There are five primary factors that impair sleep, and Light, including blue light, is at the top of the list. The other four include noise, heat, alcohol, and caffeine.

Light helps regulate the human biological clock (1), notably through melatonin, a hormone that signals your body that it is time to sleep. Blue light — which is produced by the sun but also by the screens of TV sets, computers, and smartphones — disrupts your production of melatonin (2). For that reason, it is important you avoid blue lights during the two hours before bedtime.

A Bluelight Filter and Sleep

Yes, if it emits blue light, even the small screen of a smartphone can make it harder for you to fall asleep. A small, randomized crossover trial examining the impact of smartphones with and without blue light found that, even though smartphones with blue light did not significantly affect serum melatonin levels, they still reduced sleepiness (3). So if you must use electronics before bedtime, consider installing a program that gradually reduces blue light from the screen after sunset. Fortunately, more and more devices come with such a program preinstalled (e.g., Night Shift on iPhones and Macs). I use an app on my Samsung called Bluelight Filter and think it is very effective and allows me to adjust the percentage of blue light.

Bluelight Blocker Glasses and Sleep

But what if you can’t easily adjust the color balance of your screen? Or you must work on your laptop late into the night? Or if the blue-light source is a lighting fixture in a room you share with other people? In such instances, consider wearing blue-light-blocking glasses a couple of hours before bedtime (4). Remember, however, that though blue light is the main offender, you should avoid any bright lights in the hours leading to sleep (5).

If you are interested in purchasing blue light blocker glasses, we have a partnership with Pixel eyewear. Get $5 off your order when you use the code: HEALTHYGOODS5

Pixel’s selection of glasses is beautiful, and they offer a money-back guarantee. If you are not 100% satisfied, you can return or exchange the glasses within 30 days. 

Light Sensitivity and Sleep

Finally, please know even when you’re already in the land of dreams, light can still impair the quality of your sleep. If you live in an area where light pollution is a concern, consider completing your dark therapy by installing blackout curtains or using a sleep mask.

To fall asleep faster, avoid bright lights and blue lights within the two hours before bedtime; if necessary, use blue-light blocking glasses or a device application/program that reduces the blue light from the screen of your computer, tablet, or phone. To sleep better, make your bedroom dark; if you can’t, consider using a sleep mask.

In Health and Happiness,

Kelly Harrington, MS, RDN

Registered Dietitian Nutritionist for Healthy Goods

References:

1. Tosinj G, Ferguson I, Tsubota K. Effects of blue light on the circadian system and eye physiology. Mol Vis. (2016)
2. Bedrosian TA, Nelson RJ. Timing of light exposure affects mood and brain circuits. Transl Psychiatry. (2017)
3. Heo JY, et al. Effects of smartphone use with and without blue light at night in healthy adults: A randomized, double-blind, cross-over, placebo-controlled comparison. J Psychiatr Res. (2017)
4. Esaki Y, et al. Wearing blue light-blocking glasses in the evening advances circadian rhythms in the patients with delayed sleep phase disorder: An open-label trial. Chronobiol Int. (2016)
5. Keldon AC, Phillips AJ, Dijk DJ. The effects of self-selected light-dark cycles and social constraints on human sleep and circadian timing: a modeling approach. Sci Rep. (2017)