Blue Light; Sleep, Cancer, and Sports Performance

Sleep: there aren’t enough hours in the day for this insignificant phenomenon that many bypass to get one last job done before the end of the day.  Some claim that sleep isn’t necessary for success, but do we have it wrong?  Are we missing out on opportunities to become successful or has the influx of social media via the technological advances made sleep a thing of the past?  How many have stayed up late at night just to scroll the news feed of your favorite social media platform to catch up on irrelevant news content that floods our brains?  Lets not forget your favorite television series that you must stay up for otherwise you might die if you have to wait until the next evening to see if your favorite male character proposes to his crush, right?

Many may raise the question of, “why is it important to sleep?”  According to the Division of Sleep Medicine at Harvard Medical School, truly understanding sleep is still a process that many scientists are continually researching to better understanding.1  Research has also found that sleep is an important process for not only repairing and rejuvenating the brain, but also for the development and plasticity of the human brain.  So why is sleep an overlooked aspect of overall health and sport performance? In the paragraphs to come, I hope to shed some light on some of the research done regarding blue light and sleep.  We will be looking at what has caused some of the issues with improper sleep hygiene, negative health implications it can pose, how it can be a hindrance to athletic performance, and helpful suggestions that may improve sleep for those who find it near impossible getting quality sleep.

Blue Light
I am sure that many have become accustomed to nightly routines of watching popular television shows, chatting with friends on small handheld devices, and staying up during the late hours to finish work.  Seems fairly senseless, right?  What many of us don’t know is how these small bedtime routines have actually altered our quality of sleep and life.  As we stay awake at night looking at the screens of these devices, our eyes are exposed to what is called blue light, or artificial lighting.  The artificial lighting that comes from many electronic devices affects the human circadian rhythm, which is the body’s natural wake and sleep cycle.2  Why is this significant?  Many studies have been published that continue to find the correlation of increased blue light exposure with the loss of sleep.  Although we get natural blue light from the sun, the amount of time many people look at screens that give off artificial lighting is alarming.  Just think about the number of kids and adults you see during dinner at your local restaurant or watching kids interact after school.  From personal observation, most are interacting in different ways that don’t involve verbal communication, but rather, communicating with the tips of their thumbs.  Moreover, technology and exposure to blue light causes disturbances of the central nervous system, which will put off the production of melatonin (sleep hormone) for up to 90 minutes making falling asleep more difficult.3

The body has a unique way of operating to ensure that many of the processes are functioning properly.  The pineal gland, a small region in the brain that is sensitive to lighting picked up through the eyes, and the suprachiasmatic nucleus, which controls the body’s circadian rhythm, are just two areas that blue light greatly affects.  To show how sensitive the brain is to blue light, think of it this way: you finally made it to bed after a long week with the hopes of getting the best sleep you’ve gotten in weeks; two hours go by and you need to empty your bladder because you’ve consumed water before going to sleep; upon entering the bathroom, you turn the lights on and the bright light shocks you like the New England Patriots Winning the 2017 Super Bowl in overtime; you then walk back to your room like a zombie, get into bed, and bam: you can’t fall asleep.  I am sure this has happened to many of you.  Light, especially at night, may be the cause of your sleepless nights.  As I mentioned above about the pineal gland being sensitive to light, it then signals the body to stop the production of melatonin because it believes it is light outside as a consequence of the late night light exposure.  Melatonin production is decreased, which then causes you to feel awake at three in the morning.

Health Implications of Blue Light
Technology is the now and it is our future, which is apparent amongst the millions of active users on a daily basis.  It is inside classrooms for educational purposes, how we do business, and how many communicate.  But is all of this good for humans?  Over the years more and more research is diving into this topic.  Whether you are a researcher or an observant citizen, you can see how technology has affected humans: good and bad.  Although these technological advances have many good applications in everyday life, there are many dangers that come with it.

