If you drink alcohol, chances are you’ve had a night where a few drinks left you feeling drowsy. Alcohol is a depressant, which means it can help you fall asleep faster (and in fact, the National Sleep Foundation estimates that 20% of Americans use alcohol to help them fall asleep — which is not recommended). However, it can affect the quality of your sleep, and not in a good way.
In 2013, researchers reviewed 20 studies centered on alcohol and sleep for an overarching look at the detrimental impacts of alcohol on nighttime rest. “This review confirms that the immediate and short-term impact of alcohol is to reduce the time it takes to fall asleep,” Irshaad Ebrahim, director of the London Sleep Center and lead author of the review, said in a statement. “In addition, the higher the dose, the greater the impact on increasing deep sleep.”
The review also found that alcohol reduces your amount of REM sleep. “In sum,” said Chris Idzikowski, director of the Edinburgh Sleep Centre, “alcohol, on the whole, is not useful for improving a whole night’s sleep. Sleep may be deeper to start with, but then becomes disrupted. Additionally, that deeper sleep will probably promote snoring and poorer breathing. So, one shouldn’t expect better sleep with alcohol.”
This piece will cover all the different ways alcohol affects sleep, including making you fall asleep quicker, decreasing the amount of time spent in REM sleep, contributing to vivid dreams and nightmares, increasing the number of times you wake up during the night, and upping your risk of obstructive sleep apnea.
It will also touch on how hangovers can affect your sleep and the links between alcohol use disorder and sleep. Finally, it will offer resources for anyone who wants to learn more about how alcohol affects sleep, as well as resources for anyone concerned about their drinking or seeking assistance for alcohol use disorder.
Alcohol Can Cause Nighttime Wakeups
Because alcohol is a diuretic, you may wake up more often to go to the bathroom during the night if you have been drinking. Alcohol actually decreases how much antidiuretic hormone your body produces, causing lowered reabsorption of water. So, your kidneys kick into gear and your body loses more fluid through urination. After a night of drinking, you may wake up needing to go, even if your bladder doesn’t typically bother you at night.
Another issue? Alcohol may affect your circadian rhythms, leading to nighttime wakeups. A small 2010 study published in the journal Alcoholism: Clinical & Experimental Research found that chronic drinking disrupted circadian rhythms. Researchers compared blood samples from 22 men who met the diagnostic criteria for alcohol dependence with samples from 12 subjects who did not. They found that the groups had genetic differences related to their circadian clocks.
“In other words, chronic alcohol consumption was associated with a destruction of normal circadian clock gene expression,” study author Sy-Jye Leu, a researcher at Taipei Medical University, said in a statement. “This altered expression is closely related to circadian rhythm dysfunction and might link to a variety of physiological problems such as sleep/wake cycle dysregulation, depression, and even cancer.”
Alcohol Is Linked To Breathing Problems During Sleep
Alcohol decreases your muscle tone, including the tissue in your airways. This can make things like sleep apnea and snoring significantly worse. Sleep apnea is a condition that causes your breathing to stop and start during sleep, and there are three different types. The most common form of sleep apnea is obstructive sleep apnea, which occurs “when your throat muscles intermittently relax and block your airway during sleep,” the Mayo Clinic says. There is also central sleep apnea when your brain does not send the right signals to the muscles that control your breathing during sleep, and complex sleep apnea, a combination of obstructive and central sleep apnea.
The symptoms of obstructive sleep apnea (OSA) include:
- Loud snoring during sleep
- Abruptly waking up while gasping or choking
- Episodes where your breathing stops during sleep
- Waking up with a sore throat or dry mouth
- Daytime fatigue
- Trouble concentrating
- High blood pressure
- Night sweats
- Decreased libido
- Headaches in the morning
- Mood changes, like feeling anxious or depressed
There are a number of factors that can increase your risk of obstructive sleep apnea, including excess weight, a narrowed airway, a thicker neck circumference, smoking, nasal congestion, a family history of the condition, and drinking alcohol or taking sedatives.
For a February 2018 review of the literature published in the journal Sleep Medicine, researchers examined 21 studies about alcohol and OSA. The review concluded that people who drink alcohol have a 25% higher risk of obstructive sleep apnea than people who do not.
The authors of the study called for further research into the issue, noting that there are no randomized, controlled trials examining the connection between sleep apnea and alcohol intake. Furthermore, they said that how much alcohol you drink and what time you drink it are likely relevant to any increased risk of obstructive sleep apnea.
“It appears… likely that the timing and regularity of alcohol consumption are both important to the effect of alcohol on OSA, since airway muscle relaxation and reduced sensitivity to apnea are both likely to be greatest when alcohol levels are rising, as for example after bedtime consumption,” the authors wrote.
There are a number of treatments available for obstructive sleep apnea. One is a continuous positive airway pressure machine (CPAP), which is a mask you wear during sleep. “In this treatment, a machine delivers air pressure through a piece that fits into your nose or is placed over your nose and mouth while you sleep,” the Mayo Clinic says. Other treatment options include nasal masks and surgery to remove excess tissue.
If you are concerned that you may have obstructive sleep apnea, and that drinking alcohol worsens it, speak with your doctor about your worries. A physician can make a diagnosis and work with you on a treatment plan, which may or may not include cutting back on alcohol consumption.
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Alcohol Likely Interferes With REM Sleep
As mentioned earlier, the 2013 review of studies about alcohol and sleep found that alcohol reduces REM sleep. According to researchers, the level of interference depends on how much alcohol you’ve consumed. The study’s authors wrote: “The effects on rapid eye movement (REM) sleep in the first half of sleep appear to be dose-related with low and moderate doses showing no clear trend on REM sleep in the first half of the night whereas, at high doses, REM sleep reduction in the first part of sleep is significant. Total night REM sleep percentage is decreased in the majority of studies at moderate and high doses with no clear trend apparent at low doses.”
This matters because REM sleep is associated with learning and memory consolidation, and it’s considered incredibly important. As the Cleveland Clinic explains, there are two different sleep states: rapid eye movement sleep (REM) and non-rapid eye movement sleep (NREM). You cycle through sleep stages multiple times over the course of the night.
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NREM sleep happens first, and there are four different stages of NREM sleep. Stage 1 is the lightest sleep stage, and Stages 3 and 4 are deepest. After Stage 4 you move into REM sleep, usually about 90 minutes after you have fallen asleep. Your first period of REM sleep lasts about 10 minutes and gets increasingly longer as you move through sleep cycles during the night.
“REM sleep is a stage of sleep that is characterized by low muscle tone, rapid eye movements, and dreams,” the American Sleep Association says. “It is present in all mammals and has unique physiologic properties that distinguish it from non-REM sleep.”
According to the National Institute of Neurological Disorders and Stroke, your brain activity during REM sleep is “closer to that seen in wakefulness” and your heart rate and blood pressure “increase to near waking levels.” The institute says that successful memory consolidation probably requires a mixture of both REM and non-REM sleep.
Drinking Can Disrupt Brain Patterns
For a 2015 study, researchers looked at the brain activity of 24 healthy Australian subjects aged 18-21 on nights when they were given alcohol and orange juice before bed compared to nights when they received a placebo drink before bed. The subjects slept at the Melbourne School of Psychological Sciences Sleep Laboratory, where their brain activity during sleep was measured using an electroencephalogram (EEG).
The study found that, on nights where subjects had drunk alcohol, they experienced more slow-wave sleep patterns and something called delta activity, which is related to restoration and healing. But people in the study also had heightened alpha wave patterns at the same time as the delta wave patterns. Alpha waves are usually observed when someone is awake, but resting. These two types of waves occurring together can offset each other, causing less restful sleep. TIME reports: “In previous studies, such warring alpha-delta brain patterns during sleep have been linked to daytime drowsiness, waking up not feeling rested, and symptoms such as headaches and irritability.”
These results suggest potential long-term impacts. “Similar increases in alpha-delta activity, which are associated with poor or unrefreshing sleep and daytime function, have been observed in individuals with chronic pain conditions,” study author Christian L. Nicholas, National Health & Medical Research Council Peter Doherty Research Fellow in the Sleep Research Laboratory at The University of Melbourne, told Science Daily. “Thus, if sleep is being disrupted regularly by pre-sleep alcohol consumption, particularly over long periods of time, this could have significant detrimental effects on daytime wellbeing and neurocognitive function such as learning and memory processes.”
Alcohol Can Affect Your Dreams, Too
The Cleveland Clinic explains that alcohol is linked to experiencing vivid dreams or nightmares. According to BBC Science Focus, this happens because alcohol causes shallow sleep and more frequent wakeups — meaning you’re more likely to remember your dreams.
“Alcohol also similarly affects the body’s temperature; causing your body’s temperature to dip slightly, then rise, alcohol-spurned irregularities can contribute to nightmares the same way fevers do,” Medical Daily says.
Your dreams may also be affected when you give up drinking. If you are going through alcohol withdrawal — defined by MedLine Plus as “symptoms that may occur when a person who has been drinking too much alcohol on a regular basis suddenly stops drinking alcohol” — you can experience nightmares or vivid dreams. Withdrawal symptoms typically last for a few days but can stretch on for weeks in some cases.
Hangovers may interfere with sleep, too.
Drinking at nighttime isn’t the only thing that can affect your sleep when it comes to alcohol. If you experience a hangover, that can also affect how tired you feel and potentially interfere with your sleep schedule and energy levels.
According to the Mayo Clinic, fatigue is an extremely common hangover symptom that people experience after a bout of drinking. Other symptoms include:
- Excessive thirst
- Sensitivity to light and/or sound
- Poor or interrupted sleep
Increased fatigue from a hangover may prompt napping during the daytime, which could interfere with your ability to fall asleep and stay asleep that night. If you do feel hungover, Harvard Health says, make sure you drink plenty of water. The site also recommends drinking some coffee or tea for a jolt of caffeine, which can help combat fatigue and banish your grogginess.
When Should You Stop Drinking Before Bed?
There’s no singular, hard and fast rule about when you should stop drinking before bedtime — but experts agree that you should give yourself some time to metabolize drinks before going to bed for the night. One very general rule of thumb is to have your last alcoholic drink 2-3 hours before going to sleep in order to avoid alcohol-related sleep disruptions.
The time it takes your body to break down alcohol depends on a number of different things, including body weight, liver function, liver size, sex, and genetics. All of these factors help determine how much alcohol will intoxicate you, and also play a role in how quickly you can sober up after drinking.
If you metabolize alcohol very fast, you may find it no problem to have a drink much closer to bedtime. But generally speaking, while a nightcap may seem like a great idea to help you fall asleep, it may actually negatively affect your sleep over the course of the night. It’s best to give yourself a buffer between drinking and going to sleep whenever possible.
As part of a healthy sleep hygiene routine, plan to stop drinking at least 2 hours before you go to bed. This gives you plenty of time to complete your nighttime routine, which will help cue your body that it’s time to go to sleep. Options for a soothing bedtime routine include taking a warm bath, drinking a cup of herbal tea, reading, listening to music, meditating, or stretching. You should also avoid looking at electronic screens for an hour before bed, in order to facilitate the release of a hormone called melatonin that helps tell your body it’s time to sleep.
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Signs Your Sleep Is Taking A Hit
Sometimes it can be difficult to figure out what is causing various problems with your sleep. Plus, everyone handles alcohol differently, so some people may be seriously affected while others may not be.
One helpful tool is to track your sleep for a while and compare your sleep on nights when you have consumed alcohol to your sleep on nights when you have not. There are a number of available options for tracking your sleep. One option is a wearable sleep tracker, like one built into a smartwatch. These trackers use the accelerometer within the smartwatch to track when you are asleep, restless, and awake. They can also estimate how long you spend in different stages of sleep, though their accuracy is questionable — the only truly accurate way to measure sleep stages is using an EEG to track your brain waves.
Some smartphone apps can also track your sleep, for example when kept under your pillow or at the corner of your bed to record your physical movement during the night. And of course, there is always the good old-fashioned method of writing down any observations about your sleep when you wake up the next morning. You can note down your bedtime, what time you woke up in the morning, any times you woke up during the night, if you needed to go to the bathroom during the night, and anything unusual you remember about that night’s sleep.
