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How Does Alcohol Affect Sleep? Hint: They Don’t Mix Well

How Does Alcohol Affect Sleep? Hint: They Don’t Mix Well Image

“I need to drink to help me sleep,” someone may say. While alcohol relaxes the nervous system, in excessive amounts, it does the opposite. Those who drink alcohol before bed may be able to fall asleep, but then spend the night restless and unable to stay asleep. The next day, they may feel exhausted and hungover.

Normal Sleep Pattern

The human body is naturally programmed to sleep for restoration. Two interacting systems—the internal biological clock and the sleep-wake homeostat—determine the timing of sleep cycles. Once asleep, people naturally fall in and out of two types of sleep:

  • REM: rapid-eye movement sleep “active sleep” 
  • NREM: non-rapid eye-movement “slow-wave sleep”


Usually, REM sleep occurs 90 minutes after falling asleep. The first stage lasts around ten minutes, with each REM stage lengthening, and the final one lasting about an hour. NREM sleep consists of four stages, and each stage can last from 5-15 minutes.

During a good night’s sleep, the body cycles between NREM and REM sleep, although the majority of the cycle is spent in NREM sleep.

Both REM and NREM are needed for healing and rejuvenation. If someone does not get enough REM sleep, they may become confused, depressed, or irritable. On the other hand, if they do not get enough NREM sleep, they will feel tired, and their natural immunity will drop.

Alcohol Use and Sleep Patterns

Drinking alcohol before going to sleep is linked with slow-wave sleep patterns called delta activity. These high amplitude brain waves are measured during an electroencephalogram (EEG) and are known for producing deep sleep.

However, at the same time, another brain pattern, alpha activity, is activated.

The problem here is that alpha activity is not typically turned on during sleep, but rather when you’re resting with your eyes closed, but not sleeping. Because the brain shouldn’t produce alpha waves during sleep, this activity may prevent restorative sleep, interrupt the circadian rhythm, and block REM sleep.

Interrupts Circadian Rhythm

Alcohol is effective at suppressing melatonin, the body’s natural hormone that promotes sleep, and a key sleep regulator of sleep-wake cycles. Research shows that a moderate amount of alcohol up to an hour before bedtime can reduce melatonin production by nearly 20 percent.

The circadian rhythm is a 24-hour cycle controlled by the body’s biological clock. Circadian rhythms regulate all of the body’s processes, from cognitive functions to metabolism to sleep.

Alcohol disrupts circadian functioning by interfering with the ability of the biological clock to synchronize itself. Evidence also shows that alcohol elevates adenosine, a chemical that regulates sleep by rising naturally in the body the longer one has been awake while blocking other chemicals that stimulate wakefulness.

Blocks REM Sleep

In the first few hours after falling asleep, studies show that the body is metabolizing alcohol, causing people to spend time in NREM sleep and less time in REM sleep. Since REM sleep is vital for mental and emotional restoration, lacking this essential cycle will cause the person to feel disoriented, agitated, or depressed.

“Rebound Effect”

After alcohol is metabolized, the sedative effects diminish, and the body undergoes what scientists call “the rebound effect.” This means the body moves from deeper to lighter sleep, including restlessness and frequently waking up.

People then may wake up and not be able to fall back asleep, another consequence of the rebound effect.

Other Alcohol-Induced Sleep Problems

Other than the fact that the body cannot attain restorative sleep because of the disrupted circadian rhythm, many people experience these sleep disruptions:

  • Frequent trips to the bathroom
  • Increased risk of sleepwalking and sleep eating
  • Greater risk of snoring and sleep-disordered breathing
  • Trigger sleep disorders or worsen existing ones, like sleep apnea


Alcohol can induce Obstructive Sleep Apnea (OSA) or make the current condition much worse. Studies show that moderate or heavy drinking can cause episodes of OSA in those who don’t already have the condition.  Unfortunately for those who already have OSA, alcohol can increase the time in between when breathing stops and starts.

The Next Day after Alcohol-Induced Sleep

Research has shown that consuming alcohol before sleep may significantly reduce the duration and quality of sleep, and can impair performances the next day. This particular study used pilots as participants and found that those who drank alcohol the night before had a blood alcohol level of 100 mg per liter of blood, which is twice the United Nations’ legal driving limit.

The pilots’ performance on a flight simulator showed significant impairment, as well compared to those who had not consumed alcohol the night before.

It is safe to say that while alcohol may help someone fall asleep, they won’t be able to get restorative needed to feel refreshed and perform the next day’s activities well.

What About Those Who Suffer From Alcohol Addiction?

It is one thing to have a few nightly drinks before sleep and suffer from sleep disturbances, but alcohols suffer a magnified level of sleep problems. The National Institution of Health shows that sleep disorders are much more common among alcoholics than non-alcoholics.

In addition, the National Institution on Alcohol Abuse and Alcoholism states that during both drinking periods and withdrawal, alcoholics commonly experience problems falling asleep, staying asleep, and getting REM sleep.

Another problem is that even after an alcoholic stops drinking, they still may experience sleep-related disturbances in recovery for months or even years.

The Bottom Line

The bottom line is that alcohol negatively impacts sleep, whether someone has an alcohol problem or not. Either cutting back or quitting altogether will bring you the restorative sleep your body needs. The good news is that normal sleep patterns can occur after periods of sobriety.

If you are addicted to alcohol and need help, please reach out. You are not alone.

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Adam Nesenhoff

Adam Nesenhoff has been working in recovery for over ten years.

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