequencies in maintaining good health and prolonging lifespan and gives insight into why they are always a significant part of natural light regardless of other wavelengths present.

Despite its bad reputation, UV light provides several positive benefits to human physiology and is necessary for optimal health. There are three types of UV rays with only two impacting humans significantly: UV-A, which causes us to tan and stimulates a melanocyte-stimulating hormone; UV-B, which helps create vitamin D; and finally, the third type (UV-C) is not present in our planet since it is blocked out by the atmosphere. Exposure to UV light not only increases Vitamin D but also boosts Nitric Oxide production, improves blood pressure, and activates neuroendocrine pathways.

Visible light is the part of the electromagnetic spectrum that falls between infrared and ultraviolet light. The blue and green wavelengths of visible light play an important role in regulating human circadian rhythms and are naturally present during the day. The amount of light we are exposed to during the day has an impact on our hormone and neurotransmitter levels. The levels of hormones and neurotransmitters increase in proportion to the increase in visible light exposure. 

Exposure to artificial blue light at night suppresses melatonin production, which can disrupt sleep and hinder our body’s rejuvenation and restoration process. Additionally, blue light causes inflammation in our fatty tissue beneath the skin, which can go unnoticed as it does not cause sunburn, unlike natural light excess. This inflammation lasts longer and can be harmful if left unchecked. Inflammation can decrease the efficiency of mitochondria in producing energy in cells, making it important to prioritize the optimization of mitochondria for energy production to maintain healthy cellular functions. 

By recognizing the importance of light for optimal health and longevity, you can create an environment conducive to better well-being. Taking advantage of natural sunlight during the day combined with adequate lighting at night helps ensure that you remain in sync with your circadian rhythm to allow healthy hormones and neurotransmitter levels. Practicing intelligent sun exposure for Vitamin D benefits, as well as using light therapy to address seasonal depression, improve immune function, dampen inflammation, and increase the quality and quantity of our years is how nature helps your inner light shine bright! With this blog post, we hope we have been able to shed more light (pun intended) on how essential it is for us to keep an eye on the way we use available sources of illumination in our daily lives. In upcoming blogs, we will discuss the practical application of how to let more light into your life!

Stay safe, stay healthy, and let your light shine! 

References:
Spada, J. (2017). The Circadian Code: Lose Weight, Supercharge Your Energy, and Transform Your Health from Morning to Midnight. Penguin Random House.
Hatori, M., Gronfier, C., Van Gelder, R. N., Bernstein, P. S., Carreras, J., Panda, S., … & Furukawa, T. (2017). Global rise of potential health hazards caused by blue light-induced circadian disruption in modern aging societies. npj Aging and Mechanisms of Disease, 3(1), 1-10.
Gupta, A., & Daigle, K. (2019). The impact of blue light on health: a literature review. Healthcare, 7(2), 51.
Hamblin, M. R. (2018). Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophysics, 5(3), 129-149.
Zivkovic, R. V., Carneiro, L. A., Carvalho-Silva, M., & Brandão-Neto, J. (2020). Effects of light on mitochondrial physiology: implications for aging and neurodegeneration. Frontiers in Neuroscience, 14, 634.