Last Updated on December 12, 2019 by Morris Green

If you’ve ever had too much to drink, you know that drowsiness is one of the main side effects of alcohol. 

Alcohol is fundamentally a depressant. While it loosens social inhibitions, it also slows down your brain. To that end, some people even use alcohol as a sleep aid – and it’s true, alcohol can reduce the time to fall asleep.

(Don’t use it for that.)

In this post, I’ll explore why alcohol hurts your sleep. We’ll walk through the interactions between alcohol and sleep and talk about why you should find a better way to catch your Zs.

What is Alcohol?

Alcohol, also known as ethanol or ethyl alcohol, is the main ingredient found in beverages such as wine, beer, and other spirits, which causes drunkenness.

Consumption of alcohol plays a significant role in social culture – we even see evidence of its usage in early Chinese and Egyptian civilization. Alcohol lowers social inhibition, throws off your balance, affects your judgement, and excess drinking causes vomiting, passing out, or even death.

The Dangers of Alcohol

Alcohol is extremely addictive, and one of the leading causes of preventable death. More than 80,000 people a year in the United States die from the effects of alcohol, from everything from acute alcohol poisoning to drunk driving deaths.

On a more day to day level, alcohol can also mess with your sleep. Sleep is a restorative process, and a mandatory mechanism in a human, and anything that disrupts it is terrible long term.

If you haven’t reconsidered your drinking habits for other reasons, consider alcohol’s effects on your sleep. Let’s talk about some of those effects now.

The Body, Alcohol, and Sleep

Alcohol is well-known as a sedative and hypnotic drug. Alcohol mimics the neurotransmitter GABA in your brain – GABA upregulation is the mechanism behind how benzodiazepines have sedative properties.

(As an aside, it’s why combining alcohol with sedatives is so dangerous. Combining them can depress your heart rate and breathing to fatal levels.)

As I mentioned, alcohol is beneficial to sleep – at low levels. Alcohol decreases your sleep latency, a fancy name for how long it takes you to fall asleep. Unfortunately, alcohol is extremely addictive, and you quickly build up a tolerance – if you relied on alcohol to sleep, you would need more and more alcohol daily – and quickly reach dangerous levels of drinking. 

Alcohol and Sleep Stages

There are four major recognized stages of sleep:

1. Stage N1: Light sleep
2. Stage N2: Light-medium sleep, where your muscles relax, and you start showing slow-wave activity in your brain
3. Stage N3: Deep sleep with lots of slow-wave activity. It’s tough to arouse a person from this stage of sleep
4. REM: REM, or Rapid Eye Movement sleep, is where the majority of dreams occur. REM sleep is unpredictable, and people move their eyelids and have irregular breathing patterns

Alcohol’s Effect on Sleep Stages

Alcohol and sleep as a topic has been blessed with extensive research. It turns out, especially during the second half of the night, alcohol causes your body to spend more time in lighter stages – N1 and N2 – than would be typical. 

In most studies, the doses of alcohol are metabolized in the second half of the night, so this reaction is a rebound effect from alcohol’s effects on the first half. Those same studies show that alcohol suppresses REM sleep, and REM sleep is also more common in the second half when alcohol is metabolized.

We don’t know what the ideal sleep stage breakdown may be – but alcohol demonstrably changes your sleeping patterns. And to my early discussion about becoming dependent on alcohol quickly: studies demonstrated tolerance begins after only a mere three nights.

Alcohol, Sleep, and Breathing

When the body is in sleep mode, the muscles relax, including your throat and airways. For most people, this is okay – at rest, you require less oxygen, and your body can expend more resources on other reparative processes. For some people, sleep can be dangerous because of a condition known as sleep apnea.

Sleep Apnea

Sleep apnea is a potentially dangerous disorder where you don’t take in enough oxygen from your sleep. People with sleep apnea might snore loudly, gasp, or even experience gaps in their breathing.

Alcohol, as a depressant, relaxes the muscles in your mouth and throat even more than they would relax on their own. One systematic review of alcohol and sleep apnea concluded alcohol increases the risks of apnea by a whopping 25%.

Sleep apnea has other known risk factors: advancing age, heart issues, use of sedatives, obesity, smoking, nasal congestion, and (as usual) a family history. 

Especially if you’ve got a few of those risk factors, you should avoid alcohol to reduce the chances of experiencing dangerous apnea.

Other Alcohol and Sleep Interactions

Sleep apnea isn’t the only danger that goes hand in hand with alcohol. (It’s not even the sole respiratory risk). Here are some other things to keep in mind about alcohol and sleep.

Alcohol and Your Gag Reflex

Alcohol’s depressant effects also suppress your gag reflex. Additionally, alcohol is, well, a poison as well as a stomach irritant – alcohol in excess can cause indigestion but also vomiting. Sleep, a suppressed gag reflex, and alcohol can be a fatal combination – a person “sleeping off” the effects of alcohol is at risk of aspirating vomit.

Losing Consciousness with Alcohol

Alcohol doesn’t just cause you to fall asleep quickly. It can even cause you to become unconscious involuntarily. 

Passing out from alcohol can be extremely dangerous. If you lose control while in an upright condition, you could injure yourself while falling. Even worse, if you lose consciousness while operating a vehicle or bicycle, you could be hurt or even killed. Especially in the case of drunk driving, you can also be an extreme risk or even fatal to others.

You should never drink to the point where you lose consciousness. If you are having issues controlling your consumption, you should get professional help.

Other Effects of Drinks

I’ve concentrated on alcohol in this post, but know that how you consume that alcohol can also have risks. Most commonly, people in the United States get their alcohol in beer and wine.

Alcohol is a mild diuretic, but especially with beer, you might take in a large amount of liquid during an evening. If you have to wake to urinate one or a few times, it immediately interrupts your sleep. Additionally, large amounts of fluid are bloating and uncomfortable – in general, consuming a large number of beers will lower your comfort and interrupt your chance at quality sleep.

Wine tends to have a higher concentration of alcohol than beer, but it has its unique risks. While sulfites in wine are a bogeyman, only around 1% of people are sensitive or allergic to sulfites. 

The more significant risk from wine comes in the form of histamines. Histamines in excess can trigger anything from hypertension to flushing to stomach issues – and commonly, nasal congestion and breathing issues. Combining nasal congestion with alcohol’s effects on your breathing can amplify your risks for other, more dangerous conditions such as sleep apnea.

For a Good Night’s Sleep, Stick to Water

The risks most definitely outweigh the reward when it comes to alcohol use and sleep. Even if alcohol works in the short term to help you fall asleep quickly, you quickly grow dependent – in the study I turned up, that might mean in as little as three days.

Addiction and dependency are no laughing matter. Your best sleep will come naturally – before turning to substances, try to increase your sleep hygiene: drink caffeine at appropriate times, avoid artificial blue light (especially in the evening), and try to wind down with a book or relaxing activity.

And if you find yourself addicted to alcohol – for sleep or otherwise – treat it seriously. Find a trustworthy expert to help you reduce your dependence.