You know that woozy boozy feeling you get after a certain number of cocktails, the one that makes you feel like you could fall fast asleep for the whole night? It’s a ruse.
Does alcohol make you sleep better? No. It may make you fall asleep initially, but it is definitely not a viable sleep aid. In fact, after it sedates you into slumber, alcohol produces highly fragmented, non-restorative "manufactured" sleep. With that kind of interrupted sleep, it’s almost impossible to meet your sleep need. And depriving yourself of the sleep your body needs leads to low energy and impaired functioning even after you sober up the next day.
In this article, we’ll bust some common myths and uncover a few sobering truths about how alcohol affects your sleep. If you value a good night’s sleep and want to perform at your best during the day, it might be time to nix that nightcap.
No one is saying your favorite wine or cocktail doesn’t have a relaxing effect. Alcohol is indeed a sedative. It’s classified as a central nervous system depressant because it slows brain function, mostly via gamma-aminobutyric acid (GABA), a neurotransmitter that produces a calming effect. As alcohol increases GABA activity in the brain, you may start to feel sleepy. But after you doze off, alcohol actually disrupts your sleep.
When you drink alcohol at night, you’re more likely to sleep fitfully or awaken during dreams, especially during the second half of the night when alcohol’s sedative effects have worn off. Sometimes this sleep fragmentation can go undetected by the sleeper, further enforcing the false notion that alcohol helps you sleep well.
To understand how alcohol disrupts your sleep, let’s take a quick look at how the four stages of sleep fit into a sleep cycle. Normal sleep cycles last about 90-120 minutes each, and you may have four or five cycles each night. Within each cycle, your body moves through four different stages of sleep. Stages 1, 2, and 3 are NREM (non-rapid eye movement) sleep, and stage 4 is REM (rapid eye movement) sleep.
Stage 1 is dozing and transitory, light sleep where your heartbeat, breathing, eye movements, and brain waves begin to slow. In stage 2, things slow down even more; muscles relax, body temperature drops, and your eyes become still.
Stage 3 — often called slow-wave or delta sleep — is deep, restorative sleep. Heart rate, breathing, and brain activity reach their lowest levels. In REM or stage 4, breathing and heart rate quicken, and eye movement starts back up. Most dreaming and memory consolidation happen during stage 4.
The problem with alcohol is as the body processes it during the first half of the night, you reach stage 3 more quickly, but at the expense of REM sleep. During the second half of the night, once the alcohol has been processed, you experience "REM rebound" where REM sleep increases in a bid to catch up and maintain your normal sleep patterns, but this usually disrupts your natural waking process.
If your favorite drink is a bloody mary or mimosa over brunch, the good news is that’s the best time of day to be drinking. Drinking later in the day is problematic for sleep, significantly reducing the amount of REM sleep we get at night.
In his book Why We Sleep Walker explains:
“Alcohol is one of the most powerful suppressors of REM sleep that we know of. When the body metabolizes alcohol it produces by-product chemicals called aldehydes and ketones. The aldehydes in particular will block the brain’s ability to generate REM sleep. It’s rather like the cerebral version of cardiac arrest, preventing the pulsation beat of brain waves that otherwise power dream sleep. People consuming even moderate amounts of alcohol in the afternoon and/or evening are thus depriving themselves of dream sleep.”
The negative effects of alcohol also include hindering our ability to retain what we learn. Because alcohol interferes with REM sleep, it can also make you forget new information, even if the drinking happens days after the learning took place. A 2003 study found that memories remain very vulnerable to sleep disruption from alcohol, despite two full nights of natural sleep between the learning and the drinking.
Sleepwaking (somnambulism) and sleep talking (somniloquy) are slow wave sleep disorders (SWSD), disorders that cause unwanted nocturnal behaviors, and both may be triggered by alcohol. Sleep talking, which afflicts 5% of adults, has no medical significance and requires no treatment. Although the sleep talker’s partner whose sleep is interrupted by the in-bed speech may be the one who suffers most!
Sleepwalking is much more dangerous, since there can be many potential hazards in the sleepwalker’s path — stairs, open windows, sharp objects, etc. Incidents of “sleepdriving” are perhaps the most serious as they can endanger dozens or hundreds of other people.
