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How Alcohol Affects Your Sleep

Alcohol and Its Effects on Your Sleep

Sleeping in a cozy bed

Waking up the morning after happy hour feeling exhausted and sluggish is not uncommon. Even if you get the recommended eight hours (or more), you may still wake up feeling like you barely slept at all. What causes this phenomenon and what can you do to wake up feeling rested the morning after a few drinks with friends?

There is a significant amount of research that explains why drinking alcohol leaves you feeling tired even after what you may think is a good night’s rest. Luckily, there are some steps you can take to avoid the morning-after sluggishness we all know and dread. Here is a closer look at how alcohol interferes with good sleep and how to minimize the effects happy hour can have on quality rest.

What Does Good Sleep Look Like?

Waking up in the morning

Most people assume that as long as they sleep for eight hours, they’re getting a good night’s rest. However, staying in bed for this recommended amount of time doesn't necessarily translate to quality sleep, especially if alcohol is involved. Quality sleep means you:

  • Fall asleep fairly quickly (about 30 minutes after going to bed).
  • Do not wake up more than once and do not experience frequent tossing, turning, or general restlessness.
  • Wake up relatively easily or at an appropriate time (no oversleeping or waking hours before your alarm).

If you have experienced a good night of sleep, you shouldn’t wake up feeling groggy and tired. Instead, you’ll feel refreshed, alert, and ready to take on the day.

The Science Behind Quality Sleep

Quality sleep involves two kinds of sleep: REM (rapid eye movement) and non-REM sleep. Non-REM sleep has three stages, while REM sleep only has one (citation). If you are sleeping well, you’ll go through the four stages of sleep about four to six times throughout the night, with each full cycle lasting around 90 minutes (citation). The four stages of sleep include:

The four stages of sleep

Several parts of the brain are at work both when you fall asleep and as you sleep (citation). For example, the hypothalamus and its contained cells influence sleep and wakefulness through light detection from the eyes. Likewise, the thalamus grows quiet so you can tune out sensory stimulation during the first stages of sleep, and the pineal gland produces melatonin, a hormone that helps you sleep. Other parts of the brain are involved as well, such as the forebrain, midbrain, and amygdala. Different regions become less and more active as you cycle through each of the four sleep stages.

What Does Drunk Sleep Look Like?

Sleeping while intoxicated (or even after just a few drinks) can be vastly different from sleeping sober. You’ll often feel the difference in the quality of sleep the next morning. Even though being intoxicated can mean you fall asleep faster, you may wake more frequently throughout the night, experience restlessness, and have a hard time waking up the next morning. It’s common to feel extremely drowsy the next day following a night of drinking, even if you stayed in bed for longer than usual the morning after.

Why does alcohol change how we sleep? Let’s take a closer look at what happens inside the body and brain during an alcohol-influenced sleep cycle.

Does Alcohol Help You Fall Asleep?

Yes. Alcohol is classified as a depressant, which means it can lead to a relaxed state or feeling sleepy. In short, it acts as a sedative, which results in decreased sleep latency times for most people (citation). Alcohol also boosts adenosine levels, a chemical produced by the brain that helps you fall asleep and wake up (citation).

How and Why Does Alcohol Disrupt Sleep?

While alcohol may help you fall asleep faster, the positive effects stop there. Shortly afterward, your body experiences a "rebound effect" that disrupts your sleep for much of the rest of the night (citation).

Why does this happen?

To understand alcohol’s effects on sleep, you first have to understand how your body processes alcohol. After you drink alcohol, it enters the bloodstream via the digestive system and gets broken down by the liver. This is a slow process. The sedative effects of alcohol kick in for a bit, but then the body rebounds as it is being processed.

This rebound effect occurs for several different reasons.

For one, alcohol interferes with melatonin production around two to three hours after consumption, and melatonin helps you stay asleep (citation). This explains why it is not uncommon for intoxicated people to wake up at night and have difficulty falling back asleep. Alcohol also disrupts or changes REM sleep (citation). Several studies have demonstrated that alcohol consumption before bed suppressed REM earlier in the sleep cycle and led to less REM during the night (citation). Finally, alcohol alters slow-wave (delta) sleep patterns while promoting wakefulness as it is metabolized (citation). This combination of effects disrupts sleep and can lead to poor quality sleep overall.

The extent to which alcohol affects sleep patterns obviously can differ depending on how many drinks were consumed. One study assessed the association between alcohol intake and the body’s stress recovery capabilities – which are highly related to sleep quality (citation). Researchers found considerable differences in the body’s ability to recover from stress depending on how many drinks were consumed:

  • Light (less than two drinks for men and less than one drink for women). Decreased stress recovery ability by 9.3%.
  • Moderate (two drinks for men and one drink for women). Decreased stress recovery by 24%.
  • High (more than two drinks for men and more than one for women). A 39.2% decrease in the body’s ability to recover from stress.

Tips For A Better Night's Sleep After Drinking Alcohol

Asleep in a bed, feet out of the covers

If you’re planning to have a few drinks with friends tonight, here are a couple of tips that may help you avoid sleep disruptions. To make the most of the day after drinking, remember to:

  • Allow at least two hours between your last drink and bedtime, if you can. In general, try to go to bed sober.
  • Drink responsibly, pace yourself, and stop drinking earlier in the night. Replace that “last-call” round with water or a non-alcoholic beverage.
  • Make sure to eat a healthy meal before and/or during drinking and try to squeeze in your normal exercise routine before hitting up that happy hour.
  • Avoid caffeine and nicotine while drinking, especially late at night, as these are stimulants and will absolutely disrupt your sleep.
  • Practice good habits before bed like skincare, reading, and taking a break from electronics.
How Many Hours Before Bed Should You Stop Drinking?

A clock indicating the time

The average person processes one alcohol-based drink every one to two hours. However, several factors influence this process, such as gender, age, and body mass. With this in mind, if you have two drinks in a short window of time, let’s say two 12-ounce beers or two cocktails within 15 minutes, you may need to wait around four hours before going to bed. This can be extremely unrealistic, especially if you started drinking late. However, if you space these drinks out over two or three hours, your body will likely have already processed the alcohol before going to sleep.

A good general rule is to allow two hours for every drink you consume. Remember, start counting the time from when you start drinking, not from when you finish drinking. The longer you give your body to break down the alcohol before going to sleep, the less likely it will affect sleep quality.

What Else Can You Do?

While a good night’s rest is ultimately dependent on you, follow our tips for better sleep after happy hour and set yourself up for success tomorrow with ZBiotics. Make ZBiotics your first drink of the night, pair it with responsible drinking habits and a good night’s sleep, and wake up feeling fresher tomorrow!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice.