Here’s How Blue Light Affects Sleep

We receive free products to review and participate in affiliate programs. See our disclosure page for more information.

It’s becoming common knowledge that limiting screen time before bed can help a person sleep better. The reasoning behind that? Studies have shown that the blue and white light emitted by many electronic prevents the brain from releasing melatonin, a hormone that tells the body when to go to sleep.

So if a person doesn’t have enough melatonin, he or she may have trouble falling — and staying — asleep. Thus, too much exposure to blue light can throw one’s circadian rhythms out of whack and affect the ability to rest.

Minerva Studio/Shutterstock

“We have known for quite awhile now that light is the most powerful cue for shifting the phase or resetting the time of the circadian clock,” Harvard University neuroscientist Anne-Marie Chang told Scientific American in 2015. “Recent studies have shown that short-wavelength [blue] light has a greater effect on phase shifting the circadian clock and on melatonin suppression.”

A new study has further clarified that light exposure can harm one’s sleep, and offered a potential solution. For a paper published recently in the medical journal Physiology and Behavior, researchers from Brigham and Women’s Hospital observed sixteen healthy participants over four days in an inpatient setting. The participants were exposed to various types of light, and their melatonin suppression, auditory reaction times, sleep time, and reported sleepiness were measured.

“The study shows that designing lighting to selectively inhibit the right wavelengths can substantially reduce the circadian disruption caused by exposure to light before bed,” researcher Steven Lockley, PhD of the Division of Sleep and Circadian Disorders at Brigham and Women’s Hospital, said in a press release.

So, how can people prevent blue light from affecting their sleep? One option is custom lighting, as recommended by the researchers behind this study.

Wattanachon Kongthon/Shutterstock

Experts also recommend staying away from screens for a couple of hours before bedtime — and sleep disorders specialist Dr. Harneet Walia at the Cleveland Clinic explains that “exposure to blue light can affect your internal body clock and throw off your circadian rhythm. This rhythm is in tune to light and dark. It’s why you feel more tired at night when the sun starts to set and why you feel more energized in the morning when it’s light.”

And soon, cosmetics may be able to help, too. Former supermodel Cindy Crawford just released a new product available exclusively at ULTA — the Meaningful Beauty Environmental Protecting Moisturizer Broad Spectrum SPF30 Sunscreen ($65) — that claims to battle the blue light emitted by electronics.


Featured image: Marcos Mesa Sam Wordley/Shuttershock

Joe Auer

Joe Auer

Joe Auer is the editor of Mattress Clarity. He mainly focuses on mattress reviews and oversees the content across the site. He likes things simple and takes a straightforward, objective approach to his reviews. Joe has personally tested nearly 250 mattresses and always recommends people do their research before buying a new bed. He has been testing mattresses for over 5 years now, so he knows a thing or two when it comes to mattress selection. He has been cited as an authority in the industry by a number of large publications. When he isn't testing sleep products, he enjoys working out, reading both fiction and non-fiction, and playing classical piano. He enjoys traveling as well, and not just to test out hotel mattresses! Joe has an undergraduate degree from Wake Forest University and an MBA from Columbia University.


Can’t keep up with all things sleep? Our email newsletters gives you the latest on upcoming deals, giveaways, and sleep health articles.