Many people in developed countries have become accustomed to different forms of technology, but over the years an increased number of people are suffering from insomnia, obesity, seasonal affective disorder (seasonal depression), and cancer.   Going back to an earlier question: Is all this technology safe for humans?   A recent study conducted by the Breast Cancer Organization concluded that, Women who work at night — factory workers, doctors, nurses, and police officers, for example — have a higher risk of breast cancer compared to women who work during the day.  Other research suggests that women who live in areas with high levels of external light at night (street lights, for example) have a higher risk of breast cancer.”4   Many may raise the question of, how does shift workers or residing in areas that have higher levels of external light have an impact on human health?  If you remember from earlier how I mentioned what blue light is and how it affects the body’s ability to produce melatonin, it begins to make more sense.  These artificial lights that many are exposed to, especially night shift workers, have an internal battle with their body’s natural sense of time and sleep.  This then causes the suppression of melatonin, which many researchers, including physicist Dr. Edward Carome, believe this is the beginning to many health complications. Dr. Carome has discovered that melatonin production at night is important because it acts as a “strong cancer fighting antioxidant.” Additionally, blind men have a decreased risk of prostate cancer than those that can see, and blind women have a decreased risk of breast cancer than those that can see.  The reason for this is because the blind are maximally producing melatonin compared to people that can see who do not maximally produce melatonin.5

Moreover, a study (of many) conducted by Professor David Blask Ph.D, M.D. of Tulane University, experimented with blood samples from cancer patients at different times of the day to monitor melatonin levels.  What Dr. Blask found was “exposure of human subject to bright light at night suppresses the nocturnal circadian melatonin signal resulting in high, daytime-like rates of tumor metabolism and grown.”6  This is furthering evidence of what has been found by many researchers.  From the number of studies, one could make a safe assumption that melatonin production and sleep are important necessities for health and well-being.

Sports Performance
As a former high school and collegiate athlete, working out, eating healthy (what I thought was healthy), and practices played a major role in everyday life. During my athletic career, there were only a few times sleep was a topic of discussion (Yes, there is a good chance that I was zoned out like a squirrel in a tree on a warm spring morning and missed these conversations, but that’s besides the point).  Like many, the small things are often viewed as insignificant and if it can’t be measured in a weight room, well, it really isn’t important.  A significant portion of increased athletic performance and adaptations come from the sleep we get in the days and weeks leading up to practices and competitions3. Also, the body needs the proper amount of sleep for natural responses to occur such as the natural release of the human growth hormone (HGH), muscle repair/gains, and maintenance.  In a study published by the National Strength and Conditioning Association athletes require a greater quantity of sleep to recover sufficiently from injury, intense training periods, and competition .8 “Training is just a small part of getting bigger, faster, and stronger.  Some of the most important responses/adaptations happen during sleep.”3

Assuming that most of us have gone through a night or two where sleep was nearly impossible, think back on how you felt the next day.  Maybe you felt sluggish or moody, had increased junk food cravings, or felt a decrease in your thought process.  These examples sometimes become more apparent with athletes that have had a rough night of sleep.  Many great coaches are able to sense this without any high-end technology by reading body language. Sometimes our eyes are the best tools to assess when athletes have had a good or bad night of sleep.  According to John Underwood’s study on sleep and athletic performance, sleep loss can result in an eleven percent reduction in time to exhaustion during exercise.  Additionally, “when exhausted, blood flow to the brain decreases.  Blood flow is required for pre-movement and balance. When the brain doesn’t work, the body doesn’t work.”3 This is no coincidence given that our brain is the control center for many of the functions that take place in our bodies. Sleep is a must; it can be the difference between a great performance and mediocre performance.

Moreover, because the education of sleep hygiene is sometimes forgotten, many athletes look for different alternatives to offset sleep debt.  Some athletes have resorted to various supplements to help increase energy, with energy drinks being one of the most popular.  Side note: if you are someone who depends on energy drinks to get through the day or to get you “amped” for your gym session, this is a problem.  In most cases, if a sound nutritional and sleep routine is followed, this should give one optimal levels of energy.  Caffeine supplementation is a widely talk about topic within the sports performance field, but athletes sometimes become dependent.  A study was conducted with a group of Navy Seals, which yielded positive results to mental and physical performance when consuming caffeine.  It is important for athletes and coaches to understand that the stimulation of the central nervous system can sometimes put an athlete at an over-aroused state, which can lead to declined performances.3  Although adult athletes have shown positive effects from caffeine, parents have been advised to prohibit young athletes under eighteen the consumption of energy drinks.  A study published by the United States of America Football Organization, warns about increased anxiety and arrhythmias as a result of children who take caffeinated energy drinks.  In addition, the same study found that individuals who ingest caffeinated energy drinks more often suffer more mistakes because of over-arousal, an increased heart rate, increased blood pressure, and a disrupted sleep cycle.9

