Alcohol and Sleep

Alcohol is the most popular sleep aid in the world. Though it may not be marketed as a sleep medication, at least 20 percent of Americans regularly use it as one. Even healthy people who don’t abuse alcohol may use it on occasion to fall asleep more quickly and easily — but that’s where the benefits end. While alcohol can help usher in sleep, it can also disrupt it.

“Alcohol is tricky. It’s great to fall asleep with,” says Dr. Shelby Harris, Sleepopolis’ director of sleep health. “But you’re falling asleep, and for what? To have poor quality sleep? That’s what the alcohol does. It wears off pretty quick, and when it wears off, it messes with the quality of sleep you have.” 

As Harris points out, nighttime awakenings, lower sleep quality, and reduced sleep efficiency are common side effects of consuming alcohol, even in moderate doses.

Most of us consider a drink or two to be safe, even healthy. But it doesn’t take much alcohol to change sleep patterns and have a detrimental impact on health.

Note: The content on Sleepopolis is meant to be informative in nature, but it shouldn’t take the place of medical advice and supervision from a trained professional. If you feel you may be suffering from any sleep disorder or medical condition, please see your healthcare provider immediately.

Alcohol and The Body

The type of alcohol used in beverages is called ethanol. (1) Ethanol is produced by the fermentation process of grains and fruits such as potatoes and grapes. Pure alcohol has no color, and converts to a sugar-based fuel inside the body. Alcohol depresses activity in the central nervous system, and is classed as a depressant drug.

Whether or not alcohol is dangerous to health may be dependent on dose. While moderate drinking may have physiological benefits as well as some potential drawbacks, chronic heavy consumption of alcohol can cause irreversible damage to the brain and body, including the circadian rhythm.

Moderate Alcohol Consumption

Consuming alcohol in moderate quantities — approximately one drink a day for women and two for men — can have varying effects on certain biological processes. Some studies show that moderate alcohol consumption can negatively impact the immune system.

For example, alcohol can negatively affect the gut’s microbiome, which may raise the risk of infection. (2) However, other studies have also shown that light to moderate drinkers may have reduced inflammation and improved responses to vaccination. (3)

Additionally, moderate alcohol consumption appears to have a beneficial or neutral impact on the cardiovascular system, including blood pressure and heart rate. It may also reduce the risk of stroke and diabetes. (4)

Moderate drinking can raise the risk of some cancers, including esophageal and breast cancer. (5) Even light drinking may have an effect on cancer risk due to alcohol’s ability to alter the mitochondria of cells. Mitochondria generate the energy used by cells, and may cause cell death or dysfunction when damaged.

Heavy Alcohol Consumption

Studies show that heavy drinking and binge drinking have a detrimental effect on all of the body’s systems, from immunity to blood pressure to liver function. (6) Heavy drinking is generally described as three or more standard drinks a day, while binge drinking is five or more.

There is no benefit to heavy drinking and binge drinking. (7) The International Agency for Research on Cancer states that alcohol and acetaldehyde, a byproduct of the breakdown of ethanol, can cause cancer when consumed in high amounts. Heavy drinking raises the risk of numerous health conditions, including:

• Accidents, including car accidents
• Certain cancers, including cancers of the colon and stomach
• Liver disease
• Brain damage
• Fetal alcohol syndrome
• Stroke
• High blood pressure
• Heart damage

The impact of alcohol abuse, also known as Alcohol Use Disorder (AUD), is both physical and psychological. Alcohol is strongly implicated in suicidal thoughts and behavior. Studies show that heavy drinkers have a five-fold increased risk of suicide, particularly among men. (8) In one study of suicide attempts, alcoholics were more likely to complete suicide than those who were not dependent drinkers.

Alcohol and Sleep

Anyone who has experienced a restless night after a few drinks can attest to alcohol’s disruptive effect on sleep. Studies prove that alcohol can reduce sleep quality, change sleep patterns, and reduce time spent in one sleep cycle while increasing time spent in another. Though alcohol can increase drowsiness and reduce the time it takes to fall asleep, drinking generally does not have a healthy influence on sleep efficiency or sleep-related bodily functions.

