How does alcohol affect your sleep?

Does alcohol help with sleep – or should it be avoided? Here’s what you should know about how it impacts your sleep cycle.

Consuming alcohol may make you sleepy because of its sedative properties. Nevertheless, people who drink before bedtime frequently experience disruptions later in their sleep cycle [1].

What happens after you consume alcohol?

After a person drinks alcohol, the substance gets absorbed into the bloodstream from the stomach and small intestine [2]. Enzymes in the liver ultimately metabolize it, but because this is a relatively slow process, extra alcohol will continue circulating throughout the body.

The effects of alcohol broadly depend on the consumer. Essential factors include the amount of alcohol and how quickly you consumed it, as well as the individual’s age, body type, sex and physical condition.

Studies on the relationship between alcohol and sleep have been around since the 1930s [3]. Though, some aspects of this relationship are still unknown. Research revealed that those who drink large quantities of alcohol before going to bed are often prone to delayed sleep onset – meaning they need more time to fall asleep. 

Alcohol and its influence on the stages of sleep

To further understand how alcohol impacts sleep, here are the different stages of sleep cycle. Sleep consists of four stages: three non-rapid eye movement (NREM) stages and one rapid eye movement (REM) stage.

  • Stage 1 NREM (light sleep phase): the transition period between wakefulness and sleep, wherein the body will begin to shut down. The individual’s breathing, eye movements and heartbeat start to slow down as muscles will relax. Brain activity begins to decrease, as well.
  • Stage 2 NREM: heartbeat and breathing rates continue to slow down as they go toward deeper sleep. Body temperature will decrease, and the eyes will become still. The second stage is usually the longest of the sleep cycle stages.
  • Stages 3 NREM (slow-wave sleep phase): breathing rates, brain activity and heartbeat reach their lowest levels. Eye movements stop, and the muscles are completely relaxed.
  • REM: REM sleep kicks in around 90 minutes after you initially fall asleep. Eye movements will restart, and breathing rate and heartbeat will go faster. Dreaming usually happens in REM sleep. This is also thought to play a role in memory consolidation [4].

These stages repeat cyclically throughout the night. Each cycle should last roughly 90 to 120 minutes, resulting in four to five cycles for every eight hours of sleep. 

Consuming alcohol before bed can add to the suppression of REM sleep in the first two cycles. Because alcohol is a sedative, sleep onset is often shorter for drinkers – and some fall into a deep sleep rather quickly. 

As the night advances, this can create an imbalance in the middle of slow-wave sleep and REM sleep. This can result in less of the latter and more of the former – decreasing overall sleep quality, meaning there will be shorter sleep duration and more sleep disruptions.

Ways that alcohol can affect sleep

  • Alcohol and Insomnia: Insomnia is the most typical sleep disorder. It’s defined as ‘a persistent difficulty with sleep initiation, duration, consolidation, or quality.’ Insomnia happens despite the possibility and urges to sleep and leads to excessive daytime sleepiness and other harmful effects.

Alcohol can lessen REM sleep and induce sleep disruptions. Individuals who drink before bed may experience insomnia symptoms and feel excessively sleepy the following day.

This can lead to a cycle of self-medicating with alcohol to feel sleepy, drinking caffeine and other stimulants in the day to keep awake, and then using alcohol as a sedative to counteract the effects of these stimulants [5].

Binge-drinking or consuming an excessive amount of alcohol in a short period that results in blood alcohol level of 0.08% and above can be especially damaging to sleep quality. Current studies show that people who took part in binge drinking every week were notably more likely to have issues falling and trying to stay asleep. 

These findings were factual for sexes. Similar data were observed in adolescents and young adults and middle-aged and older adults [67].

Researchers have noted a connection between long-term alcohol abuse and chronic sleep problems. People can develop a tolerance for alcohol relatively fast, leading them to drink more before bed to provoke sleep. Those diagnosed with alcohol use disorders usually report symptoms of insomnia.

  • Alcohol leading to sleep apnea: sleep apnea is a condition indicated by abnormal breathing and momentary loss of breath during sleep. These lapses in breathing can, in turn, generate sleep disruptions and lower sleep quality. 

Obstructive sleep apnea (OSA) happens due to a physical blockage behind the throat, while central sleep apnea (CSA) occurs because the brain cannot correctly signal the muscles that control breathing.

During apnea-related breathing episodes – which can happen throughout the night, the individual may make choking noises. People with sleep apnea are also inclined to loud, disruptive snoring.

Some studies suggested that alcohol contributes to sleep apnea because it causes the throat muscles to relax, which creates more resistance during breathing. This can worsen OSA symptoms and lead to disruptive breathing episodes and heavier snoring. 

Additionally, drinking a single serving of alcohol before bedtime can lead to heavy snoring and OSA. This even happens to people who have not been diagnosed with sleep apnea. 

The relationship between sleep apnea and alcohol has been researched somewhat extensively. The agreement based on various studies is that consuming alcohol increases the risk of sleep apnea by 25% [8].

  • Alcohol and the urge to urinate: since alcohol is a diuretic or a substance that increases urine output, you may wake up to go to the bathroom. Moderate amounts of alcohol, primarily wine and spirits, have an early diuretic effect, especially in the elderly [9].

It’s unclear whether the urge to urinate wakes you up or if you’re just more in tune with your body in the second half of the night because you’re sleeping more intermittently.

Some people drink alcohol and use it as a sleep aid [10]. If you are consuming alcohol, try to avoid having it too close to your bedtime. 

Give your body some time to process the alcohol you’ve consumed before you try to sleep. On average, it takes an hour to process a unit, but this can differ widely from person to another.

[1] https://www.sleepfoundation.org/nutrition/alcohol-and-sleep
[2] https://www.cdc.gov/alcohol/faqs.htm
[3] https://pubs.niaaa.nih.gov/publications/arh25-2/101-109.htm
[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768102/
[5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5821259/
[6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3748176/
[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4221579/
[8] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5840512/
[9] https://www.nytimes.com/2022/01/25/well/mind/alcohol-drinking-sleep.html[10] https://www.piedmont.org/living-better/how-does-alcohol-affect-your-sleep

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The information included in this article is for informational purposes only. The purpose of this webpage is to promote broad consumer understanding and knowledge of various health topics. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.