The Impact Of Blue Light On Sleep

  • Ellie kerrodBSc Neuroscience - The University of Manchester, England

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Overview

Blue light has a specific wavelength that may interfere with circadian rhythms and disrupt sleeping patterns.1 Circadian rhythms are the internal body clock, and they are set to a 24-hour cycle regulating the sleep-wake cycle.2 Blue light is emitted from electronic devices, which explains why this concern has grown over the recent years as the use of electronic devices increases.1 Recently, there has been more and more research focusing on the effect of blue light, not only on sleep but also on other cognitive functions.1 Sleep is very important, and this is emphasised by the fact that it occupies approximately a third of the day.3 Although there is limited evidence so far, some research suggests that blue light may negatively impact sleep by preventing the secretion of melatonin, which is a sleep-promoting hormone.1 In theory, reducing blue light exposure during the day and, more importantly, before bed should improve sleep quality or not inhibit it.1 There are some easy tips you can try to reduce your blue light exposure and get a better night's sleep.1 These tips include turning off electronics a few hours before bed, using red or yellow-based lights, and sleeping with an eye mask.1 There are also natural biological processes that filter out blue light, which can be supported by eating a vitamin-rich diet or taking additional supplements.4 It is important to note that there is still little evidence on this topic, but there are no negative consequences of trying it to reduce blue light exposure, and it may help you.4

Blue light sources

Blue light is emitted from sunlight; however, it is also emitted from light-emitting diodes (LEDs) used in electronic devices. These artificial forms of blue light are in electronics such as phones, laptops, TVs, and tablets.4 Due to the increase in exposure to artificial blue light over the past decade, more questions are being asked about the long-term effects. Some studies suggest blue light may be harmful to our eyes, and preventive measures may be useful to help minimise the potential long-term side effects.4

How does blue light affect our eyes?

When eyes are exposed to light, a cascade of cornea, lens, and retina reactions are caused. These are all critical structures in the eye that enable healthy, functional eyesight.4 Some research suggests that repeated exposure to blue light can damage these important structures.4 In theory, this means that taking protective measures, such as wearing blue light glasses, may help reduce this damage. However, there is no evidence so far to conclude that wearing protective eyewear prevents eye-related diseases.4 It is thought that protective eyewear may reduce mild symptoms and provide some relief, but this is mostly based on anecdotal evidence.5

How blue light affects sleep

Electronics like phones, laptops, and TVs emit blue light, and research now suggests that blue light reduces melatonin secretion. This is important because high levels of melatonin promote sleep, and low levels promote wakefulness, a likely mechanism by which blue light negatively impacts sleep.1

However, there is still limited research on the impact of blue light on sleep. Some research implies that it isn’t the blue light that causes sleep problems but something else.

Is blue light always bad?

The simple answer is no; blue light isn’t always bad for you. Blue light has been reported to be beneficial in a few ways, aiding in cognitive functioning, alertness, and reaction time.1 It has also been proposed that blue light could enhance sporting performances.1

Who is affected?

Blue light affects everyone who is exposed to sunlight, electronic devices and artificial lighting, but those who are exposed to high levels may be at higher risk of disrupted sleeping patterns.1 These people include those who work with computers, have office jobs or use TVs, laptops, and smartphones extensively.1

Technological solutions

There are a few easy tips to minimise blue light exposure and help improve sleep. 

  • Dim setting on devices: On smartphones and other devices, some settings and apps can be turned on to reduce or eliminate the blue light that is being emitted from the device
  • Sleeping eye masks: To reduce the amount of blue light before bed, try sleeping with an eye mask to block the light
  • Changing lights: Try using yellow or reddish lighting instead of blue tone lights, especially at night
  • Turn off electronic devices before bed: Reducing screen time a few hours before bed may help you sleep better. Not only does it lower your blue light exposure, but it also helps with computer vision syndrome (CVS).  A condition that causes eye strain caused by electronic devices. Using these devices for long amounts of time can result in headaches, blurry vision, dry eyes, and neck pain
  • Blue light-blocking glasses: Although there is no significant evidence to support the effectiveness of blue light-blocking glasses in terms of improving sleep quality, there is no harm in trying them out. Some people find them to be helpful if they struggle to get a good night’s sleep

