Blue Light Disrupts Sleep


In these pages, I often talk about the impact of sleep on your health.

It truly affects everything. From your immune system, to digestion, to the possibility of developing diseases like diabetes and cancer later in life—sleep is at the heart of it all.

That’s why it’s so important to make sure you get the proper amount of sleep each night. I’ve said it over and over, and I’m sure I’ll be saying it until the day I hang up my stethoscope—and likely long after. It’s that important.

But today, I want to focus in on one particular piece of the sleep hygiene puzzle that often goes overlooked. Or, at least, the advice often goes ignored.

I’m talking about the blue light emitted by all of our favorite electronics.

Why You Should Avoid Blue Light At Bedtime

As the world becomes more electronic, our screens have become virtually unavoidable.

Lots of people like to fall asleep with the TV on. The background sound sooths them.

Others can’t stand the TV at night—but will check up on their email before turning in. Computer or phone in hand, they get their inbox ordered for the morning.

Still others want to tune out as they drift off—and play a game on their phone. Or read a book on their iPad.

The problem is, each and every one of those activities screws with our sleep cycle.

Specifically, the blue light, emitted by our electronic screens disrupts our circadian rhythm.

It’s worse than you think, actually. Natural light can disrupt sleep enough by itself—just ask residents of Alaska in July. If you’re not careful, you’ll be wide awake at 3 am, the sun all ablaze like a mid-day afternoon, and not even realize you should be tired.

But our screens are low-wavelength enriched, meaning they have even more blue light in them than natural light. And no wavelength interferes with sleep-inducing melatonin production more than blue light.

In fact, we have special ganglion cells that are responsible for one simple thing: Detect blue light, and produce melatonin when it isn’t around.

Melatonin, you’ll remember, is your primary sleep hormone. Its presence tells the body when to hit the sack, while its absence tells the body to wake up.

But it does more than just that. Every single cell in your body has its own circadian rhythm, and that’s controlled by blue light as well.

In other words, when you stare at a screen before bedtime, every system in your body thinks it’s wake-up time and goes into high alert. Your digestive system starts up, your brain starts spinning, your kidneys kick into gear—absolutely everything.

I bet you didn’t realize that blue light is at least partially responsible for your midnight trips to the bathroom.

The real problem is, when you feed your body blue light before bedtime, it interrupts a whole host of systems. You aren’t able to recover as you should, you have trouble getting to sleep in the evening, you wake up tired in the morning, and the cycle builds upon itself each day.

There aren’t conclusive studies detailing just how harmful blue light before bed is, but they’re coming. And the preliminary findings are disheartening indeed.

How to avoid blue light before bed

The best possible thing you can do for yourself is to shut off your screens when the sun goes down.

We’re wired as daylight beasts—we live in the sun. The advent of the light bulb interrupted those schedules, but our screens are doing exponentially more harm. Try to shut them down. Talk to your family, or read a book instead.

Even e-book readers like the Kindle, when they display using e-ink and not active light sources, are a better option.

However, I understand that the world we live in doesn’t always allow that. There’s no time to binge your favorite programs in the space between work and sunset—if there is even any gap!

That’s why, at the least, shut down your screens an hour before you sleep. That will help you drift off, yes—but it will also signal your body that bedtime is nigh, and all your organs can take a rest as well.

Finally, if that proves impossible, do me this small little favor, I beg you. Install apps in your phones and computers that filter out blue light for night viewing.

There are a whole host of options available, like f.lux for MacOS, or Twilight for Android. (Getting one on your iPhone is a little more difficult, as Apple doesn’t let apps fiddle with display controls.)

The important thing is this: Avoid screens during evening hours. Especially avoid them the hour before you go to bed. And if you must view something, do it through a filter.

It sounds like a little change—which might be why so many people ignore this advice. But trust me—reducing or eliminating blue light at night can have a profound effect on your health.

It’s well worth the effort.


Last Updated: August 16, 2018
Originally Published: January 22, 2016