Drinking can disrupt the circadian rhythm, which controls the sleep and wake cycles as well as digestion, body temperature, and myriad other essential processes. Studies of alcohol consumption and sleep show that the body can develop tolerance to alcohol when drinking occurs over consecutive nights. Though the body may be successful in adapting to consistent alcohol use over the short-term and in rebalancing sleep patterns, it is unable to adjust sufficiently when alcohol consumption is heavy and chronic.

Alcohol impacts the way circadian genes express themselves by reducing levels of molecules that help to manufacture essential proteins. (9) Studies show that circadian rhythm genes may continue to display dysfunctional tendencies even after heavy drinking is stopped.

Once alcohol reaches the brain, it appears to mimic GABA, the predominant neurotransmitter of the circadian system. (10)  GABA also inhibits other neurotransmitters, preventing or delaying their primary functions. This inhibition can significantly slow down reactions and promote sleep during the early part of the night, but disrupt sleep cycles once the body metabolizes the alcohol and levels of GABA fall. (11) In addition to alcohol, GABA is impacted by drugs such as benzodiazepines and prescription sleep medications.

Moderate Alcohol Consumption and Sleep

Moderate Alcohol Consumption and Sleep

While the sleep-damaging effects of alcohol abuse are well-established, how does moderate drinking impact sleep? Research shows that the body metabolizes alcohol best during the “happy hour” of early evening. When consumed later at night, alcohol appears to shift sleep’s homeostasis — the balance between the need to sleep and wakefulness — to an earlier time of the evening. (12)

Moderate drinking can help reduce the time it takes to fall asleep, a period known as sleep latency. (13) In addition to its effect as a central nervous depressant, alcohol increases levels of adenosine, which blocks wakefulness-promoting cells in the basal forebrain. This process, as well as alcohol’s effect on GABA, may explain reduced sleep latency and the awakenings that can occur once levels of adenosine and GABA return to normal.

Moderate consumption of alcohol alters the orderly pattern and stages of healthy sleep, referred to as sleep architecture. Sleep is typically lighter and less efficient after drinking. Though more time may be spent in deep sleep during the first part of the night, time in REM sleep is reduced. The majority of dreaming occurs during REM sleep, as does the processing of emotions and memories. (14)

Decreased REM sleep can affect memory and potentially impact emotional responses during waking hours. (15) Noise, light, and other stimuli are more likely to cause awakening during REM sleep, which can increase daytime fatigue.

Once alcohol wears off, the body experiences a rebound effect. Sleep becomes lighter and less efficient, with more frequent awakenings. Though the disturbances to sleep have a significant impact on the body, not all awakenings will be noticed or remembered by the sleeper. Dehydration from alcohol may cause the heart to beat faster, making sleep more difficult.

Moderate drinking before bedtime can also increase the risk of the following:

• Parasomnias such as sleepwalking and sleep-eating (16)
• Sleep apnea and other sleep-related breathing disorders
• Waking to go to the bathroom
• Chronic insomnia due to negative psychological associations with the bed and sleep

Heavy Alcohol Consumption and Sleep

Heavy consumption of alcohol has damaging effects on the body and severely impacts sleep over time. Chronic heavy drinking can suppress REM sleep, while stopping alcohol can trigger a condition called REM sleep rebound. REM sleep rebound causes excessive dreaming, nightmares, and disturbed sleep, and may continue for weeks or months.

Long-term alcohol abuse causes changes to the brain that can result in persistent sleep disturbances, even with abstinence. Though insomnia is not the only sleep-related effect of alcohol abuse, the disorder may be to blame for 10 percent of all costs associated with excessive use of alcohol. (17)

In addition to its effect on the circadian rhythm and neurotransmitters, alcohol appears to influence the release of essential hormones. These include melatonin, a sleep-promoting hormone that is necessary for healthy sleep and wake cycles. Alcohol can also suppress growth hormone, which is important for proper immune function. Even in lower doses, alcohol reduces levels of testosterone, raises levels of estrogen, and changes the way the liver metabolizes hormones of all types.