Alternative methods

The body has a natural process of filtering out blue light either from daylight or artificial sources; this is done by macular pigments, which are biological molecules that help filter light.4 Because these molecules occur naturally, they are found in food sources. Therefore, increasing your food intake of foods with high nutrient density may help enhance this filtering process.4 Furthermore, eating a balanced vitamin-dense diet can help enable adequate functioning of these processes. You could also consider using supplements to boost your vitamin intake; suggested supplements are Vitamin E, Vitamin C and Zinc.4

Summary

In recent years, the impact of blue light exposure on sleep and overall health has become a topic of interest for many people. Blue light is emitted naturally from daylight or electronic devices. Blue light is emitted from LEDs, which are found in electronic screens, including smartphones, tablets, computers, and TVs. The theory behind blue light negatively affecting sleep stems from its interaction with our circadian rhythms. The circadian rhythm is our internal body clock that is set to 24 hours and regulates our sleep-wake cycle. Blue light suppresses the release of melatonin, which is a sleep-promoting hormone that helps us fall and stay asleep. This is particularly concerning as any interference with our sleep may have a significant impact on our overall health. 

Sleep is extremely important in maintaining healthy and efficient functioning. To overcome the potential negative impacts of blue light, there are some solutions to minimise your exposure and improve your chances of getting a better night's sleep. This includes reducing screen time, reducing the use of electronics, having dim settings or apps on devices, and wearing sleeping eye masks. There are also blue-light glasses available which block blue light and, in theory, should help reduce exposure. However, there is limited evidence to support their effectiveness at the moment. They have been reported to provide mild relief and reduce some symptoms, but the evidence is mainly anecdotal. Anyone is susceptible to the effects of blue light; however, some people are more at risk. This includes people who spend more time on electronic devices. For example, people who work on a computer compared to someone who works outside an office. Overall, blue light may negatively impact our health and sleep, and more research is needed to investigate this. However, there is no harm in trying preventative measures and seeing if they work for you.

FAQs

What is blue light?

Blue light is a part of the visible light spectrum and is a part of sunlight, but it is also emitted by the LEDs in phones, tablets, laptops, and other devices.

Is blue light dangerous?

While there is evidence to suggest that excessive exposure to blue light can disrupt sleeping patterns and have many adverse effects, it is not inherently dangerous. The body has a natural filtration system to remove blue light and protect the eyes. Furthermore, there is contradictory evidence on whether or not blue light is harmful, but preventative measures can be taken just in case. 

How can I protect myself from blue light damage?

Blue light glasses have been suggested to be worn when working with computers or when using electronic devices extensively. However, their efficacy is debated. Wearing sleeping masks at night to block out blue light, using dimming apps or settings on your devices and avoiding LED lighting have all been suggested to protect eyes against blue light. Eating a balanced diet high in essential vitamins and/or taking supplements has been advised to promote eye health. Always consult a medical professional before taking any supplements. 

References

  1. Silvani MI, Werder R, Perret C. The influence of blue light on sleep, performance and wellbeing in young adults: A systematic review. Front Physiol [Internet]. 2022 Aug 16 [cited 2023 Sep 22];13:943108. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9424753/
  2. Farhud, Dariush, and Zahra Aryan. ‘Circadian Rhythm, Lifestyle and Health: A Narrative Review’. Iran J Public Health., vol. 47, no. 8, 2018, pp. 1068–76, Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6123576/.
  3. How sleep works - why is sleep important? | nhlbi, nih [Internet]. 2022 [cited 2023 Sep 22]. Available from: https://www.nhlbi.nih.gov/health/sleep/why-sleep-important
  4. Cougnard-Gregoire A, Merle BMJ, Aslam T, Seddon JM, Aknin I, Klaver CCW, et al. Blue light exposure: ocular hazards and prevention—a narrative review. Ophthalmol Ther [Internet]. 2023 Apr [cited 2023 Sep 28];12(2):755–88. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9938358/
  5. Bigalke JA, Greenlund IM, Nicevski JR, Carter JR. Effect of evening blue light blocking glasses on subjective and objective sleep in healthy adults: A randomized control trial. Sleep Health [Internet]. 2021 Aug 1 [cited 2023 Sep 28];7(4):485–90. Available from: https://www.sciencedirect.com/science/article/pii/S2352721821000127

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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Ellie Kerrod

BSc Neuroscience - The University of Manchester, England

I’m a Neuroscience BSc student studying at The University of Manchester, UK and have experience in medical writing. I am passionate about ensuing that everyone can assess accurate medical information and I am committed to bridging the gap between complex medical concepts and the public.

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