We spend most of our time staring at screens at work, home, wherever we are. But you may not realize, but display screens of electronic notebooks, computers, smartphones, and other digital devices emit a significant amount of blue light. That blue light from staring at the screen all day or throughout the night can be unhealthy. This unhealthy habit can affect your vision, make you more sedentary and contribute to weight gain, as well as affect the quality sleep. Most importantly, lack of sleep can intensify pain sensation which is bad news for persons with chronic and painful conditions.

Blue light and sleep
How many times have you looked for tips for better sleep only to realize that almost all sources you find suggest ditching TV from your room and avoid using phone and tablet in bed? Even though this happens all the time, we are inclined to dismiss those tips. But, it turns out they were right! TV and phone screen can, indeed, lessen the quality of sleep.

The July 2017 issue of journal Ophthalmic and Physiological Optics published an interesting study whose primary objective was to investigate whether melatonin level and sleep quality could be modulated by decreasing nighttime input to the intrinsically photosensitive retinal ganglion cells (ipRGCs). Basically, the ipRGCs are receptors activated by blue light and they work by suppressing melatonin, a hormone that regulates the sleep-wake cycle. For the purpose of the study, scientists from the University of Houston enrolled 21 participants ages 17 to 42. Subjects wore short wavelength-blocking glasses three hours prior to the bedtime for two weeks while performing their nightly digital routine. Findings demonstrated a 58% increase in the nighttime melatonin levels, which is even higher than an increase from over-the-counter supplements.

What do these findings mean? They indicate that exposure to blue light at night decreases sleep quality by decreasing melatonin. On the other hand, the use of blocking glasses decreased input to the photoreceptors and improved quality of sleep in subjects.

Another article which was recently published in the Molecular Vision journal, reviews studies which analyzed current evidence on sleep quality and blue light. The review showed that exposure to blue light enhances alertness and stimulates cognitive functions, thus keeping you awake at night. This explains why you don’t feel sleepy after going to bed – you watch TV or use your phone and the blue light eliminates sleepiness while increasing alertness. The review found that exposure to blue light, particularly long-term, has a negative impact on circadian rhythm and overall quality of sleep.

Can blue light aggravate pain?
Spending too much time watching TV in bed or using your phone can aggravate pain intensity as well. How? Numerous mechanisms could play a role, but disrupted sleep is the most thoroughly explored. It’s not a myth, but a scientifically proven fact that lack of sleep is correlated with bad pain outcomes. For example, a study from the May 2017 issue of journal Nature Medicine found a strong connection between sleep deprivation and pain sensitivity. In fact, five consecutive days of moderate sleep deprivation significantly exacerbated pain sensitivity in otherwise healthy mice. The biggest revelation of this study is that painkillers didn’t work when mice were sleep deprived. This means that if your devices keep you awake, not only will they prevent you from falling asleep, but they will also decrease the efficacy of painkillers.

The impact of blue light on sleep quality and the influence of sleep deprivation on pain intensity should not be discounted. When it comes to both sleep and pain, everything you do can either help you or make things worse.

Tips for healthier sleep

Unfortunately, the importance of sleep is underestimated lately. It’s easy to think “I’ll sleep longer over the weekend”, or “I’m not sleepy anymore and I’ll sleep later”. Getting 7 to 9 hours a sleep every night is strongly recommended. A good night’s rest boosts your energy levels and improves productivity. It is also vital for the strong immune system, cognitive abilities, metabolism, and multiple other benefits. Here are some important tips that will help you get enough sleep and also tackle pain more efficiently:

Set up a regular sleep schedule – it’s not just about getting about 7 or 9 hours of sleep, but you should go to bed every night at the same time and wake up every morning at the same time, as well. It’s all about having schedule.
Remove the TV from your bedroom – chances are you have a TV in your living room and bedroom, but you should definitely sleep in a room without TV. That way, you won’t feel tempted to turn your TV on and watch. As a result, you’ll still feel sleepy and you won’t be sleep deprived. This also means that you will reduce the risk for enhanced pain sensitivity
Use an alarm clock – many people use their phones to set up an alarm to wake up in the morning. Then, you place the phone on the nightstand or next to the pillow and check it throughout the night. You end up spending hours on your phone instead of sleeping. Navigate around this problem by using a good ol’ alarm clock or set the alarm on the phone, but don’t keep it next to your bed

All of us are exposed to blue light, but to different degrees. Screens of devices we use emit blue light and affect our sleep quality, damage our eyes, and deplete energy levels. Blue light can also heighten migraine pain. Also, sleep deprivation can intensify pain and decrease the efficacy of painkillers. You can overcome this problem easily; strive to reduce exposure to blue light before bedtime or when you’re in bed.


Ostrin LA, Abbott KS, Queener HM. Attenuation of short wavelengths alters sleep and the ipRGC pupil response. Ophthalmic and Physiological Optics 2017 Jul;37(4):440-50. Doi: 10.1111/opo.12385 http://onlinelibrary.wiley.com/doi/10.1111/opo.12385/abstract;jsessionid=08F31EB60646DB311B5087B6FDC0FD0E.f02t01
Tosini G, Ferguson I, Tsubota K. Effects of blue light on the circadian system and eye physiology. Molecular Vision. 2016;22:61-72. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734149/

Montagni I, Guichard E, Carpenet C, et al. Screen time exposure and reporting of headaches in young adults: a cross-sectional study. Cephalagia 2015 Dec;36(11):1020-27. Doi: 10.1177/0333102415620286 http://journals.sagepub.com/doi/abs/10.1177/0333102415620286?journalCode=cepa#articleCitationDownloadContainer

Alexandre C, Latremoliere A, Ferreira A, et al. Decreased alertness due to sleep loss increases pain sensitivity in mice. Nature Medicine May 2017;23:768-74. Doi: 10.1038/nm.4329 https://www.nature.com/articles/nm.4329

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