Effects of Alcohol on Sleep

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It is a well-established fact that adequate sleep is essential for overall health and wellness. Healthy sleep patterns help improve learning, memory, and mood. It also has positive implications for immunity.

Developing healthy sleep habits is sometimes referred to as sleep hygiene. While developing consistent sleep habits is essential for impacting sleep health for the better, some habits can negatively impact your sleep health.

Is Healthy Sleep Important?

Most people understand the importance of a balanced diet and regular exercise when it comes to health and wellness. However, getting adequate sleep is often overlooked. Healthy sleep is equally as important as diet and exercise, and it comes with its own health benefits.

According to sleep studies, inadequate sleep can have some poor effects on your health as it can interrupt some important processes within the body.

Immune Health

Poor sleep can disrupt the body’s normal immune function. During sleep, chemical messengers known as cytokines are released. These are essential for proper immune function. After all, poor sleep can interrupt this process.

Metabolic Health

Poor sleep can also disrupt normal metabolic function, which could contribute to metabolic disorders.

Memory and Mood

Many people have experienced the dreaded “brain fog” that is associated with poor sleep. A lack of sleep can have a serious impact on mental clarity, mood, and overall cognition.

Sleep Stages and Alcohol

When you sleep, your body goes through a sleep cycle. The sleep cycle is made up of four distinct sleep stages. The average person progresses through the four sleep stages about four to six times on a typical night. Sleep disorders like sleep apnea or insomnia can disrupt this normal process.

The four sleep stages are made up of three non-rapid eye movement (NREM) stages and one rapid eye movement (REM) stage.

  • Stage 1 - This initial stage of NREM sleep is when your body begins to shut down and transitions from wakefulness to sleep. Breathing, heart rate, and eye movements start to slow down while muscles relax and brain activity decreases.
  • Stage 2 – During the second stage of NREM sleep, which is typically the longest stage, the breathing and heart rate continues to decrease as sleep gets deeper. Also, the body temperature will decrease slightly and eye movement becomes virtually still.
  • Stage 3 – In the third stage of NREM — also known as slow-wave sleep — breathing, heart rates, and brain activity are at their lowest levels. Eye movement has ceased and muscles are completely relaxed.
  • Stage 4 – REM sleep typically occurs about 90 minutes after falling asleep. Breathing and heart rate increase slightly and eye movements will restart. This is the stage where dreaming occurs. This stage also plays a vital role in the memory processes.

Alcohol’s Effect on Sleep

Deciding to drink alcohol occasionally will not adversely affect most adults. In fact, some people believe there could actually be some benefits from the occasional glass of wine. However, “less is more” is the general rule when it comes to alcohol, and binge drinking generally isn’t beneficial for anyone.

But how does alcohol relate to sleep?

Alcohol is considered a central nervous system (CNS) depressant. In short, its sedative effects cause brain activity to slow down, which can lead to feelings of relaxation. Since alcohol has the ability to induce relaxation, many believe it has a positive effect on sleep.

But there is much more to it than that. A nightcap before bed may certainly induce the feeling of sleepiness in the first half of the night. Still, research shows it might actually disturb sleep in the second half of the night, later within the sleep cycle — or exacerbate existing sleep issues like obstructive sleep apnea.

The relationship between alcohol and sleep has been studied for decades. While the full extent of the relationship is not fully known, research has found that heavy drinking before bed can increase sleep onset latency.

Alcohol and REM sleep stage

As your liver enzymes work to metabolize the alcohol during the night, it can actually cause disruptions in deep sleep and drive down overall sleep quality. Alcohol can also suppress REM sleep during the first few sleep cycles.

In short, this can create an imbalance in the sleep-wake cycle, resulting in a decrease in sleep quality, an increase in daytime sleepiness, and an increase in sleep disruptions like frequent awakenings and sleepwalking.

Alcohol’s Effects on Sleep Disorders

Alcohol use before bed can also exacerbate certain sleep disorders. For example, insomnia is a common sleep disorder that is marked by an inability or persistent difficulty with falling or staying asleep.

Since alcohol affects the body by suppressing the REM stage, leading to sleep disruptions, it can also worsen existing symptoms of sleep difficulty.

Sleep apnea is another sleep disorder marked by abnormal breathing patterns or the temporary absence of breathing during the night. This disorder often leads to poor sleep quality. Studies have shown that consuming alcohol actually increases the risk of sleep apnea by roughly 25 percent.

In addition to the impact of alcohol on these sleep disorders, alcohol can also disrupt the normal processes of a circadian rhythm regulatory hormone known as melatonin by suppressing its effects. A supplemental melatonin sleep aid and alcohol should never be taken together.


Quality sleep is extremely important to overall health and wellness. Developing healthy sleep habits is just as important as a balanced diet and regular exercise.

Although drinking alcohol in proper moderation is typically safe for most people, it may not be the best thing to do before bedtime. It should be avoided before bedtime to ensure restful sleep.

While it’s true the night cap could help lead to drowsiness and relaxation at bedtime, it can also disrupt the sleep cycle and cause restlessness later into the night, leading to poor sleep quality overall.


Sleep: a health imperative | NIH

Stages of Sleep | Sleep Foundation

Disturbed Sleep and Its Relationship to Alcohol Use | NIH

Sleep, Sleepiness, and Alcohol Use | NIAAA

Alcohol and the risk of sleep apnoea: a systematic review and meta-analysis | NIH

Healthy Directions Staff Editor