Sarah Turner is the Founder of CeraThrive, a wellness company specialising in photobiomodulation and its impact on the gut-brain connection. With a background in neuroscience and biohacking, Sarah is dedicated to advancing innovative therapies that optimise health, longevity, and performance.
Light is more than just what we see; it is a fundamental force that shapes our health, mood, and daily experiences. From the energizing morning sun to the artificial glow of screens, light plays a critical role in regulating our body’s internal clock, influencing productivity, and even affecting our emotional well-being.
The electromagnetic spectrum
Light impacts our everyday lives in more ways than we can imagine. It affects how we feel both emotionally and physically. It influences our health as well as productivity at the office and at home. If this is new information to you, don’t worry; this book will clear up everything. For now, let’s begin by discussing what makes up light.
What is light?
Light is simply a part of the electromagnetic spectrum, which includes radio waves, infrared radiation, visible light, microwaves, gamma rays, and x-rays. The human eye can only see a limited part of the electromagnetic spectrum (visible light). Just like other forms of electromagnetic radiation, visible light is made up of electromagnetic waves.
The light that you see with your naked eye is actually made up of multiple colors with varying frequencies and wavelengths, from red (longest wavelength and lowest frequency) to violet (shortest wavelength and highest frequency). In between this range, we have other orange, yellow, green, and blue lights.
The sun
The main source of light and energy on Earth is the sun. This energy is propagated along rays in the form of waves, hence the term wavelength. Even though the sun is considered to be the primary source of visible light, it emits radiation right across the electromagnetic spectrum. The table below depicts the average wavelengths of various colors of light found within natural visible light.
Color | Wavelength (nanometer, nm) |
Violet | 400 |
Indigo | 425 |
Blue | 470 |
Aqua | 490 |
Green | 550 |
Yellow | 600 |
Orange | 630 |
Red | 665 |
Dark Red | 700 |
Waves that have wavelengths slightly shorter than purple light, and thus have slightly higher frequencies and higher energy levels, are called ultraviolet (as in, beyond violet) or UV light or UV radiation. We cannot see UV light; however, some animals, like honeybees, can.
Morning sun vs. afternoon sun
Recently, there has been a surge in research studies looking into morning sunlight and late afternoon sunlight and their possible links to health and well-being. For instance, in one study published in 2014, researchers found that exposure to morning sun can help people lose weight. The study established that morning light triggers genes that promote metabolism in the body. According to the lead author of the study, Dr. Phyllis Zee, Professor of Neurology at Northwestern University Feinberg School of Medicine, “If a person doesn't get sufficient light at the appropriate time of day, it could de-synchronize your internal body clock, which is known to alter metabolism and can lead to weight gain”.¹
In another study, scientists concluded that exposure to afternoon sun raises the risk of developing cancer fivefold. According to the lead researcher, Professor Aziz Sancar of the University of North Carolina, the protein used by your body to repair damage from UV light is most active before noon.²
Morning sun is also good for your mood. It stimulates the production of serotonin, a neurotransmitter in the brain that regulates mood. It is not uncommon for psychiatrists to encourage depression patients to take as much sunlight as possible. This is because sunlight triggers the release of endorphins, hence reducing depression symptoms. Lack of adequate sunlight exposure causes your serotonin levels to dip to very low levels, putting you at a higher risk for developing a form of depression known as seasonal affective disorder (SAD).
Sunlight vs. indoor lighting
Sunlight is full spectrum and dynamic. Full spectrum means that light contains all the colors of the rainbow, whereas dynamic means that the intensity and mix of colors changes with the time of day. On the other hand, artificial light sources emit a static spectrum, which means their mix of colors cannot change with the time of day. As a result, artificial light sources are designed to either replicate daylight or evening light. However, artificial lighting can be modified and used safely to mimic the appropriate intensity and color spectrum for a particular time of day.
Sunlight or natural light has a number of benefits over indoor lighting. For starters, it boosts your vitamin D intake, which helps you develop stronger bones and reduce the risk of heart disease and cancers. Exposure to natural lighting has also been found to alleviate depression symptoms as well as improve sleep. We discuss more on this in the next section.
The effect of morning sun on cortisol
Morning sunlight reinforces a person’s natural circadian rhythm. The body’s biological processes, such as energy levels, temperature, appetite, and hormonal production, are influenced by its circadian system. The body’s core temperature, for instance, changes throughout the day. It is highest during the day and lowest early in the morning, before waking up. As the body prepares to wake up, cortisol is released to energize your body and warm up your core body temperature. After sunset, your body begins to cool, thereby triggering the production of melatonin, the hormone that regulates sleep.³
Exposing your eyes to morning sunlight signals your brain to increase the production of cortisol while suppressing the production of melatonin. Also, the warmth from sunlight increases your core body temperature, which in turn triggers the production of cortisol to energize you.
