Hey ,

You're back! Or... I guess I'm back in your inbox.

Either way, it means we get to keep talking about sleep!

A few days ago, I told you how to avoid one of the most common Sleep Destroyers so you can improve your sleep quality…

Don’t eat within 3 hours of going to bed.

I personally found this to have a huge impact on my sleep quality, so if you implemented it, I wanna know if you noticed any impact on your sleep (just reply to this email and let me know). 

Today’s Sleep Destroyer is closely related to that.

Depending on your lifestyle, this may be the most challenging Sleep Destroyer to avoid, or the easiest. But even if it’s the latter, keep reading because there’s some sleep science in this email that’s worth learning about for other reasons.

But before I share it, here's a reminder of why it’s worth putting in the work to improve your sleep.

In his book, Why We Sleep: Unlocking the Power of Sleep and Dreams, sleep expert Dr. Matthew Walker (director of UC Berkeley’s Sleep and Neuroimaging Lab) writes:

“Sleep is the single most effective thing we can do to rest our brain and body health each day — Mother Nature’s best effort yet at contra-death.”

“Within the brain, sleep enriches a diversity of functions, including our ability to learn, memorize, and make logical decisions and choices...sleep recalibrated our emotional brain circuits, allowing us to navigate next-day social and psychological challenges with cool-headed composure.”

“Downstairs in the body, sleep restocks the armory of our immune system, helping fight malignancy, preventing infection, and warding off all manner of sickness”.

This email is gonna be a long one, so let's draw on some of that cool-headed composure and dive right in.

Sleep Destroyer #2: Drinking alcohol

This sounds counterintuitive, right?

I definitely went through a period of my life where I couldn't sleep without a glass (or 5) of wine or whisky before bed.

In fact, about 20% of adult Americans drink alcohol before bed as a sleep aid.

Now, before you kill me, let me be clear: you can still drink alcohol, if that’s something you enjoy doing. 

BUT… 

…if you want to live a sleep-friendly life, you’ll want to manage your drinking. 

I’ll share a doctor’s recommendation on how to do that at the end of this email.

Okay, onto the science.

Research from University of Missouri (MU) School of Medicine in Columbia, MO, showed that, while alcohol can bring on sleepiness and help you fall asleep, it can actually disrupt your sleep, lower your sleep quality, and even cause insomnia over time.

See, the way alcohol works to put you to “sleep” (I’ll explain why I put “sleep” in quotes in just a bit) is also what causes it to disrupt your circadian rhythms.

Here’s a quick and dirty refresher on circadian rhythms:

There’s a tiny 24-hour biological clock sitting in the middle of your brain (in the hypothalamus, to be specific) called the suprachiasmatic nucleus.

This clock communicates a daily circadian rhythm signal to every other region of your brain and every organ in your body.

Your circadian rhythm is best known for its starring role in your sleep and wake cycles, but it also controls other rhythmic patterns, such as:

• timed preferences for eating and drinking
• moods and emotions
• your core body temperature
• metabolic rate
• sex drive
• the release of hormones
• the amount of urine you produce (random, but true)

It’s the first of two factors determining your wake and sleep patterns.

The second is something called “sleep pressure.” As you read this, there’s a chemical called adenosine building up in your brain. The longer you stay awake, the more it builds up.

Have you ever reached the end of the day and been so sleepy that you felt like your eyelids weigh a billion tons?

That’s a result of sleep pressure caused by the continuous rise of adenosine. 

(This chemical will come back into our conversation when we get to caffeine in another email).

So, what does this have to do with alcohol?

Alcohol elevates levels of adenosine while blocking other chemicals that stimulate wakefulness, which may seem like a good thing to put you to sleep.

But this actually knocks your biological clock off course and blunts your natural sleep patterns, so you “sleep” and wake up at unideal times.

Now, why do I put “sleep” in quotes when referring to it in the context of alcohol consumption?

I’ll refer back to Dr. Walker to explain this:

“Alcohol sedates you out of wakefulness, but it does not induce natural sleep. The electrical brainwave state you enter via alcohol is not that of natural sleep; rather it is akin to a light form of anesthesia."

“Alcohol dismantles an individual’s sleep in an additional two ways. First, alcohol fragments sleep, littering the night with brief awakenings. Alcohol-infused sleep is therefore not continuous and, as a result, not restorative."

“Second, alcohol is one of the most powerful suppressors of REM sleep that we know of. When the body metabolizes alcohol it produces by-product chemicals called aldehydes and ketones. The aldehydes in particular will block the brain’s ability to generate REM sleep. It’s rather like the cerebral version of cardiac arrest, preventing the pulsating beat of brainwaves that otherwise power dream sleep.”

Other sleep disruptions associated with alcohol consumption include:

• More frequent need to get up and go to the bathroom, especially during the second half of the night
• Increased risk for sleepwalking and sleep eating (yes, that’s a thing)
• Greater risk for snoring and sleep-disordered breathing (alcohol can lead to excessive relaxation of the muscles in the head, neck and throat, which may interfere with normal breathing during sleep)

The bottom line here is simple: the more you drink, and the closer your drinking is to bedtime, the more it will negatively impact your sleep.

While some people have no problem abstaining from alcohol entirely, it’s just not practical or desirable for many.

So, how can you still enjoy alcohol without harming your sleep too much?

Here’s what Dr. Michael Breus, a Diplomate of the American Board of Sleep Medicine and a Fellow of The American Academy of Sleep Medicine, has to say:

“I recommend to my patients drinking 2-3 times a week. That recommendation is the same for both men and women. This provides enough room to enjoy an after-work cocktail with friends, indulge in a glass of wine at your favorite restaurant, and crack open a beer after a weekend’s worth of chores around the house—all without interfering with healthy sleep and circadian rhythms.”

And based on the science, you’ll be better off if you drink earlier in the day, or follow a similar guideline to eating and avoid drinking alcohol within 3 hours of bedtime.

There you have it, folks.

Ready...set...sleep 😴 

— Michael, Chief SleepHacker

PS — In our next email, I’ll go over what's arguably the single most destructive Sleep Destroyer affecting billions of people around the world. I’ll also share a method that I’ve personally tested to fight this, and share some data from my Oura Ring that shows how much of a difference it’s made on my sleep.