Powering Down: How “Blue Light” from Devices Affects Your Sleep

(Article by Surya Konkimalla. Illustration by Carolyn Duan)

Time: 10:30 PM. The blue and gray chat bubbles of Facebook pop up repeatedly on your phone. Your fingers flitter about the phone’s keyboard, pressing “enter” every few seconds. The “ding” sounds are nonstop.

Time: 11:00 PM. Your friend continues to send messages and your urge to reply is irresistible. You know you have to put your phone away for the night, but you simply cannot.

Time: 11:30 PM. Your phone runs out of battery and dies, forcing you to put it down and go to sleep.

We have all had an experience like this before, whether we like to admit or not. It is late at night, you have finished all of your homework, and are ready to go to bed. However, you get the feeling that you just have to peek at your phone one last time, to check your messages or to watch one more YouTube video. Then those few minutes you meant to spend turn into a hour, and you end up going to bed much later than you could have.

But there’s an even bigger problem – now your eyes burn from looking at a bright screen for too long, and you have trouble falling asleep. What is really happening when you stare into the radiance of your device?


The Power of Blue Light

It may not seem like it matters, but that extra time you are spending on your device right before bed is harming your sleep – not only the quantity, but the quality as well. This is due to the “blue light” that your device is emitting, whether it is a phone, laptop, or television. Blue light has a variety of natural and artificial sources – it is present everywhere from the Earth’s sky to fluorescent bulbs.

However, in this era of technology, blue light has many new sources that surround us for almost the whole day: our devices. It is likely that your devices use LED backlighting, a technology that improves visual media quality. The device screen may be brighter and clearer, but this enhancement comes with a cost, as LEDs are a major source of blue light.  

Blue light does have its benefits – it heightens alertness and improves memory. So our bodies certainly need blue light, but only during certain times of the day. As you may guess, the middle of the night, right before going to bed, is not one of these times.

What makes blue light so hazardous is its ability to lower melatonin, the hormone that establishes your “body clock”, formally known as your circadian rhythm. Your circadian rhythm is the cycle of your body’s daily routines, such as waking up, eating, and sleeping. Your body follows this “clock”, so it knows what time each of these activities should take place.

If your device usage falls within an hour of your bedtime, it is likely that your melatonin production is being suppressed, disrupting your circadian rhythm and making it more difficult to fall asleep.

How exactly does this work? During the duration of the day, your melatonin levels are relatively low. As your day winds down, and your bedtime approaches, more melatonin is produced. In the middle of the night, when you are asleep, your body’s melatonin quantity reaches its maximum.

Of course, melatonin levels reflect your individual circadian rhythm – each and every one is unique. It is still important, however, to allow your body to naturally produce melatonin based on your sleeping patterns. If you are being exposed to blue light before bed, this cannot happen.

When your body has lower levels of melatonin than it should, your circadian rhythm causes your body to feel the need to stay awake longer. Until your melatonin levels return to normal, your circadian rhythm will not be restored, and your sleeping time will be delayed.


Defeating the Blue Light Menace

Unfortunately, the solution is not as simple as turning off your device a few minutes earlier than usual. For many MVHS students, nightly screen time is a necessity for relaxing. “I spend about an hour with devices before bed,” said junior Justin Yee. “Usually, I check social media on my phone, or watch YouTube videos on my laptop”.

For the average, sleep-deprived MVHS student, every minute of rest is invaluable. With device overuse delaying their bedtime, not only is their quantity of sleep affected, but their quality of sleep is harmed as well, through prolonged exposure to blue light.

Students like junior Noah Tsou know that there are solutions. Tsou uses f.lux, an app that lowers the blue light that his laptop screen emits. The app will adjust the device display so that it displays “warmer” colors, substituting blue light with red and orange light. The idea is that at night, your device screen will emit light that is similar to the lighting inside your room. That way, when you’re using your device at night, you will no longer feel like you’re staring into the Sun.

The app turns on after a time set by the user, which is 7 PM in Tsou’s case. The device display will change accordingly until the next morning. However, without blue light, the screen will look different as a result. Tsou was able to solve this problem with an additional browser extension, which removes any visual artifacts, errors that affect pixel colors and cause media to be displayed incorrectly. Now that the effects of the app are minimized, he can enjoy YouTube videos at night.

After using it for seven months, Tsou says the difference is remarkable. Not only is his eyesight no longer strained by the excessive blue light, but he is able to fall asleep more easily as well. “Whenever I turn off the app, the screen becomes so bright it is hard to look at – it has become such an important part of my daily life because of how effective it is,” Tsou said. He feels the app is extremely useful and would definitely recommend it to other students.

Many of us, like Yee and Tsou, simply want some time to unwind after a tiring, stressful day. Using social media or watching YouTube videos offers a way to destress, but with a cost. Rather than being exposed to blue light and harming your sleep patterns, it would be better to avoid technology within an hour of your bedtime. Or, if absolutely necessary, an app like f.lux can help – as long as you don’t mind your screen looking a bit different.