Circadian biology
The circadian rhythm is simply your body’s natural, internal system that is designed to regulate the sleep and wake cycles during a 24-hour period. It is controlled by the brain’s light receptors, which receive signals to initiate various processes. These signals vary throughout the day, which is why your circadian rhythm typically coincides with the sun’s cycle.
So, how does it work? Well, this body’s internal master clock is located in the suprachiasmatic nucleus (SCN) of the brain’s hypothalamus. It receives light signals from the eye’s retina, which it then sends to different parts of the brain, such as the pineal gland, to release or suppress melatonin.
It explains why we are most alert during the day and ready to sleep when darkness falls. If you find yourself struggling to fall asleep or wake up at a set time or even catch yourself yawning throughout most of the day, it could be an indicator that your circadian rhythm is off.
Your body’s circadian rhythm stays balanced when you follow its natural cues for sleeping and waking up. A change in schedule, such as pulling an all-nighter at the office or staying up late watching movies, can seriously disrupt your internal body clock.⁴
Maintain a healthy circadian rhythm
Disrupting your natural circadian rhythm could potentially increase your risk for developing cardiovascular disease and a weak immune function. Luckily, there are habits that you can begin to cultivate to support a healthy circadian rhythm. Highlighted below are some of these habits.
1. Keep your sleep schedule consistent
Going to bed every night and waking up around the same time every morning helps you build a consistent sleep-wake routine. It trains your master clock to stick to the routine while keeping you from having your sleep interrupted. Should you have a restless night, try as much as possible to resist the urge to catch up on sleep during the day, as this will only disrupt your cycle more.
2. Don’t nap in the afternoon
Make a point of staying active throughout the day. It helps balance your circadian rhythm. That feeling of laziness after lunch makes it harder to resist sleep. You can manage this by staying active in the afternoon. The longer you are awake, the more your body will want to sleep toward the end of the day.
3. Take in the morning sun
As already mentioned before, morning light suppresses melatonin production. This exposure resets your internal clock.
A word on night sky light pollution
Night sky pollution is marked by excessive, inappropriate, and unwanted artificial light. Its consequences range from the disruption of ecosystems to adverse health impacts on humans and animals. Some experts have compared light pollution to widespread, long-term damage on land caused by a toxic chemical spill. The major components of night sky pollution include:
Urban sky glow: using brightening artificial light over inhabited areas
Glare: excessive brightness that causes visual discomfort
Light trespass: lighting up areas (private) where light is neither wanted nor needed
Clutter: excessive groupings of bright light sources, usually in urban areas
Night light pollution is more of a modern problem brought by increased urbanization. To most people, night light pollution may seem harmless; however, there is a growing body of evidence that links this form of pollution to serious impacts on human health.
You already know that exposure to light while sleeping suppresses the production of melanin. When your body’s melanin levels are low, stress hormones are triggered, causing headaches, anxiety, and fatigue. Also, the glare reduces the visual function of the eyes.
Blue light toxicity
New scientific studies are unearthing the relationship between high-energy blue light and eye problems as well as disruption of the body’s circadian rhythms. Now, blue light is not all bad. In fact, we can thank blue light wavelengths for keeping us attentive and in a good mood during the day. However, at night, blue light has proven to be quite disruptive. The proliferation of electronic devices with screens, alongside energy-efficient lighting, continues to increase our exposure to blue light wavelengths after sunset. It should be noted that blue light is not actually blue in color; it looks white to the naked eye. Normally, if you work indoors or in an enclosed office setting, you are probably exposed to high levels of blue light.
According to a 2018 study, researchers found that exposure to artificial blue light triggered a chemical reaction in retinal molecules, thereby oxidizing them to create a toxic chemical species. This leads to irreparable damage to retinal cells. Ajith Karunarathne, a co-author of the study, believes that the changes in retinal seen in the study could be linked to macular degeneration, an incurable disease that blurs or even eliminates vision.⁵
Does blue light exist in sunlight? Of course, it does. The authors of the study, however, recon we do not spend as much time staring at the sun as we do staring at our cellphones and computers. As a matter of fact, a 2016 survey found that Americans spend nearly 11 hours a day staring at some form of a digital screen.⁶
How can you reduce blue light at your workplace?
The following tips can help you minimize blue light toxicity at work and at home.
Wear blue light-blocking glasses. There are a number of decent blue light-blocking glasses brands in the market today at affordable prices.
Limit your screen time when you are not working to avoid eye fatigue and muscle strain.
Consider installing an app such as F.lux, which reduces blue light exposure, on your devices.
Change your indoor bulbs to low-blue-light bulbs. Energy efficient light bulbs such as fluorescent lights, some LED lights, and halogen lights emit large amounts of artificial blue-containing 'white light'.
The benefits of red light
For decades, light therapy has been used in the treatment of various ailments, pains, and disorders. Also known as photo-bio-modulation (PBM), this form of therapy is founded on the safe healing properties of the low-level red wavelength in the electromagnetic spectrum. It can be used as an antidote itself or as a trigger to activate the healing properties of the body. Ideally, the red wavelengths can penetrate your skin up to a depth of 10 millimeters; however, you will not feel any pain or discomfort. It is not a laser treatment.⁷
How does a red light work?
