Alcohol and Sleep - How that drink before bed affects your sleep

Introduction

Why alcohol and sleep don’t mix… For many, a nightcap seems like the perfect way to unwind after a long day and help you fall asleep faster. However, while alcohol may initially make you feel drowsy, it can significantly interfere with your sleep cycle and the overall quality of your rest in a variety of ways that we’ll look at in detail.

The Myth of the Nightcap

One of the most prevalent and long-standing myths surrounding alcohol, sleep – and particularly insomnia – is the idea that a drink before bed can help you fall asleep faster, thus reducing insomnia.

“There was a notion in the alcohol field that moderate drinking was good for you and had some health benefits,” says Ian Colrain, president and CEO of MRI Global—a research institute based in Kansas City, Missouri—who has published research about insomnia and alcohol consumption before sleep. “Recently that guidance has changed. There are no real health benefits overall of drinking.” And that’s true even when it comes to trying to combat insomnia. [2]

Alcohol and the Sleep Cycle

To understand why alcohol before bed is detrimental to your sleep, it’s essential to know a bit about the sleep cycle. A typical sleep cycle consists of different stages [1], including:

Stage 1 (Light Sleep): This is the transition from wakefulness to sleep.
Stage 2 (Deeper Sleep): Your body temperature and heart rate drop.
Stage 3 (Deep/Slow-Wave Sleep): This is the most restorative phase, crucial for physical and mental restoration.
Stage 4 REM Sleep (Rapid Eye Movement): This is when most of your dreaming occurs and plays a role in memory consolidation. While stage 4 and REM sleep are sometimes referred to as being the same, stage 4 can also have characteristics of deep sleep or delta sleep, but without rapid eye movements, or “stage 4 NREM”.

The 4 ways alcohol disrupts your natural sleep cycle:

1 – Reduced REM Sleep:

Alcohol reduces the time spent in REM sleep, which is essential for cognitive function and emotional well-being. This can lead to grogginess and a lack of mental clarity the next day.

REM Sleep Overview:
REM sleep is one of the four stages of the sleep cycle. It is characterized by rapid eye movement, increased brain activity, vivid dreams, and muscle paralysis. REM sleep is crucial for various functions, including memory consolidation, emotional processing, and overall mental well-being.
Alcohol’s Impact on REM Sleep:
While alcohol can make you feel drowsy and help you fall asleep faster, it has a negative impact on REM sleep. Research has shown that alcohol consumption before bedtime often leads to a reduction in REM sleep time during the first half of the night. As a result, you may spend less time in this crucial stage of sleep and you’ll end up with a more fragmented, worse night’s sleep than if you had skipped that drink. [2]
REM Rebound Effect:
Interestingly, alcohol consumption can also lead to a phenomenon known as the “REM rebound effect.” This occurs when your body compensates for the initial reduction in REM sleep by increasing the proportion of REM sleep during the latter part of the night. While this might seem beneficial, the fragmented sleep patterns caused by alcohol disrupt the continuity of REM sleep, making it less restorative. [2]
Vivid Dreams and Nightmares
Alcohol can also lead to more vivid and intense dreams, including nightmares. These dreams often occur during the later part of the night when the REM rebound effect takes place. This increased dream activity contributes to poor sleep quality and can cause you to awaken.
Cognitive Impact
Reduced or disrupted REM and non-REM sleep patterns have been shown to be associated with cognitive deficits, including impaired memory, concentration, problem-solving abilities and possibly increased risk of Alzheimer’s disease. [5] It can also affect mood, leading to irritability and decreased emotional well-being.
Alcohol Tolerance
Over time, the body may develop tolerance to the sleep-inducing effects of alcohol, but the negative impact on REM sleep remains. This means that even if you’ve built up a tolerance to the initial sedative effects of alcohol, it can still disrupt your REM sleep.
Alcohol Withdrawal
It’s important to note that alcohol is a psychoactive drug. As with any such drug, dependency and withdrawal can occur if you’re accustomed to drinking regularly, and can lead to sleep disturbances as well. Insomnia and a rebound in REM sleep can occur during withdrawal, further impacting sleep patterns.

