Is blue light ruining your sleep?

Post by Emily White 

An old Irish proverb once said, "a good laugh and a long sleep are the best cures in the doctor's book” and this could not be truer. Sleep is key for optimal health, just as diet and exercise are. A lack of quality sleep can contribute to many health problems, such as heart disease, diabetes and depression (1). The problem with people today is that not only are we a lot 'busier' meaning we make less time for sleep, the sleep that we are managing to have is of a much lower quality then in the past. In the past, the sun was the main source of light and so as darkness came, so did sleep. Nowadays, nighttime does not necessarily mean darkness. Technology has enabled us to remain illuminated after dark but at what cost to our circadian rhythm?

As darkness falls, the secretion of the hormone melatonin is increased. This hormone is basically a signal to our bodies that it is time for bed and causes us to feel tired. Blue light, whether it is from a laptop or the sun, inhibits melatonin production, which in turn boosts attention and reaction times. Whilst this is great during the day, at night it can throw our circadian rhythm out of whack, causing our sleep quality to suffer (2).

A study was conducted recently that revealed 90% of Americans used electronics within 1 hour before bedtime. This shows just how important this is and could in fact explain why insomnia and sleep deprivation is on the rise worldwide (3). 

Many health practitioners recommend reading every night before bed to help fall asleep and to improve the quality of the sleep. Whilst in theory this is a greatly effective technique, many people are use a light emitting E-book to read instead of reading from a standard paperback. The problem with reading from an e-book is that the light emitted from the screen is shown to have a hugely detrimental affect on sleep duration and quality. Studies have showed that the use of these devices before bed increases the time it takes to fall asleep, delays the circadian clock, suppresses melatonin, has a negative impact on REM sleep and increases the feeling of tiredness the following day. Blue light increases alertness and so therefore whilst we may be getting into bed to relax and unwind- we could infact me doing the complete opposite (2).

To lessen the impact on sleep, putting down the E-book and picking up a paperback can do wonders. Also it is important to limit the use of electronics in the hours leading up to bedtime and to dim the lights to ensure you get some quality z's. If shutting the laptop screen late at night is not an option for you then downloading 'f.lux' on your device is a great option. 'F.lux' controls the type of light your laptop emits, depending on the time of day. This means in the evenings the amount of blue light is greatly decreased and this will significantly improve your sleep. 
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​1. Cappuccio, F. P., Cooper, D., D'Elia, L., Strazzullo, P., & Miller, M. A. (2011). Sleep duration predicts cardiovascular outcomes: a systematic review and meta-analysis of prospective studies.

2. Chellappa, S. L., Steiner, R., Oelhafen, P., Lang, D., Götz, T., Krebs, J., & Cajochen, C. (2013). Acute exposure to evening blue-enriched light impacts on human sleep. Journal of Sleep Research, 22(5), 573-580. doi: 10.1111/jsr.12050

3. Henriksen, T. E. G., Skrede, S., Fasmer, O. B., Hamre, B., Grønli, J., & Lund, A. (2014). Blocking blue light during mania – markedly increased regularity of sleep and rapid improvement of symptoms: a case report. Bipolar Disorders, 16(8), 894-898. doi: 10.1111/bdi.12265