So, how does a red light achieve this? Well, when you are exposed to red light, it activates a chemical reaction within your cells through the chromophores, thus providing the mitochondria with energy. Once the mitochondria are charged up, energy molecules called adenosine triphosphate (ATP) are created. This energy is then harnessed into important bodily functions such as damage repair to cells and boosting immune function. To put this into better perspective, if your body is deprived of ATP energy for a few seconds, your life will simply cease to exist.
Outlined below are some of the most popular benefits of red light.
1. It stimulates our blood circulation and the functioning of fibroblasts
This makes it easier for the body to self-heal and treat injuries such as burns and amputation wounds. Optimally functioning fibroblasts also stimulate the production of the proteins collagen and elastin. These proteins are responsible for maintaining the structural support of our skin. Collagen makes up more than half of the protein found in our skin, so by having more of it present, wrinkles, stretch lines, and other skin blemishes begin to fade and become less noticeable.
2. It boosts fat metabolism
Although there is still ongoing research, red light is widely believed to have properties that promote fat metabolism in the body. Some experts believe that it may be a result of the red light’s ability to disperse fat storage cells (adipocytes).
3. It promotes natural detoxification
By boosting the function of the lymphatic system, red light allows your immune system to be healthy.
When red light penetrates your skin to catalyze cellular activities, it allows more blood to flow, hence facilitating the delivery of more nutrients and oxygen throughout your body.
Protecting mental health
A majority of people will spend about a third of their lives in the workplace. The working class today spends more waking hours at the office than at home; therefore, protecting the mental health of workers must be a top priority for all organizations. Despite this, we still see shocking statistics in regard to the mental health of workers. For instance, one survey found that nearly half of Canada’s working class said that their workplace is a “frequent or ongoing source of feelings of depression, anxiety or other mental illness”.⁸ In another survey, 82% of American employees with mental health issues said that their health impacted their work.⁹
Night shifts, otherwise known as graveyard shifts, are increasingly becoming customary for all big and middle-level companies. Thanks to increased competition, the appetite for attracting more customers while keeping your expenses low to maximize revenue is here to stay. Unfortunately, not much is talked about with respect to the impact, specifically the mental health impact, that night shifts have on people. Earlier on, we had discussed in detail how staying up at night disrupts a person’s circadian rhythm, thereby creating a hormonal imbalance in the body. Among the greatest causes for concern is the fact that two of the symptoms of disrupted circadian rhythm are depression and fatigue. For people working on jobs that typically require you to be on high alert, this is a very dangerous combination. Think of a late-night truck driver or a surgeon who’s pulling a night shift, consistently exposing their eyes to artificial blue light. One mistake could result in the death of a person.
Shift workers will often downplay this by saying that they sleep during the day and work at night, so, “it’s kind of the same thing”. Unfortunately, no, it is not the same thing. Struggling to sleep in darkened rooms during the day and working in a brightly lit space with a ton of toxic blue light at night are pitting their internal and external circadian rhythm factors against each other.¹⁰ This creates a kind of depressive state similar to seasonal affective disorder.
Since the circadian rhythm tends to be stubborn and does not like sudden changes, experts caution against doing shift work for small blocks of time, such as every other week. Instead, do shift work in larger blocks of time, such as a few months, to give your body time to adapt to the new circadian rhythm.
Sarah Turner, CEO CeraThrive and Red Light Therapy Expert
Sarah Turner is the founder of CeraThrive, a company advancing wellness through photobiomodulation and its impact on the gut-brain connection. With a background in neuroscience and biohacking, she is passionate about exploring innovative therapies to optimise health and performance. Sarah also co-hosts the "Rebel Scientist" podcast, where she explores cutting-edge topics in wellness and longevity.
References:
Marla Paul, North Western Medicine (2014): “Study Links Light Exposure to Weight”.
Sadie Whitelocks, Daily Mail Online (2011): “Why morning sunbathing is better for you as it cuts the risk of skin cancer”.
Amelia Willson, Tuck (2018): “The importance of morning sunlight for better sleep”.
Editorial Staff, INTEGRIS (2019): “What is Your Circadian Rhythm and Why is it Important?”
Kasun Ratnayake, John L. Payton, O. Harshana Lakmal & Ajith Karunarathne, Scientific Reports (2018): “Blue light excited retinal intercepts cellular signaling”.
Jacqueline Howard, CNN (2016): “Americans devote more than 10 hours a day to screen time, and growing”.
Editorial Staff, Green Child Magazine (2019): “The Benefits of Red Light Therapy for Cellular Health and Healing”.
Morneau Shepell, Media Room (2017): “Morneau Shepell finds organizational change linked to physical and mental health sick leave”.
Miller, M. C. (2006): Mind and Mood After a Heart Attack. Harvard Mental Health Letter, 1.
Jeffrey Joyner, Chron (2019): “Depression & Working the Night Shift”.
