Heya ,

Did you miss me? I missed you!

That’s why I’m back today with another Sleep Destroyer for ya.

Now, today’s topic may very well be something you already know about, especially if you’ve done any previous research on sleep.

I call it the Big Bad Wolf of Sleep Destroyers because it disguises itself to appear innocent and innocuous but can ravage your sleep pretty bad.

But I’ve got a whole game plan for you, so don’t you fret your pretty little heart.

This Big Bad Wolf occurs naturally and helps regulate our circadian rhythm, but it’s absolutely catastrophic to your sleep when you’re exposed to it at the wrong time.

I’m talking, of course, about...

Sleep Destroyer #3: Blue Light

Technically, any artificial light at night will affect your sleep, but blue light is by far the most destructive, since the strongest wavelengths for our natural biological clocks in the electromagnetic spectrum are blue [1].

There’s a 99% chance you’re getting some beamed directly into your brain right now by simply reading this on a digital device (I left that 1% for people who may have printed their emails on paper. I would include Kindle Paperwhite readers, but I’ve discovered that those devices also emit blue light).

90% of Americans report some technology use in the hour before bed.[2]

Now, if you’re reading this in the daytime, there’s no problem because we actually need light to tell us to be awake and regulate our circadian rhythm (based on our evolution to rise with the sun and sleep when it sets).

It’s actually really healthy and helpful to get more natural light in the morning. Simply letting the sun’s rays hit your skin can shake off sleep fog and elevate your energy.

The problem occurs when the sun sets, and our world gets lit up by all that darn technology.

That’s because when it gets dark outside, our suprachiasmatic nucleus (remember this bad boy from our last email?) uses melatonin to start signaling our brains that we should be tired.

Melatonin (which has the awesome nicknames “the hormone of darkness” and “the vampire hormone”) is a hormone that helps regulate the timing of when we go to sleep.

It’s like a messenger running around our brains and bodies yelling “IT’S DARK! IT’S DARK! IT’S DARK!”

This kicks off the rest of the sleep process.

To be clear, melatonin doesn’t do much to actually generate sleep, which is a huge misconception.

This is why “just take a melatonin supplement” is NOT the most effective method to improve your sleep (I’ll discuss this in a future email).

Melatonin rises roughly around dusk and is released into your bloodstream via the pineal gland, which is an area buried in the back of your brain.

Once you’re sleeping, melatonin decreases in concentration throughout the night. When sunlight enters your brain through your eyes (yes, even through closed lids), the pineal gland shuts off the release of melatonin.

In the absence of the “IT’S DARK” announcement, our brains and bodies start to wake up.

Artificial light, and especially blue light, tricks our brains into thinking it’s still daytime and puts a muzzle on melatonin, so we don’t get the signal to initiate the sleep process.

For example, one study found that using an iPad for two hours prior to bed blocked the melatonin release by 23%:

“Compared to reading a printed book, reading on an iPad suppressed melatonin release by over 50 percent at night. Indeed, iPad reading delayed the rise of melatonin by up to three hours, relative to the natural rise in these same individuals when reading a printed book. When reading on the iPad, their melatonin peak, and thus instruction to sleep, did not occur until the early-morning hours, rather than before midnight.”[3]

This affected the research subjects’ sleep quality in 3 ways[3]:

• They lost significant amounts of REM sleep following iPad reading
• They felt less rested and sleepier throughout the day
• They suffered a 90-minute lag in their evening rise of melatonin levels for several days after they stopped using the iPad

So how do you avoid the harmful effects of blue light at night without regressing to a stone-age lifestyle?

The best advice for avoiding blue light is to remove all electric and artificial light from your life and use a candle to see in the dark (fire emits a warmer light at a different wavelength and doesn’t disrupt your melatonin cycle[4].

But since that’s really not gonna happen, here are a few things you can do to avoid the negative effects of blue light on your sleep:

Stop any screen time at least an hour before bed.

I’d even suggest up to 3 hours before bed, since blue light exposure can delay your melatonin release by a few hours.

Also, even if you’re not directly looking at a screen (like if you fall asleep with the TV or computer monitor on, or light from a lamp outside sneaks through your window), the light can still get into your eyes and affect your sleep. A sleep mask or blackout shades will help with this.

Use blue-light filtering software and apps:

Since #1 is going to be nearly impossible to follow, you can reduce some of the blue light from your screens with these apps:

• macOS (Apple computers) – f.lux
• iOS (iPhones, iPads, maybe some iPod touches) – built-in feature called “Night Shift”
• Android devices – built-in feature called “Night Mode” 
• Windows – Built-in feature called “Night light” (on some Windows versions); fl.ux

Wear blue-light blocking glasses

In combination with using the f.lux app and night shift on my devices, I wear blue-light blocking glasses at night by a brand called Swanwick Sleep (btw, this is an affiliate link that could result in SleepHackers getting a small commission for any sales, so if you’re not cool with that, click here for a non-affiliate link).

As soon as the sun goes down (or 1-2 hours before bed, because sometimes they don’t align), I’ll throw on my Fitover Night Swannies (which go over my own glasses).

When I first started wearing them, I noticed a HUGE difference in the quality of my deep sleep.

Here’s my Oura Ring showing a night without them versus a night with them:

Without blue light blocking glasses

With blue light blocking glasses

This changed my life because it allows me to work on my Macbook, watch Netflix, or scroll through Instagram (my biggest evening vice) without compromising my sleep quality.

After testing out different brands of blue light blocking glasses, I chose to partner with Swanwick because I liked how comprehensive they were about sharing the science behind their products, the wide range of styles they offer, and their hassle-free 30-day refund policy.

But you don’t have to use this brand – look for any blue-light blocking glasses that have an orange tint.

Why the orange tint?

If you check out Swanwick, you’ll notice they offer daytime and nighttime blue-light blocking glasses.

You can read more about the details here but basically the day glasses (with clearer lenses) prevent digital eye strain and block certain wavelengths of blue light while allowing the rest to pass through (to signal your brain that it’s daytime), while the night glasses (with the orange lenses) block ALL blue light to prevent melatonin suppression.

Since my prescription glasses already have daytime UV/blue light blocking capabilities already, I only use the nighttime Swanwick glasses. 

The only downside to the nighttime lenses is they change the color of whatever you’re looking at, so they’re not the best for doing design work.

So whether you buy a pair from Swanwick or another company, it’s worth investing in blue light blocking glasses.

See you soon with another Sleep Destroyer!

Ready...set...sleep 😴

— Michael, Chief SleepHacker

PS — If you skipped the email to see what’s down here, go back up a little ways to read how to avoid blue light at night. Also you can buy my blue light blocking glasses of choice by clicking here.

References:

1. https://www.tandfonline.com/doi/abs/10.3109/07420520903523719
2. https://jcsm.aasm.org/doi/10.5664/jcsm.3274
3. Walker, M. P. (2018). Why we sleep: Unlocking the power of sleep and dreams.
4. https://bit.ly/3cCEkmS