In a world increasingly dependent on technology, bright screens are more commonly part of our everyday life. These screens range broadly in size and purpose: televisions, computers, tablets, smartphones, e-books, and even wearable tech.
How does thisartificial light,especially when viewed at night, potentially impact our sleep? Learn how light at night affects our body’scircadian rhythmand whether it might contribute toinsomniaand difficulty awakening. In addition, consider ways to reduce light exposure and counteract its effects.
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How Modern Technology Changed Life and Sleep
It is hard to imagine a time before artificial light existed. It is such an integral part of our lives that we consider ourselves deeply inconvenienced when we lose power in a storm. Think back to what life was like before modern technology, such as computers and televisions, before light bulbs, and even before electricity.
Primitive societies and people were highly dependent on the natural availability of light. The sun ruled life. It is no surprise that it was worshiped in ancient Egypt. When artificial light became possible, things dramatically changed.
The Influence of Light on the Body’s Functions
All life on Earth has developed patterns of activity dependent on the timing of day and night. When isolated from the natural environment, innate circadian patterns will be revealed.As an example, most humans have an internal clock that runs just about 24 hours in length (24 hours and 11 minutes, plus or minus 16 minutes, to be exact).However, exposure tolightresets our clock, andprofoundly affects the timing of sleep and wakefulness, metabolism (e.g. insulin/glucose), and hormone (e.g. melatonin, cortisol) release.
Due to the length of our internal clock, our bodies have a natural tendency towards delay in the timing of our sleep. This means that we always find it easier to go to bed later and wake later. Have you ever noticed how easy it is to stay up another 15 minutes but how difficult it is to wake just 15 minutes earlier?
Morning sunlighthas a key influence on life’s functions. The composition of morning light resets our internal clock and promotes wakefulness and ends sleep.It can help shift the desire for sleep slightly earlier in the evening. In the winter, when sunlight comes later, we may want to sleep in, or suffer from symptoms called winter depression.
Does a Full Moon Affect Sleep?
How Artificial Light at Night Impacts Sleep
Artificial light can also impact our circadian rhythm.Unfortunately, artificiallight at nightcan negatively affect the timing of our sleep, and can shift our desire for sleep later into the evening.This can result in difficulty falling asleep, as occurs withinsomnia. Night owls, or those with delayed sleep phase syndrome, may be especially susceptible.
Not everyone is sensitive to these effects. If you are especially sleepy, perhaps due to inadequate total sleep time or poor sleep quality, you are unlikely to be impacted.
There are several important factors to consider:
Tips for Getting Better Sleep
Therefore, it is very important to turn down the lights at night, especially preceding your bedtime. Ideally, light at night should be dim (~3 lux), containing red, yellow, or orange wavelengths, and efforts should be made to block blue light from devices.Some people may need to avoid excessive artificial light exposure for the 1-2 hours before going to bed.This means turning off the phone, powering down the computer, and avoiding light from tablets, e-books, and other sources.
Instead, try to stick to low-tech options. Listen to relaxing music, sip a warm cup of tea, or try meditation. By reducing and eliminating your exposure to light at night, you may find that you are able to sleep better. If you continue to struggle, speak with a sleep doctor about additional treatment options.
13 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Effects of light on circadian rhythms.Czeisler CA, Duffy JF, Shanahan TL, et al.Stability, precision, and near-24-hour period of the human circadian pacemaker.Science.1999;284(5423):2177-2181. doi:10.1126/science.284.5423.2177Brennan R, Jan J. Lyons C.Light, dark, and melatonin: Emerging evidence for the importance of melatonin in ocular physiology.Eye. 2007;21, 901–908. doi:10.1038/sj.eye.6702597Cheung IN, Zee PC, Shalman D, Malkani RG, Kang J, Reid KJ.Morning and evening blue-enriched light exposure alters metabolic function in normal weight adults. Bartell PA, ed.PLoS ONE. 2016;11(5). doi:10.1371/journal.pone.0155601Kozaki T, Kubokawa A, Taketomi R, Hatae K.Light-induced melatonin suppression at night after exposure to different wavelength composition of morning light.Neuroscience Letters. 2016;616:1-4. doi:10.1016/j.neulet.2015.12.063Blume C, Garbazza C, Spitschan M.Effects of light on human circadian rhythms, sleep and mood.Somnologie. 2019;23(3):147-156. doi:10.1007/s11818-019-00215-xPacheko D.How to fix your circadian rhythm: 6 easy steps. Sleep Foundation.Cleveland Clinic.Circadian rhythm sleep disorders.Golden RN, Gaynes BN, Ekstrom RD, et al.The efficacy of light therapy in the treatment of mood disorders: A review and meta-analysis of the evidence.AJP. 2005;162(4):656-662. doi:10.1176/appi.ajp.162.4.656Finio B.Science with a smartphone: Measure light with lux.Scientific American. Published October 3, 2019.Pacheco D.How electronics affect sleep. Sleep Foundation.Cleveland Clinic.Do blue light glasses work?Gooley JJ, Chamberlain K, Smith KA, et al.Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans.The Journal of Clinical Endocrinology & Metabolism. 2011;96(3):E463-E472. doi:10.1210/jc.2010-2098