The causes of somnambulism are not fully understood, but alcohol is suspected to be among them. There is no known cure, but episodes become less frequent with age. Only 2-4% of adults sleepwalk, possibly because people experience less deep sleep as they get older.
If a few glasses of wine at happy hour send you to the restroom more than once, you probably already know alcohol is a diuretic. And urinary frequency can extend past your bedtime. Each time you get up to use the bathroom at night is an interruption of your sleep, and it’s not always easy to fall back asleep immediately.
Alcohol can further disrupt and fragment sleep by triggering snoring and sleep apnea. Consuming alcohol close to bedtime can cause or worsen snoring, because alcohol relaxes muscles in the throat thereby decreasing your body’s natural defenses against airway obstruction. And alcohol consumption produces the lowest oxygen saturation levels in patients at risk for or suffering with sleep apnea or obstructive sleep apnea.
For women experiencing menopause, alcohol can trigger hot flashes which at night-time can be incredibly disruptive to sleep. Research shows daily alcohol consumption significantly increases the risk of hot flashes and night sweats.
One of the most alarming effects of alcohol involves babies born to mothers who are alcoholics or heavy drinkers during pregnancy. Newborn sleep disruption was one of the first problems studied by researchers investigating fetal alcohol syndrome in the 1970s.
When compared to babies whose mothers did not drink during pregnancy, infants with fetal alcohol syndrome “had difficulty reaching a NREM episode without waking first, exhibited more arousals during both REM and NREM sleep, and had fewer intact REM/NREM cycles.”
The miserable feelings associated with an alcohol hangover are often caused or worsened by short sleep duration. Heavy drinking in the evening is associated with sleep loss that night as well as daytime sleepiness, reduced activity levels, and impaired performance the next day.
Defined as five or more drinks in a row for men and four or more drinks in a row for women, binge drinking on a weekly basis can have a significant negative impact on sleep. According to a 2013 study: “The detrimental effects on sleep increase in magnitude with frequency of binge drinking, suggesting a dose-response relationship. Moreover, binge drinking is associated with sleep problems independent of psychiatric conditions.”
Roughly 35% to 70% of people who suffer from alcohol use disorder — a medical diagnosis for varying degrees of alcohol problems or dependence — report having insomnia or trouble sleeping.
A 2018 study by sleep medicine specialist Dr. Timothy Roehrs, director of research at the Sleep Disorders and Research Center at Henry Ford Hospital, found people who drink alcohol before bed to hasten sleep onset often develop a tolerance that prompts them to escalate the dose. Repeatedly increasing the amount of alcohol intake can lead to alcohol dependency or addiction. And the sleep problems associated with full blown alcoholism are even more severe.
Alcoholics with a pent-up need for REM/dream sleep can sometimes experience aggressive intrusions of dreaming while wide awake. This terrifying psychotic state called delirium tremens is a symptom of alcohol withdrawal that often starts when the alcohol-addicted person seeks treatment and has just begun to detox. Symptoms include shaking, fever, confusion, hallucinations, and high blood pressure. For some, delirium tremens is fatal.
It’s clear that alcohol’s sedative effects are temporary, and drinking it before bed as a “sleep aid” will backfire. Not only will you get less sleep and miss out on the restorative power of REM sleep, but you’ll also put yourself at risk for some of the other side effects discussed in this article.
Alcohol’s effect on sleep varies depending on how close to bedtime you consume it. At Rise Science, we recommend setting a cutoff time that falls at least three to four hours before your bedtime. The RISE app includes an option to send yourself a daily reminder of this cutoff time. We also suggest limiting your drinks to a maximum of one to two per day, preferably consumed with a meal.
To consistently get the hours of sleep you need at night to have optimal energy in the daytime, you need good sleeping habits. Being strategic about the timing of your alcohol consumption is an important part of sleep hygiene, the upkeep of behaviors that affect the way you sleep. Download the RISE app to start improving your sleep hygiene habits today.
You don’t necessarily have to forgo alcohol altogether. Giving up nightcaps in favor of a cocktail at happy hour is a step in the right direction. Day drinking is even better. 🙂
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