In summary, while alcohol may initially make you feel drowsy and help you fall asleep, it leads to a reduction in REM sleep during the first half of the night and can disrupt the continuity and quality of your rest. Over time, this can result in cognitive deficits up to and including Alzheimer’s, and impact your overall well-being. [4]

2 – Fragmented Sleep:

While it may initially make you feel drowsy and facilitate the onset of sleep, alcohol can lead to fragmented and disrupted sleep throughout the night. Here’s how:

Increased Wakefulness
Alcohol can increase your number of awakenings during the night. These awakenings may not always lead to full consciousness, but they can be enough to disrupt the natural sleep cycle, preventing you from achieving the deep, restorative sleep your body needs.
Altered Sleep Architecture
Alcohol can alter the balance between sleep stages, particularly by reducing – or disrupting the proper balance of – the times spent in the deeper stages and REM sleep. This can lead to an uneven distribution of these sleep stages (you’ll see this referred to as “sleep architecture”), contributing to fragmented sleep.
Rebound Effects
After the initial sedative effects of alcohol wear off, the body may experience a “rebound” effect. As blood alcohol levels decline, there can be increased brain activity and alertness, leading to awakenings. This often occurs during the second half of the night, disrupting the continuity of sleep.
Night Sweats and Discomfort
Alcohol can cause physiological changes, such as night sweats and increased body temperature, leading to discomfort during the night. These physical discomforts can trigger awakenings, making it difficult to maintain a continuous and restful sleep.
Increased Risk of Sleep Disorders
Alcohol consumption can exacerbate sleep disorders like snoring and sleep apnea (discussed in more detail below), which can result in frequent awakenings and disrupted sleep.
Digestive Issues
Alcohol can irritate the stomach and relax the lower esophageal sphincter (where the esophagus empties into the stomach…or sometimes vice versa), leading to acid reflux and heartburn. These gastrointestinal symptoms can disturb sleep, trigger night sweats and cause awakenings due to discomfort.
Impact on Sleep Patterns
When alcohol disrupts the sleep cycle, it can lead to a state of “non-restorative” sleep. Even if you spend the recommended number of hours in bed, the frequent interruptions mean you may not achieve the necessary restorative sleep, leaving you feeling fatigued the next day.
Impaired Cognitive Function
Fragmented sleep impairs cognitive function, affecting memory, concentration, and problem-solving abilities. This can lead to decreased productivity and increased daytime drowsiness. Importantly, this is one of the many factors that can contribute to the development of Alzheimer’s.

3 – Worsening of Sleep Apnea:

Alcohol can relax the muscles in your throat, increasing the likelihood of snoring and obstructive sleep apnea.[6] The relationship between alcohol, sleep, and sleep apnea is a complex one. It’s important to understand how alcohol can influence sleep apnea, a condition characterized by pauses in breathing during sleep.

Here’s a closer look at this relationship:

Muscle Relaxation
Alcohol is a muscle relaxant, and it can lead to increased relaxation of the muscles in your throat and airway. This relaxation can exacerbate the underlying issue in obstructive sleep apnea (OSA), where the throat muscles collapse and block the upper airway during sleep. When these muscles become even further relaxed due to alcohol consumption, the likelihood of snoring and experiencing apnea episodes increases.
Increased Apnea Events
The relaxation of the throat muscles caused by alcohol can lead to more frequent apnea events. In individuals with OSA, these events can range from brief awakenings to extended periods of oxygen deprivation. The increased frequency of apnea events can significantly disrupt the sleep cycle, making it difficult to achieve restorative sleep.
Arousal Response
Alcohol can also affect the body’s ability to respond to apnea events. Normally, when the body detects a drop in oxygen levels or an increase in carbon dioxide, it triggers an arousal response to wake you up and restore normal breathing. However, alcohol can blunt this response, making it less effective in people with sleep apnea. As a result, they may experience longer and more severe apnea episodes without waking up to correct the issue.
Snoring
Snoring is a common symptom of both sleep apnea and alcohol consumption. Snoring is often made worse by alcohol due to the relaxation of the throat muscles. Loud snoring can disrupt your sleep and the sleep of those around you. Note: even in the absence of alcohol consumption, snoring is usually a sign of a sleep breathing disorder.

It’s worth noting that while alcohol can exacerbate sleep apnea, it’s not the cause of the condition. Sleep apnea has several risk factors such as obesity, family history, and structural issues in the upper airway. However, alcohol can significantly worsen the symptoms and complications of sleep apnea.