13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Effects of light on circadian rhythms.Czeisler CA, Duffy JF, Shanahan TL, et al.Stability, precision, and near-24-hour period of the human circadian pacemaker.Science.1999;284(5423):2177-2181. doi:10.1126/science.284.5423.2177Brennan R, Jan J. Lyons C.Light, dark, and melatonin: Emerging evidence for the importance of melatonin in ocular physiology.Eye. 2007;21, 901–908. doi:10.1038/sj.eye.6702597Cheung IN, Zee PC, Shalman D, Malkani RG, Kang J, Reid KJ.Morning and evening blue-enriched light exposure alters metabolic function in normal weight adults. Bartell PA, ed.PLoS ONE. 2016;11(5). doi:10.1371/journal.pone.0155601Kozaki T, Kubokawa A, Taketomi R, Hatae K.Light-induced melatonin suppression at night after exposure to different wavelength composition of morning light.Neuroscience Letters. 2016;616:1-4. doi:10.1016/j.neulet.2015.12.063Blume C, Garbazza C, Spitschan M.Effects of light on human circadian rhythms, sleep and mood.Somnologie. 2019;23(3):147-156. doi:10.1007/s11818-019-00215-xPacheko D.How to fix your circadian rhythm: 6 easy steps. Sleep Foundation.Cleveland Clinic.Circadian rhythm sleep disorders.Golden RN, Gaynes BN, Ekstrom RD, et al.The efficacy of light therapy in the treatment of mood disorders: A review and meta-analysis of the evidence.AJP. 2005;162(4):656-662. doi:10.1176/appi.ajp.162.4.656Finio B.Science with a smartphone: Measure light with lux.Scientific American. Published October 3, 2019.Pacheco D.How electronics affect sleep. Sleep Foundation.Cleveland Clinic.Do blue light glasses work?Gooley JJ, Chamberlain K, Smith KA, et al.Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans.The Journal of Clinical Endocrinology & Metabolism. 2011;96(3):E463-E472. doi:10.1210/jc.2010-2098
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Centers for Disease Control and Prevention.Effects of light on circadian rhythms.Czeisler CA, Duffy JF, Shanahan TL, et al.Stability, precision, and near-24-hour period of the human circadian pacemaker.Science.1999;284(5423):2177-2181. doi:10.1126/science.284.5423.2177Brennan R, Jan J. Lyons C.Light, dark, and melatonin: Emerging evidence for the importance of melatonin in ocular physiology.Eye. 2007;21, 901–908. doi:10.1038/sj.eye.6702597Cheung IN, Zee PC, Shalman D, Malkani RG, Kang J, Reid KJ.Morning and evening blue-enriched light exposure alters metabolic function in normal weight adults. Bartell PA, ed.PLoS ONE. 2016;11(5). doi:10.1371/journal.pone.0155601Kozaki T, Kubokawa A, Taketomi R, Hatae K.Light-induced melatonin suppression at night after exposure to different wavelength composition of morning light.Neuroscience Letters. 2016;616:1-4. doi:10.1016/j.neulet.2015.12.063Blume C, Garbazza C, Spitschan M.Effects of light on human circadian rhythms, sleep and mood.Somnologie. 2019;23(3):147-156. doi:10.1007/s11818-019-00215-xPacheko D.How to fix your circadian rhythm: 6 easy steps. Sleep Foundation.Cleveland Clinic.Circadian rhythm sleep disorders.Golden RN, Gaynes BN, Ekstrom RD, et al.The efficacy of light therapy in the treatment of mood disorders: A review and meta-analysis of the evidence.AJP. 2005;162(4):656-662. doi:10.1176/appi.ajp.162.4.656Finio B.Science with a smartphone: Measure light with lux.Scientific American. Published October 3, 2019.Pacheco D.How electronics affect sleep. Sleep Foundation.Cleveland Clinic.Do blue light glasses work?Gooley JJ, Chamberlain K, Smith KA, et al.Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans.The Journal of Clinical Endocrinology & Metabolism. 2011;96(3):E463-E472. doi:10.1210/jc.2010-2098
Centers for Disease Control and Prevention.Effects of light on circadian rhythms.
Czeisler CA, Duffy JF, Shanahan TL, et al.Stability, precision, and near-24-hour period of the human circadian pacemaker.Science.1999;284(5423):2177-2181. doi:10.1126/science.284.5423.2177
Brennan R, Jan J. Lyons C.Light, dark, and melatonin: Emerging evidence for the importance of melatonin in ocular physiology.Eye. 2007;21, 901–908. doi:10.1038/sj.eye.6702597
Cheung IN, Zee PC, Shalman D, Malkani RG, Kang J, Reid KJ.Morning and evening blue-enriched light exposure alters metabolic function in normal weight adults. Bartell PA, ed.PLoS ONE. 2016;11(5). doi:10.1371/journal.pone.0155601
Kozaki T, Kubokawa A, Taketomi R, Hatae K.Light-induced melatonin suppression at night after exposure to different wavelength composition of morning light.Neuroscience Letters. 2016;616:1-4. doi:10.1016/j.neulet.2015.12.063
Blume C, Garbazza C, Spitschan M.Effects of light on human circadian rhythms, sleep and mood.Somnologie. 2019;23(3):147-156. doi:10.1007/s11818-019-00215-x
Pacheko D.How to fix your circadian rhythm: 6 easy steps. Sleep Foundation.
Cleveland Clinic.Circadian rhythm sleep disorders.
Golden RN, Gaynes BN, Ekstrom RD, et al.The efficacy of light therapy in the treatment of mood disorders: A review and meta-analysis of the evidence.AJP. 2005;162(4):656-662. doi:10.1176/appi.ajp.162.4.656
Finio B.Science with a smartphone: Measure light with lux.Scientific American. Published October 3, 2019.
Pacheco D.How electronics affect sleep. Sleep Foundation.
Cleveland Clinic.Do blue light glasses work?
Gooley JJ, Chamberlain K, Smith KA, et al.Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans.The Journal of Clinical Endocrinology & Metabolism. 2011;96(3):E463-E472. doi:10.1210/jc.2010-2098
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