How to Reduce the Impact of Blue Light on Your Sleep Pattern
Before LED screens or artificial bulbs, our sleeping patterns (or circadian rhythms) were determined by sunlight. Now, in our digital age, a number of technological factors impact on our sleep — we fall asleep in front screens, check work-emails from bed, and surf the Internet into the early hours of the morning. While technology can be useful, blue light emitted from digital screens can disrupt the body’s internal biological clock, having a negative impact on our sleep hygiene. To help you understand how to reduce the impacts of blue light, we’ll take a look at exactly what blue light is and how it affects your sleep.
What is blue light?
Sunlight, or ‘white light’, is comprised of red, orange, yellow, green, and blue light rays — and myriad shades of each colour. Light rays with short wavelengths contain more energy, while those with relatively long wavelengths have less energy. This means that rays on the ‘red’ end of the spectrum have longer wavelengths and, therefore, less energy, and rays on the ‘blue’ end of the spectrum have shorter wavelengths and more energy. Generally speaking, blue light is defined as having a wavelength between 380nm and 500nm, making it one of the shortest, highest-energy wavelengths.
Natural vs. artificial blue light: what’s the difference?
Blue light is everywhere. Primarily, the sun emits an abundance of it. In fact, these wavelengths are responsible for giving the sky its blue appearance. More importantly, your body uses blue light to regulate its 24-hour internal clock, otherwise known as your circadian rhythm. This is because blue light energises the body, elevating mood, increasing alertness and increasing reaction times.i Beyond bolstering your mood and helping you feel invigorated during the day, it also helps to prepare the body for sleep at night.ii
However, not all blue light is created equally. Prolonged exposure to artificial sources of blue light from electronic devices, like laptops, smartphones, and TVs, as well as fluorescent bulbs and LED lights can have a negative impact on our overall health. Though these gadgets only produce a fraction of the energy generated by natural blue light, the proximity to our faces and amount of time spent using digital devices can have repercussions, especially where our sleep is concerned.
How does blue light affect sleep?
Our bodies rely on light and darkness cues to regulate sleep. Light signals activity, while darkness signals rest. Melatonin, the hormone responsible for inducing sleep, is often called the ‘darkness hormone’ because it is triggered by dim or dark lighting. Your brain begins releasing this chemical a few hours before you sleep, peaking in the middle of the night.
However, exposure to man-made blue light in the evening can disrupt your natural biological clock, inhibiting your body’s production of melatonin and reducing both the quality and quantity of your sleep.iii Science consistently points to blue-light as a key contributor to poor sleep hygiene. In a study published in the Journal of Clinical Endocrinology & Metabolism, researchers found that a brightly lit room at night suppressed melatonin by 85%, compared to a dimly lit environment.iv
How to reduce the impact of blue light on sleep patterns
While limiting the use of technology is not always an option, there are a number of practical steps that you can take to reduce the impact of blue light online.
Install blue light blocking software on laptops, turn all e-devices onto ‘night-mode’ and reduce the brightness on screens
Set yourself a technology curfew — refrain from using technology in the 90-minutes before bed
Remove all screens from your bedroom — use an old-fashioned alarm clock instead of your phone to wake you up in the morning
Turn all bright lights down in the evening — soft lamps and candles are great alternatives
Use dim red lights for night-lights — red light is less able to shift the circadian rhythm and suppress melatonin.
Embrace morning sunlight — this will support your internal clock, helping you feel alert and energised during the day and promoting sleep at night
Invest in a pair of blue-blocking amber glasses and wear them in the evenings. Some would argue that blue light glasses are the most effective way to filter out harmful blue light rays. Research shows that wearing blue light blocking glasses, even while using electronic devices or sitting in a lit room, doesn’t inhibit melatonin production.v
Want to discover more even ways to improve your sleep hygiene? Feel free to browse the rest of our sleep health hub for lots more articles and advice. If you want to delve further into the effects of blue light on eye health, visit our vision hub.
ScienceDaily. (2019). Blue light may fight fatigue around the clock. Available online: https://www.sciencedaily.com/releases/2014/02/140203191841.htm
Münch. M., Linhart. F., Borisuit. A., Jaeggi. S. & Scartezzini. J. (2012). Effects of prior light exposure on early evening performance, subjective sleepiness, and hormonal secretion. Behavioral Neuroscience. 126(1), 196-203.
Gooley. J.J., Chamberlain. K., Smith. K.A., Khalsa. S.B., Rajaratnam. S.M., Van Reen. E., Lockley. S. (2011). Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans. The Journal of clinical endocrinology and metabolism. 96(3), E463–E472.
Gooley. J., Chamberlain. K., Smith. K., Khalsa. S., Rajaratnam. S., Van Reen. E., Zeitzer. J., Czeisler. C. & Lockley. S. (2011). Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans. Endocrinology. 152(2), 742-742.
Wood. B., Rea. M., Plitnick. B. & Figueiro. M. (2011). Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression. Applied Ergonomics. 44(2), 237-240.
Olivia Salter has always been an avid health nut. After graduating from the University of Bristol, she began working for a nutritional consultancy where she discovered her passion for all things wellness-related. There, she executed much of the company’s content marketing strategy and found her niche in health writing, publishing articles in Women’s Health, Mind Body Green, Thrive and Psychologies.