Do you reach for your smartphone when you get in bed or fall asleep with the TV on? You’re not alone. Ninety percent of Americans use an electronic device in their bedroom within 1 hour of bedtime.1 Using electronics before or in bed is a popular practice. Unfortunately, it’s also an unhealthy one.
How blue light affects your sleep
Our sleep-wake cycles run on a 24-hour schedule that roughly follows the patterns of the sun. That’s why scientists call them our circadian rhythms (in Latin, “circadian” translates to “about day” ). We get sleepy in the evening after sunset and wake up in the morning with sunrise.
However, ever since Benjamin Franklin discovered electricity, humans have been exposed to increasing amounts of artificial light (3) after sunset. Any kind of artificial light can impact our circadian rhythm, but blue light is the most powerful.
When our eyes perceive blue light, our brain responds by increasing our energy levels, heart rate, and body temperature.4 As a result, we feel alert and focused.5 During the day, that’s great. It becomes a problem during the evening, when our brains need to start winding down for sleep. Continued exposure to blue light at night suppresses our body’s release of melatonin,6 the so-called “sleep hormone.” Our brain gets tricked into thinking it’s still daytime, so we stay awake instead of getting sleepy.
Too much exposure to blue light can disrupt your circadian rhythms and increase your risk of experiencing negative health consequences,7 including depression, sleep disruption and metabolic disorders. It’s important to be aware of sources of blue light in your life and find ways to reduce your risk.
Blue light can be found in:
- Fluorescent and LED lights
- Tablets and e-readers
- Computer screens
- Video game consoles
Ready for more restful sleep? Start with these tips for reducing your exposure to blue light.
1. Turn off the electronics at night
This is the easiest and most effective way to reduce your nighttime exposure to blue light. Simply turn off or dim unnecessary lights or devices 2-3 hours before sleeping.
2. There’s an app for that
If using your electronics before bed is non-negotiable, try one of several apps available for smartphones or computers that reduce blue-light emissions.
3. Change up your environment
Dim or turn-off light sources in your bedroom. If that is not possible, try using an eye mask to block them out.
With a few minor changes, reducing your exposure to blue light can be achieved relatively quickly. Say goodnight to your electronics, and treat yourself to better sleep.
For more information on all things sleep, please visit SleepFoundation.org.
1 Gradisar, M., Wolfson, A. R., Harvey, A. G., Hale, L., Rosenberg, R., & Czeisler, C. A. (2013). The sleep and technology use of Americans: findings from the National Sleep Foundation’s 2011 Sleep in America poll. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, 9(12), 1291–1299. https://doi.org/10.5664/jcsm.3272
2 Merriam-Webster. (n.d.). Circadian. In Merriam-Webster.com dictionary. Retrieved February 2, 2021, from https://www.merriam-webster.com/dictionary/circadian
3 Wright, K. P., Jr, McHill, A. W., Birks, B. R., Griffin, B. R., Rusterholz, T., & Chinoy, E. D. (2013). Entrainment of the human circadian clock to the natural light-dark cycle. Current biology : CB, 23(16), 1554–1558. https://doi.org/10.1016/j.cub.2013.06.039
4 Wahl, S., Engelhardt, M., Schaupp, P., Lappe, C., & Ivanov, I. V. (2019). The inner clock-Blue light sets the human rhythm. Journal of biophotonics, 12(12), e201900102. https://doi.org/10.1002/jbio.201900102
5 Vandewalle, G., Maquet, P., & Dijk, D. J. (2009). Light as a modulator of cognitive brain function. Trends in cognitive sciences, 13(10), 429–438. https://doi.org/10.1016/j.tics.2009.07.004
6 Lockley, S. W., Brainard, G. C., & Czeisler, C. A. (2003). High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light. The Journal of clinical endocrinology and metabolism, 88(9), 4502–4505. https://doi.org/10.1210/jc.2003-030570
7 Jagannath, A., Taylor, L., Wakaf, Z., Vasudevan, S. R., & Foster, R. G. (2017). The genetics of circadian rhythms, sleep and health. Human molecular genetics, 26(R2), R128–R138. https://doi.org/10.1093/hmg/ddx240