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Alcohol and Sleep: Effects and Research


Author: Thomas Roth

Last Updated: 6/04/2022

Alcohol’s effect on sleep has been studied extensively in recent years. Because alcohol is a central nervous system (CNS) depressant, it slows down brain function. When alcohol slows down brain function it causes drowsiness, fatigue, loss of coordination, and other side effects. While these side effects can help someone fall asleep faster, abusing alcohol leads to problems with sleep and sleep quality. In fact, alcoholics commonly experience insomnia. 

On the other hand, only having a few standard drinks every few days doesn’t have a big impact on sleep. Therefore, alcohol only becomes an issue when it’s abused or used as a sleep aid. People who are dependent on alcohol for sleeping can experience poor sleep quality without using alcohol to fall asleep at night.

How Does Alcohol Affect Sleep?

Alcohol has several effects on sleep. When alcohol is consumed, it’s processed by the stomach, intestines, and liver. Enzymes are secreted to break down alcohol but the process is slow. When someone falls asleep after consuming a large quantity of alcohol, organs in the body continue to break down alcohol, which can lead to sleep disruptions and delayed sleep onset. Furthermore, alcohol interacts with each stage of sleep differently.

Alcohol also interacts with sleep when someone quits drinking. When someone quits drinking, alcohol withdrawal occurs. During alcohol withdrawal, people can struggle with insomnia, sleep apnea, and even night sweats. These are all conditions that impact sleep and sleep quality.

1. Less REM sleep

When alcohol is consumed before sleeping it can lead to poor sleep quality. One reason that sleep quality is worse is because of the imbalance between sleep cycles. While alcohol causes people to fall into a deep sleep faster, this creates an imbalance between sleep cycles. On average, sleep cycles last for 90 to 120 minutes. REM sleep is the sleep stage that contributes to memory and healing, so it’s one of the most important sleep stages. Consuming alcohol before bed can cause REM sleep to become shorter, which decreases the quality of sleep. It becomes shorter because entering REM sleep too fast causes the body to adjust by extending the periods of other stages of the sleep cycle, which leads to sleep disruptions and changes in sleeping patterns.

2. Disrupted Circadian Rhythm

The circadian rhythm regulates a lot of the body’s natural rhythms. This includes the immune system, sleep cycles, basic metabolic functions, mood, and cognitive functions. When someone consumes alcohol it disrupts the body’s circadian rhythm and causes changes to the way the body regulates these functions. While a few standard drinks per week doesn’t cause drastic changes, abusing alcohol can damage the circadian rhythm and lead to sleep impairment. A disrupted circadian rhythm can lead to sleep loss, insomnia, sleep disturbances, and other symptoms.

3. Getting up for Peeing

Alcohol causes people to urinate frequently. It causes people to pee because it’s a diuretic. A diuretic is a substance that causes water loss through the urine. Alcohol causes this by limiting the production of hormones like vasopressin, which plays a big role in the regulation of water in the body. When alcohol promotes this loss of water, it forces the body to pee. If someone is sleeping after drinking large quantities of alcohol, this response can disrupt sleep and force someone to pee throughout the night.

4. Vivid Dreams

Alcohol can cause vivid dreams to occur when it interacts with the REM stage of sleep. REM sleep is when dreams occur and having alcohol in the body during this stage can lead to nightmares and intense dreams. In some cases, these dreams can be very intense and cause people to wake up. Vivid dreams can also lead to other symptoms like night sweats, which can make returning to sleep more challenging. Alcohol can also cause REM sleep stages to occur more rapidly, which increases the risk of vivid dreams occurring. Unfortunately, more vivid dreams increase the risk of nightmares.

What are the Stages of Sleep that are Affected by Alcohol?

Alcohol affects all the stages of sleep. It causes people to enter REM sleep faster, which can make REM sleep shorter and more frequent. When REM sleep is more frequent, it increases the risk of vivid dreams and nightmares. More REM sleep in shorter intervals also leads to a loss in sleep quality. REM sleep is supposed to last for between 90 and 120 minutes, like other sleep cycles, but alcohol causes people to bounce around sleep cycles faster. For this reason, people can wake up feeling groggy and tired.

That said, alcohol also impacts other stages of sleep. One study reviewed a total of 27 other studies and concluded that alcohol does not improve sleep and significantly alters each sleep cycle and the rate at which people enter them. It impacts the wake cycle, N1 stage, N2 stage, N3 stage, and REM sleep. An overview of each sleep stage is listed below.

