Does Blue Light Really Affect Your Sleep?

by Nate Widom

I’ll admit it. Sometimes I crawl into bed with my iPad in hand and tell myself I can scroll through Tik Tok for fifteen minutes. Then, as I peruse my feed, the sense of time leaves my head and I find a random Tik Tok of a creator with a bright smile calling me out to my face saying that I need to close the app and get some sleep. I then check the time and realize what felt like fifteen minutes was closer to two hours.

Clearly, this before-bed ritual is not the healthiest. When spending those two hours on an electronic device, I set myself up for a poor night’s rest. And I’m not the only one who uses an electronic device before bedtime. The Sleep Foundation found in a 2011 poll that nine out of ten Americans use a technological device before bed. The study also reported that people who use more interactive devices like laptops and video games had more unrefreshing and delayed sleep than those who use “passive” gadgets like TVs.

Many contribute their adverse sleep to blue light – a light emitted from the screens of many electronic devices. But, according to the Sleep Foundation, while blue light is present in many LEDs, fluorescent lights, and electronic devices, it’s also produced by the sun– and that’s also where we receive most of our blue light exposure.

However, exposure to blue light during daylight hours isn’t problematic. The foundation states that blue light stimulates areas within the brain that make us feel alert and attentive, thus elevating our body temperature and heart rate. It also prepares us for a better night’s sleep as it tunes our circadian rhythms during the day and suppresses the body’s release of melatonin– the hormone associated with controlling the sleep-wake cycle.

After reading that, it’s clear why being exposed to blue light right before bedtime is an issue. Essentially, at night we are exposing ourselves to light that is naturally occurring in the day. Unfortunately, this tricks our bodies into thinking it’s daytime when we are supposed to be winding down for the night. Ultimately, this creates a situation where falling asleep takes longer, and less sleep can cause many negative effects.

Besides feeling tired throughout the day, Healthline reports that sleep deprivation can cause memory and concentration issues, mood changes, weakened immunity, a low sex drive, and increased risk for diabetes, accidents, high blood pressure, and weight gain. A 2010 review study from the UK’s University of Warwick even found that sleeping too little (and too much) at night led to a greater risk of death!

But if you’re like me, turning off electronics once the sun goes down is difficult. For those of us wanting to use our electronics as much as possible before bed, some options may help mitigate the effects of blue light.

One of those options includes using different lighting in your home. The Sleep Foundation recommends using warm-toned incandescent bulbs or dimmers instead of the LED and fluorescent variety. If you’re unable to switch to different bulbs, dimming the lights in your home may make a slight difference in your sleep.

However, the relationship between dimming lights in the home and sleep seems to be minimal. In a Rush University Medical Center study in Chicago, researchers examined if the brightness of lights in the participant’s home can shift their circadian phase. Participants dimmed their lights down to ~3 lux four hours before bedtime and repeated the process the following week with lights brightened to ~65 lux. The researchers concluded that during the weeks with bright light, the participants had an altered circadian rhythm but went to bed on average only fourteen minutes later.

There is possibly good news for those who have insomnia and wish to use blue light-blocking glasses. A 2018 Columbia University study examined the sleep quality of fourteen insomnia patients wearing amber-colored blue light-blocking glasses compared to clear glasses before bedtime. After seven nights, the researchers found that the patients who wore amber glasses had a significantly delayed wake-time and higher overall quality of sleep and total sleep time. But for those who don’t experience insomnia, the effectiveness of blue light-blocking glasses is debated. The Executive Editor of the Harvard Heart Letter, Julie Corliss, spoke to Dr. Steven Lockley, a neuroscientist at Brigham and Women’s Hospital. According to Lockley, most blue light filtering glasses lack standardization throughout the industry, and many studies lack critical details to conclude their effectiveness. A 2017 review study also came to a similar conclusion. The researchers concluded that they found a lack of evidence supporting the lenses “for the general population to improve visual performance or sleep quality, alleviate eye fatigue, or conserve macular health.”

From personal experience, I don’t find any significant difference in sleep between when I wear and don’t wear blue light-blocking glasses. At the very least, I found the amber-colored filter successfully altered and dimmed all the lights in my room, which is much easier on my eyes!

Like blue light-blocking glasses, utilizing night mode on applicable electronic devices is also thought to help. For example, according to Apple, the night shift feature on their products automatically adjusts a device’s display to be warmer in color, hence making it “easier on your eyes.” This was precisely what I experienced when wearing blue light-blocking glasses before bed!

However, many studies also did not find night mode to be effective. For instance, a BYU and Cincinnati Children’s Hospital Medical Center study compared the sleep between many 18–24-year-old subjects. One group used their phone before bed with the night shift enabled, another group used the standard display, and a different group didn’t use their phones before bed. The researchers found that night shift wasn’t “superior to using your phone without night shift or even using no phone at all.”

Even more interesting, the researchers found the group that didn’t use a phone before bedtime experienced “superior” sleep quality compared to the other participants. The study concluded that these results weren’t caused by blue light but rather the cognitive stimulation that comes with using a phone.

“Researchers found the group that didn’t use a phone before bedtime experienced “superior” sleep quality compared to the other participants.”

As you can see, current evidence is lacking as to whether blocking blue light can positively impact sleep in any significant way for the general population. Still, doctors and sleep experts currently recommend that you turn off electronics entirely before bed, no matter how hard that may be.

In addition to making your bedroom “technology-free,” the Sleep Foundation recommends a bedtime routine. They write, “the hour before bed should consist of relaxing activities that don’t involve devices with screens.” Furthermore, they recommend decreasing your daytime electronic use, meditating, reading a book, and rewarding yourself when you successfully sleep without using technology.

With a proper routine and mental training, it’s possible to put your electronics down and get a better night’s rest!

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