Alcohol and Sleep: The Truth Behind Your Nightcap

Alcohol and Sleep

Alcohol is the oldest and still one of the most widely used, mind-altering substances. It is so common and accepted in our culture that you may take it for granted. Yet, you might want to reconsider an evening cocktail if you take a closer look at the relationship between alcohol and sleep.

In this blog, part of our Mindful Drinking blog series, we explore the intricate relationship between alcohol consumption and sleep, delving into the impact of drinking on sleep quality, patterns, and overall well-being.

Table of Contents

How does alcohol affect sleep?
Alcohol and sleep quality
Risks of mixing alcohol and sleeping pills
Beyond the nightcap: alternatives for better sleep
Frequently asked questions

How does alcohol affect sleep?

Because alcohol depresses the central nervous system, many people associate it with a feeling of relaxation and stress relief. That same sedation can also lead to drowsiness. While you might fall asleep faster, the quality of sleep suffers.

The overall effects of alcohol on sleep depend on the individual's age, biological sex, weight, genetics, health history, and the amount of alcohol they've consumed. The U.S. Dietary Guidelines for Americans (Centers for Disease Control and Prevention, April 19, 2022) recommend that alcohol only be consumed in moderation and consider that to be:

Low amount of alcohol – less than 2 drinks for men, less than 1 drink for women
Moderate amount of alcohol – 2 drinks for men, 1 drink for women
High amount of alcohol – more than 2 drinks for men, more than 1 drink for women

During a restful night of sleep, a healthy individual falls asleep in 10 to 20 minutes, known as latency. Consuming alcohol reduces latency time because alcohol is a sedative (Colrain, I. M., Nicholas, C. L., & Baker, F. C., 2014). Due to that shortened time to fall asleep, many people believe a drink will help them get to sleep and have a better night’s sleep. An estimated 1 in 10 people use alcohol to induce sleep (Arnedt, J. T., Conroy, D. A., & Brower, K. J., 2007). +

Unfortunately for anyone using it to fall asleep, that’s only part of the effects of alcohol. As the body processes alcohol, depending on the volume consumed and the individual, it can negatively impact the beginning phases of sleep or the entire night.

Alcohol and sleep: a disrupted balance

As an individual falls asleep, they pass through four stages of sleep: two in the light sleep stage, one in deep sleep, and REM or Rapid Eye Movement. After the onset of sleep, there is a 90-minute cycle in which the individual moves through all four stages.

Depending on the duration of total sleep, there may be more or less of some stages in each 90-minute cycle. One major detrimental effect of alcohol on sleep is to disrupt the 90-minute sleep cycle. Depending on how much alcohol has been consumed, drinking just before bed can impact the first few hours of sleep.

Alcohol can suppress REM sleep for the first two 90-minute sleep cycles, affecting the balance of restorative sleep to less effective light sleep. The higher volume of light sleep can result in more sleep disturbances and less total sleep overall (Pietilä, et al., 2018).

NASM Better Than Fine podcast host Darlene Marshall is joined by Derek Brown, world-renowned mixologist and author of NASM's new Mindful Drinking course.

Alcohol and Sleep Quality: What You Need to Know

While alcohol can initially make someone sleepy, it compromises sleep quality. For those already having trouble sleeping, alcohol can exacerbate their problem.

Alcohol and sleep apnea

As a neurological depressant, alcohol can affect more than just sleep patterns in the brain. Obstructive sleep apnea is a sleep disorder where moments of hypopneas, periods when breathing is cut off and a person can’t get enough oxygen, occur. Hypopneas happen when something narrows the airway, such as large tonsils, poor anatomical alignment, or hormonal fluctuations.

Alcohol affects the body in various ways, including relaxing the structures at the back of the throat. For those with sleep apnea, drinking alcohol increases the frequency of hypopneas by almost 33 percent (Taveira, et al., 2018).

For those with sleep apnea who choose to drink, they can mitigate the effects by taking the following steps:

Stop drinking a few hours before bed to allow the body time to process the alcohol
Drink only low or moderate amounts of alcohol
Do not engage in binge drinking (3 or more drinks at a time)
Be evaluated and properly fit for a CPAP machine

2. Alcohol and insomnia

In the short term, individuals may use alcohol to self-medicate for insomnia, perpetuating an unhealthy cycle. The body first processes the alcohol and then the metabolic byproducts, along with any other ingredients in the beverage, such as sugar. Combined, these compounds drop blood sugar and affect sleep hormonal function, causing poor and/or disturbed sleep quality later in the night.