  • Wake: The wake stage is what people experience when they’re awake. As alpha waves increase, beta waves decrease and people become drowsy. Once alpha waves reach the 50% threshold, it’s considered the wake stage of sleep, which is a transition from wakefulness to sleep.
  • N1: N1 is the shortest part of the sleep cycle. It represents 5% of the sleep cycle and occurs when 50% of alpha waves are replaced with low-amplitude mixed frequency activity (LAMF). During this stage, breathing is similar to wakefulness.
  • N2: N2 is another part of the sleep cycle that occurs during the first 5-25 minutes of sleep. It’s another short phase but it’s responsible for preparing the body for sleep cycles and deep sleep. During this phase, alpha waves are replaced by delta waves, and sleep spindles are created. These sleep spindles activate several systems in the body like the thalamus, anterior cingulate, insular cortices, and temporal gyri. 
  • N3: N3 is the deepest sleep stage. The body transitions between REM sleep and N3 sleep throughout the sleeping in intervals of 90 to 120 minutes. During this stage of sleep, delta waves are present and it’s challenging to wake up from this stage. Moreover, people who wake up from N3 sleep are groggy for between 30 minutes to an hour. N3 sleep is also responsible for repairing muscle and other damaged tissues in the body. 
  • REM: REM sleep is the stage of sleep that people experience dreams in. While the brain emits similar patterns as someone awake, the muscles are atonic and can’t move (some disorders can cause muscles to move, which contributes to sleepwalking). REM sleep begins in short intervals of 10 minutes but can last for up to an hour.

Depending on how much alcohol is consumed, each of these sleep stages can be impacted.

How Much Alcohol Affects Sleep?

Studies suggest that any amount of alcohol can affect sleep. Research indicates that low amounts of alcohol can reduce sleep quality by almost 10%. Furthermore, moderate drinking (more than two standard drinks) can reduce sleep quality by up to 24%. Heavy amounts of drinking impair sleep the most and can lead to a reduction in sleep quality of up to 40%. Therefore, even small amounts of alcohol can impact sleep. It’s also important to note that alcohol abuse can cause insomnia and other sleep-related problems.

How Can I Stop Feeling Tired after Drinking Alcohol?

Alcohol is a depressant, so it slows down the central nervous system. For this reason, drinking alcohol causes people to feel tired. To prevent feeling tired when drinking alcohol, there are a few tips you can use. These tips to help you stop feeling tired after drinking alcohol are listed below.

  • Plan out your drinking the day before 
  • Make sure you’ve eaten enough food throughout the day 
  • Drink lots of water when drinking alcohol 
  • Stay out of the sun 
  • Pick alcoholic beverages low in alcohol percentage 
  • Don’t consume alcohol 
  • Only consume small amounts of alcohol

These tips can help you feel less tired when drinking alcohol.

What are the Facts about Alcohol and Sleep?

Alcohol and sleep have been studied extensively since the 1930s. However, studies have mixed findings on what alcohol’s specific effect on sleep is. That said, it’s clear that alcohol does cause changes to sleep and the sleep cycle. The changes that occur depend on several factors like how much alcohol is consumed, how long someone’s been consuming alcohol and even the type of alcohol. Still, it’s evident that alcohol impairs sleep quality and can make people feel more tired the next day.

Does Alcohol Affect Men and Women Differently in terms of Sleeping?

Yes, alcohol has a different effect on men and women in terms of sleeping. Studies indicate that women have a higher risk of developing insomnia when consuming alcohol. While insomnia is a big factor for women, alcohol does not increase the risk of insomnia occurring in males. That said, alcohol-related sleep problems are similar aside from insomnia. Overall, alcohol reduces sleep quality in men and women.

Can You Use Alcohol for Dealing with Sleeping Disorder?

Alcohol shouldn’t be used for sleeping disorders. While alcohol can help people fall asleep faster, it disrupts natural sleep patterns and leads to worse sleep in men and women. People who use alcohol as a sleep aid can also become dependent on alcohol, which increases the risk of alcohol abuse disorder (AUD) occurring. When dealing with sleep disorders, it’s important to consult with a doctor instead of self-medicating with substances like alcohol.

Does Alcohol Cause Sleep Apnea?

Yes, alcohol can cause sleep apnea. Alcohol can also increase the risk of sleep apnea events lasting longer for individuals that have OSA. Research is inconclusive on whether or not alcohol can result in someone developing a sleep apnea condition. Moreover, it’s unclear if someone who develops sleep apnea from alcohol consumption can cure the condition by quitting drinking. For these reasons, the correlation between alcohol and sleep apnea is not clear.

Does Alcohol Help You Sleep or Keep You up?

Alcohol helps people fall asleep and enter sleep rapidly. Because alcohol slows down the nervous system, it makes people feel drowsy. While alcohol makes people fall asleep faster, it doesn’t improve the quality of sleep. In fact, alcohol reduces the quality of sleep in otherwise healthy individuals. Alcohol should not be used to help you fall asleep.

Can You Take Alcohol with Sleeping Pills?

No, you can’t take alcohol and sleeping pills. Taking alcohol and sleeping pills is dangerous because sleeping pills and alcohol are CNS depressants. Combining sleep medication with alcohol can lead to drowsiness, loss of consciousness, changes in heart rate, and induce a coma. Always consult with your doctor before mixing alcohol with other substances, especially sleep medications.

What are the Other Effects of Alcohol?

Alcohol has several effects on the body. Consuming alcohol can lead to digestive problems, cardiovascular disease, and other problems.

Below are the other effects of alcohol.

  • Liver disease 
  • Cognitive impairment
  • Loss of coordination 
  • Trouble walking
  • Insomnia 
  • Digestive problems
  • Stomach discomfort 
  • Nausea and vomiting
  • Blacking out (memory impairment)

These are only some of the effects of alcohol. Alcohol can have other effects depending on the person who consumes it.