We often forget the importance of good brain health.  The brain accounts for many functions within the body, but often the last to get attention when training. Although caffeine has been shown to increase mental and physical performance, athletes and coaches must understand the importance of getting proper sleep and naturally nourishing the brain instead of depending on stimulants to overcome sleep deficits and to increase performance.  I am not saying that caffeine is bad.  Research has found advanced athletes benefiting from caffeine.  However, what I am saying is that young athletes should not be turning to these types of supplements/stimulants to offset sleep debt or a bad nutritional diet.  There are many natural ways to increase energy that can be more beneficial than teaching youth athletes that they can get a quick and easy fix to mask a bad diet through beverages or supplementation.

How to improve sleep quality
Many alternatives exist when trying to implement consistency with sleeping patterns.  One of the most popular choices amongst many Americans comes in the form of medication: synthetic melatonin. Although the synthetic form of melatonin does help some with sleep, many become dependent, which affects the human body’s natural ability to produce melatonin.  The Sleep Foundation advises those that choose to consume synthetic melatonin to be cautious because it is not regulated by the Food and Drug Administration. “For melatonin to be helpful, the correct dosage, method, and time of day it is taken must be appropriate to the sleep problems.10 Like many over the counter supplements, it is important to do a little homework before purchasing.

If melatonin supplementation is not a good solution, then what is the best or next alternative?  Consistent sleep patterns have been shown to help with sleep hygiene.  A structured schedule that consistently has one going to sleep at the same time and waking up at the right time can help with those that suffer from insomnia or other sleeping disruptions.  In addition, there are many applications one can download, such as The Calm App, which provides guided meditation and breathing techniques.  This is something I have tried and saw great results with. Furthermore, stretching before bed has been a beneficial and calming practice I have implemented to increase sleep.  Both have benefited me in my own search for better sleep, but decreasing blue light has been the best choice for increasing sleep.

Here are a few sleep suggestions that the Harvard Medical School Heath News Letter suggests 11:
-Avoid looking at bright screens beginning two to three hours before bed.

-Expose yourself to lots of natural bright light during the day, which will boost your ability to sleep at night, as well as your mood and alertness during daylight.

-Use dim red lights for night-lights. Red light has the least power to shift circadian rhythm and suppress melatonin.

Here is a list from research articles on the effects of sleep deprivation
Those who consistently use energy drinks are 1.8 times more likely to report morning sleepiness than those who do not use energy drinks.3

Artificial lighting could be making us frail, withering muscles and making bones more fragile.12

Lack of sleep impairs information retrieval, or the ability to access learned information.3

Students who pull all-nighters: 2.95 GPA, Students who don’t pull all nighters: 3.20 GPA.3

Athletes build up sleep reserves or deficits over1-3 days.3

Sleep deprivation leads to disruption of training intensity and performance at competition.13

A growing body of evidence suggests that a desynchronization of circadian rhythms may play a role in various tumoral diseases, diabetes, obesity, and depression.14

I’m pretty sure that at least many of the sleep disorders we are facing epidemically are related to evening or nighttime light.14

Sleep-related problems affect 50–70 million U.S. men and women of all ages.14

Disrupting this circadian rhythm has also been linked to medical issues like depression, obesity, breast and prostate cancer, and cardiovascular disease. It’s even associated with sleep disorders like insomnia and delayed phase sleep disorder, possibly because it causes the suppression of melatonin, a sleep-inducing hormone.15

Eve Van Cauter, PhD, who termed sleep deprivation “the royal route to obesity.”16

“Continued sleep shortages contribute to depression, heart disease, lowered immunity, obesity, and type 2 diabetes, among other illnesses.”17

Brining it all together:
Over time, blue light has been shown to affect not only sleeping patterns, but also the formation of cancer cells.  Blue light also increases the likelihood of depression, obesity, and seasonal affective disorder – just to name a few.  This is a growing topic within health fields and sports performance, but we must continue to do our homework to get a better understanding of our less than optimal sleep patterns.  For years I have often wondered and grew curious to some of the changes that I have gone through (eating patterns, mood, decreased motivation), and it was not until I started taking a deeper look into sleep and its effects that I began to get a better understanding of the importance of this amazing phenomenon.  Being an athlete and working with many athletes, I often question whether us coaches are giving today’s youth the best information to not only positively impact their athletic careers, but to also impact their lives after sports.  Obesity, depression, and sports injuries are continually growing and some of the same information continues to be regurgitated in different ways, (better training models, nutrition, and the list goes on), but I often find sleep a topic that many coaches briefly talk about. Although there is much more to learn on this topic (and I have only hit the surface), with my findings I hope to help many become more aware of the importance of understanding blue light and how it can hinder our sleep patterns.  Technology is increasing and this may be the devil’s recipe for some of the health issues many of us face when dealing with sleep. Sleep is like water, you need it to function and survive.  Don’t let the quality of your life decrease because of your sleep hygiene.

Kendrique Coats
Owner, Coats Performance LLC


If you liked this and you found it to be helpful, please help us spreading the word by sharing this via social media or with someone you know of that suffers from these issues.  Also, there will be more information to come in regard to improving sleep quality.  Please be sure to follow us on social media (Instagram/Facebook) at Coats Performance for additional information.




1) MG, Frank. “The Mystery of Sleep Function.” Why Do We Sleep, Anyway? | Healthy Sleep. Sleep Medicine at Harvard Medical School, 18 Dec. 2007. Web. 05 Apr. 2017.

2) “Blue Light and Your Eyes.” Prevent Blindness. N.p., Mar. 2017. Web. 26 Mar. 2017.

3) Underwood, John. “Technology and Sleep.”Sleep and Recovery. Life of an Athlete, n.d. Web. 26 Mar. 2017

4) “Light Exposure at Night.” N.p., n.d. Web. 01 Apr. 2017.

5) Carome, Dr. Edward. “Is Blue Light the New Smoking.” Interview by Daniel Vitalis. Audio blog post. Rewild Yourself. N.p., 1 Sept. 2015. Web. 1 Apr. 2017.

6) Blask, Dr. David E. “Research Interests.” Structural & Cellular Biology. Tulane University- School of Medince, n.d. Web. 1 Apr. 2017.

8) Teng E, Lastella M, Roach GD, and Sargent C. The effect of trainign load on sleep quality and sleep perception in elite male cyclists. In: Little Clock, Big Clock: Molecular to Physiological Clocks. Kennedy GA and Sargent C, eds. Melbourne: Chronobiology Society, 2011. pp. 5–10.

9) Frollo, Joe. “Experts Warn against Caffeinated Energy Drinks for Young Athletes.” United States of America Football, 20 Feb. 2015. Web. 31 Mar. 2017.

10) “Melatonin and Sleep.” Sleep Topics. National Sleep Foundation, n.d. Web. 1 Apr. 2017.

11) Publications, Harvard Health. “Blue Light Has a Dark Side.” Harvard Health. N.p., 2 Sept. 2015. Web. 01 Apr. 2017.

12) Johnston, Ian. “Artificial Light Could Be Making Us Prematurely Frail.” The Independent. Independent Digital News and Media, 14 July 2016. Web. 05 Apr. 2017.

13) Souissi N, Chtourou H, Aloui A, Hammouda O, Dogui M, Chaouchi A, and Chamari K. Effects of time of day and partial sleep deprivation on short term maximal performnces of judo competitors. J Strength Cond Res 27: 2473–2480, 2013.

14) Holzman, David C. “What’s in a Color? The Unique Human Health Effects of Blue Light.” Environmental Health Perspectives. National Institute of Environmental Health Sciences, Jan. 2010. Web. 05 Apr. 2017

15) “External Lights Affect Your Sleep.” Sleep.Org. N.p., n.d. Web. 05 Apr. 2017.

16) Cauter, Eve Van. “Obesity and Sleep.” Sleep Topics. National Sleep Foundation, 2003. Web. 05 Apr. 2017.

17) Reports, Consumer. “Why Americans Can’t Sleep.” Consumer Reports, 14 Jan. 2016. Web. 05 Apr. 2017.






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