Last Word From Sleepopolis

Alcohol is the most-consumed substance in the world, and is frequently used as a sleep aid. Alcohol may reduce sleep latency but disrupt sleep cycles and cause frequent awakenings during the night. (18)  Even moderate drinking can have a profound negative impact on sleep and the circadian rhythm.

Consuming alcohol early in the evening can help minimize but not eliminate the effect of alcohol on sleeping patterns. Sleep may be healthiest when not impacted by recreational  substances of any kind, including alcohol and caffeine. Trouble falling asleep is best addressed not by drinking, but by consultation with a sleep specialist who can help diagnose the issue and suggest healthy and effective treatments.

References

1. PubChem, Ethanol, U.S. National Library of Medicine, National Center for Biotechnology Information
2. Sarkar D, Jung MK, Wang HJ. Alcohol and the Immune System. Alcohol Res. 2015
3. Barr T, Helms C, Grant K, Messaoudi I. Opposing effects of alcohol on the immune system. Prog Neuropsychopharmacol Biol Psychiatry. 2016 Feb 
4. Gepner Y, Golan R, Harman-Boehm I, Henkin Y, Schwarzfuchs D, Shelef I, Durst R, Kovsan J, Bolotin A, Leitersdorf E, Shpitzen S, Balag S, Shemesh E, Witkow S, Tangi-Rosental O, Chassidim Y, Liberty IF, Sarusi B, Ben-Avraham S, Helander A, Ceglarek U, Stumvoll M, Blüher M, Thiery J, Rudich A, Stampfer MJ, Shai I., Effects of Initiating Moderate Alcohol Intake on Cardiometabolic Risk in Adults With Type 2 Diabetes: A 2-Year Randomized, Controlled Trial, Annals of Internal Medicine, Oct. 20, 2015
5. A. J. Tuyns, Epidemiology of Alcohol and Cancer, Cancer Research, July 1979
6. Popovici I, French MT., Binge Drinking and Sleep Problems among Young Adults, Drug and Alcohol Dependence, Sep. 1, 2013
7. Rehm J., The Risks Associated With Alcohol Use and Alcoholism, Alcohol Research Current Reviews, 2011
8. Pompili M, Serafini G, Innamorati M, Dominici G, Ferracuti S, Kotzalidis GD, Serra G, Girardi P, Janiri L, Tatarelli R, Sher L, Lester D., Suicidal Behavior and Alcohol Abuse, International Journal of Environmental Research and Public Health, Apr. 2010
9. Ming‐Chyi Huang, Reduced Expression of Circadian Clock Genes in Male Alcoholic Patients, Alcohol, Aug. 24, 2010
10. Davies M., The role of GABAA receptors in mediating the effects of alcohol in the central nervous system, Journal of Psychiatry and Neuroscience, July 2003
11. Gottesmann C., GABA mechanisms and sleep, Neuroscience, 2002
12. Tom Deboer, Sleep homeostasis and the circadian clock: Do the circadian pacemaker and the sleep homeostat influence each other’s functioning? Neurobiology of Sleep and Circadian Rhythms, June 2018
13. Kurt Kräuchi, Circadian Clues to Sleep Onset Mechanisms, Neuropsychopharmacology, Nov, 1, 2001
14. Groch S, Wilhelm I, Diekelmann S, Born J., The role of REM sleep in the processing of emotional memories: evidence from behavior and event-related potentials, Neurobiology of Learning and Memory, Jan. 2013
15. Els van der Helm, REM Sleep Depotentiates Amygdala Activity to Previous Emotional Experiences, Current Biology, Dec. 6, 2011
16. Rumbold JM, Riha RL, Morrison I., Alcohol and Non-Rapid Eye Movement Parasomnias: Where Is the Evidence? Journal of Clnical Sleep Medicine, Mar. 15, 2014
17. Kirk J. Brower, M.D., Alcohol’s Effects on Sleep in Alcoholics, National Institute on Alcohol Abuse and Alcoholism
18. Thakkar MM, Sharma R, Sahota P., Alcohol disrupts sleep homeostasis, Alcohol, June 2015