Note: If you have – or suspect you may have – sleep apnea, it’s advisable to limit alcohol consumption, particularly in the evening hours. Sleep apnea is a serious, life threatening condition if not treated. If you have been told you have sleep apnea – or if you snore – a consultation with a sleep physician, or other qualified sleep clinician – is imperative.

4 – Night Sweats:

Alcohol can cause both night sweats and hot flashes, leading to discomfort and further sleep disturbances in several ways, as outlined below.

Thermoregulation:
Alcohol consumption can disrupt the body’s ability to regulate temperature effectively. It has a vasodilating effect, meaning it causes blood vessels to expand, leading to increased blood flow to the skin’s surface. This can make you feel warmer and trigger sweating as your body attempts to cool down.
Dehydration:
Alcohol is a diuretic, meaning it increases urine production. This can lead to dehydration, which, in turn, affects your body’s ability to cool down through sweating. Dehydration can make you more susceptible to overheating and night sweats.
Alcohol Withdrawal:
As I mentioned earlier, for individuals who consume alcohol regularly (and thus develop at least some degree of dependence on it), night sweats can be a symptom of alcohol withdrawal. When you’ve become dependent on alcohol, your body adapts to its presence. When you stop drinking, that can lead to withdrawal symptoms, including night sweats, as your body readjusts to functioning without alcohol. The psychological effects of alcohol withdrawal can also be unpleasant, and further contribute to sleep disruption.
Nighttime Blood Sugar Fluctuations:
Alcohol can affect blood sugar levels. When your blood sugar drops, it can trigger your body to release stress hormones. This can lead to increased heart rate, night sweats, and discomfort.
Alcohol-Induced Hormonal Changes:
Alcohol can affect the body’s hormone balance, including changes in levels of cortisol and adrenaline, both of which are associated with increased sweating. Hormonal changes associated with the onset of menopause are also associated with, and can worsen, hot flashes. These are similar to, but not the same as, night sweats but both are adversely affected by alcohol consumption. [7]
Increased Heart Rate:
Alcohol can lead to an increased heart rate and changes in heart rhythm, even when as little as one glass of wine or one drink is consumed. [3]
Metabolism of Alcohol:
The body metabolizes alcohol primarily in the liver. As the liver processes alcohol, it can generate heat. This contributes to the sensation of being overheated.

Understanding this connection is crucial for those who experience excessive sweating or hot flashes during the night after alcohol consumption. [7]

Note to Anyone with a Heart Condition: Your doctor may have already told you to avoid alcohol, especially before bed. There are numerous studies that illustrate multiple cardiac dangers posed by alcohol, especially those that occur during sleep.

It’s important to recognize that not everyone who consumes alcohol will experience night sweats. The degree of sweating can vary from person to person. Factors such as the amount of alcohol consumed, individual tolerance, overall health, and genetic predisposition can influence the likelihood and severity of night sweats.

If you regularly experience night sweats after alcohol consumption, it may be a sign that your body is reacting negatively to alcohol. So, it’s advisable to moderate your drinking or seek guidance from a healthcare professional. Reducing alcohol intake, drinking plenty of water, and practicing good sleep hygiene can also help minimize the risk of night sweats related to alcohol.

Conclusion

The myth of the effectiveness of alcohol used as a sleep aid before bed is just that – a myth. If you want to have healthy, good quality sleep, alcohol and sleep simply don’t mix – ever.

While alcohol may initially make you feel drowsy, it disrupts the natural sleep cycle and reduces the quality of your sleep. For good sleep, be aware of the impact of alcohol on your sleep patterns and consider alternative relaxation methods. Try things like meditation or other focused relaxation techniques – to ensure a good night’s rest.

The effects of alcohol on sleep vary from person to person. This depends on factors like the amount and timing of alcohol consumption, individual tolerance, and overall health. Some people may be more sensitive than others to alcohol’s disruptive effects on sleep.

As with addressing any disorder or unbalance in your body, getting to the root cause of why you’re having trouble sleeping – by prioritizing healthy sleep habits and a consistent sleep schedule – is crucial for overall well-being and optimal cognitive function.

So, when it comes to getting a good night’s sleep, skip the drink and reach for a book or a warm cup of milk or herbal tea instead. [2] And, please see a sleep specialist if you still have problems sleeping that are NOT alcohol-related.