From that poor sleep, an individual can wake up groggy and dysregulate their normal circadian cycle. This dysregulated, natural 24-hour rhythm may make it more difficult to fall asleep at a healthy time. Perceiving insomnia, the habitual alcohol user has a drink to unwind, repeating the cycle. In this way, although alcohol makes you sleepy, it can cause insomnia and become a long-term self-perpetuating problem.

Risks of mixing sleeping pills and alcohol

Because alcohol is a sedative, similar to any sleeping medication, sleeping pills and alcohol is highly dangerous. Alcohol intensifies the sedative effects of sleeping medication. Mixing mild sleeping medication with alcohol can result in dizziness, disorientation, confusion, impaired cognitive function, and/or fainting. Stronger sleeping medications combined with alcohol can lead to slowed breathing and heart rate, causing the person to become unresponsive and potentially resulting in a health emergency.

Beyond the nightcap: alternatives for better sleep

There are many healthier alternatives that support a better night’s sleep:

Magnesium is an effective supplement to improve sleep quality by relaxing the central nervous system. Supplementing magnesium has been shown to effectively treat insomnia (Mah & Pitre, 2021)
Breathing techniques that relax the central nervous system can also be effective in the treatment of insomnia
You can access detailed recipes and instructional videos to help you craft deliciously sophisticated beverage alternatives to your nightcap in NASM's new Mindful Drinking course

Frequently asked questions (FAQs)

Will a small amount of alcohol affect my sleep?

Moderate amounts of alcohol right before bed delay the onset of REM sleep, affecting sleep balance. The exact amount and exact timing depend on your unique biology; however, it’s generally recommended to avoid alcohol in the last four hours before sleep.

Does alcohol help you sleep?

Alcohol does not help you sleep. Because alcohol is a sedative it may make it easier to fall asleep. Unfortunately, overall sleep quality is impaired, some functions of sleep are prevented, and it can cause insomnia later in the night.

What are other side effects of alcohol I should be aware of?

There are a variety of physiological and psychological effects of alcohol. According to the Center for Disease Control, they can be broken into both short-term and long-term effects:

Short-term:

Dehydration
Lowered inhibition
Increased depressive symptoms in following days
Learning and memory problems

Long-term:

Increased cancer risk
Increased blood pressure and risk of cardiovascular disease
Liver disease
Decreased immune system function and increased risk of illness
Increased risk of dementia

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References

Arnedt, J. T., Conroy, D. A., & Brower, K. J. (2007). Treatment options for sleep disturbances during alcohol recovery. Journal of addictive diseases, 26(4), 41-54.

Centers for Disease Control and Prevention. (2022, April 19). Alcohol questions and answers. Centers for Disease Control and Prevention. https://www.cdc.gov/alcohol/faqs.htm

Colrain, I. M., Nicholas, C. L., & Baker, F. C. (2014). Alcohol and the sleeping brain. Handbook of clinical neurology, 125, 415–431. https://doi.org/10.1016/B978-0-444-62619-6.00024-0

Mah, J., & Pitre, T. (2021). Oral magnesium supplementation for insomnia in older adults: a Systematic Review & Meta-Analysis. BMC complementary medicine and therapies, 21(1), 1-11.

Pietilä, J., Helander, E., Korhonen, I., Myllymäki, T., Kujala, U. M., & Lindholm, H. (2018). Acute Effect of Alcohol Intake on Cardiovascular Autonomic Regulation During the First Hours of Sleep in a Large Real-World Sample of Finnish Employees: Observational Study. JMIR mental health, 5(1), e23. https://doi.org/10.2196/mental.9519

Taveira, K. V. M., Kuntze, M. M., Berretta, F., de Souza, B. D. M., Godolfim, L. R., Demathe, T., ... & Porporatti, A. L. (2018). Association between obstructive sleep apnea and alcohol, caffeine and tobacco: A meta‐analysis. Journal of oral rehabilitation, 45(11), 890-902.