Once you have been tracking your sleep for a while, you can compare your sleep on nights when you have consumed alcohol to nights when you have not. Do you sleep for longer or shorter when you have been drinking? Does your tracker estimate that you get less REM sleep? Do you note feeling groggier or more irritable the next day? The answers to these questions can help you gauge how alcohol affects your rest.
Alcohol Addiction And Sleep
Alcohol addiction is extremely common. The National Institute on Alcohol Abuse and Alcoholism (NIAAA) estimates that 6.2% of adults over 18 suffer from alcohol use disorder, defined as “a chronic relapsing brain disease characterized by an impaired ability to stop or control alcohol use despite adverse social, occupational, or health consequences.” The Mayo Clinic says that alcohol use disorder is “a pattern of alcohol use that involves problems controlling your drinking, being preoccupied with alcohol, continuing to use alcohol even when it causes problems, having to drink more to get the same effect, or having withdrawal symptoms when you rapidly decrease or stop drinking.”
According to the NIAAA, people suffering from alcohol use disorder may have a number of sleep issues. These include:
- Taking much longer to fall asleep
- Waking up more frequently
- Having more low-quality sleep, leading to an increase in daytime fatigue
These issues can continue even after someone with alcohol use disorder stops drinking alcohol. “Despite some improvement after withdrawal subsides, sleep patterns may never return to normal in those with alcoholism, even after years of abstinence,” the NIAAA says.
Some people with alcohol use disorder may need to undergo a detox, which can be very dangerous and is best done under the supervision of medical professionals. Some people with an alcohol addiction who give up drinking will go through withdrawal, described by Harvard Health as “the changes the body goes through when a person suddenly stops drinking after prolonged and heavy alcohol use.” Common alcohol withdrawal symptoms include tremors, anxiety, fatigue, nightmares, and insomnia.
MedLine Plus says that alcohol withdrawal symptoms typically peak within 24-72 hours, but can last for weeks in some instances. If you experience any long-lasting symptoms after quitting alcohol, speak to your doctor about what’s going on and what you can do about it.
The NIAAA stresses that alcohol use disorder can be successfully treated, no matter how severe the problem is or how long it has been going on for. Treatment options are far-ranging, from support through formal networks like Alcoholics Anonymous to in-patient programs, counseling, spiritual practices, and mental health treatments. If you believe you are suffering from alcohol use disorder, speak to a doctor about the best way to approach treatment.
The Bottom Line
Consuming alcohol can affect your sleep in a number of ways. It can shorten the time it takes you to fall asleep, shorten the duration of REM sleep, increase your risk of obstructive sleep apnea, contribute to nighttime wakeups, contribute to vivid dreams and nightmares, and play a role in daytime fatigue due to poor sleep and hangover symptoms.
It’s hard to say how much alcohol will affect any given person’s sleep, given that alcohol tolerance and metabolism vary greatly from person to person. One good rule of thumb is to stop drinking alcohol at least two hours before you go to bed each night. Tracking your sleep on nights when you drink and nights, when you do not drink, can help you figure out if alcohol is negatively affecting your sleep.
If you are suffering from alcohol use disorder, you are not alone. The condition can definitely affect your sleep by making it harder to fall asleep, contributing to frequent wakeups, and contributing to daytime fatigue. If you believe you are suffering from alcohol use disorder and want to seek help, you have plenty of options. You can speak to a physician about their recommended treatments, and approach a local support group or online network for important peer support. For more information, check out the resources listed below.
How Alcohol Affects the Quality—And Quantity—Of Sleep — National Sleep Foundation
Alcohol and Sleep — Drinkaware
Find Treatment — Substance Abuse and Mental Health Services Administration
Alcohol Use Disorder — Mayo Clinic
Alcohol and Fatigue — Harvard Health
Why You Should Limit Alcohol Before Bed for Better Sleep — Cleveland Clinic
Featured image: Syda Productions/Shutterstock
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