WHY DOES ALCOHOL MAKE ME SLEEPY? EXPLORING THE SCIENCE BEHIND DROWSINESS

Alcohol may make you tired, but it does not cause good sleep

Many people experience a wave of sleepiness after consuming alcohol. As a central nervous system (CNS) depressant, alcohol has a sedative effect that may cause you to fall asleep more quickly than usual. However, the initial drowsiness alcohol causes can be deceiving. Alcohol disrupts sleep quality throughout the night, leading to less restful and restorative sleep. 

This article discusses the science behind why alcohol makes you sleepy, how to minimize drowsiness while drinking, and the broader effects alcohol has on your sleep and overall health. 

Why Alcohol Makes You Sleepy

By depressing the central nervous system, alcohol reduces the brain's ability to process information and respond to stimuli. This depressant effect is why many people experience a sense of relaxation and reduced anxiety after a few drinks. Once the body's systems slow down, this can quickly turn into drowsiness. Here's how it works: 

When you drink alcohol, it's absorbed through the stomach and small intestine and moves into your bloodstream. Once in the bloodstream, alcohol reaches your brain within minutes, where it interacts with various neurotransmitters — chemical messengers that send signals to neurons throughout your body and control your behaviors, thoughts, and feelings. 

Alcohol primarily interacts with two important neurotransmitters—gamma-aminobutyric acid (GABA) and glutamate—as follows: 

• GABA is a neurotransmitter that calms the CNS and slows down signals from other neurotransmitters to help your brain process information at a reasonable pace. Alcohol enhances the effects of GABA, slowing down communication between brain cells, which translates to a feeling of relaxation and calmness. 
• Glutamate is a neurotransmitter that promotes communication between brain cells and plays a role in nearly every body function, including learning, memory, and mood. Alcohol reduces glutamate actions, contributing to the overall slowdown of brain activity. 

The effects of alcohol on these neurotransmitters is sedative, which is why alcohol initially makes you relaxed and drowsy and may help you fall asleep more easily. 

Why Alcohol Also Keeps You Up

While alcohol initially induces drowsiness, it ultimately disrupts normal sleep patterns, leading to a night of fragmented and unrefreshing sleep. Here's how alcohol interferes with your sleep cycle:

Reduces REM Sleep

Alcohol significantly affects rapid eye movement (REM) sleep, a vital sleep stage for cognitive functions like memory consolidation, learning, and emotional regulation. Alcohol suppresses REM sleep, particularly during the first half of the night, reducing the amount of time you spend in this restorative sleep phase. Reduced REM sleep can leave you with brain fog and fatigue the following day. 

Disrupts the Sleep Cycle

Alcohol disrupts the natural cycle of sleep stages, which typically alternates between non-REM and REM sleep every 80 to 100 minutes, between four and six times a night. After a night of drinking, you may enter a deeper sleep than usual as soon as you fall asleep and spend less time in REM sleep. As the night wears on, you experience less deep sleep and more light sleep, leading to sleep disturbances and poor-quality sleep. 

Causes Night Awakenings and Frequent Urination

Alcohol is a diuretic, meaning it increases urine production, leading to more frequent bathroom trips throughout the night and fragmented sleep. The diuretic effects of alcohol increase as your blood alcohol concentration rises, meaning the more you drink, the more you'll wake up at night to pee. Alcohol's diuretic effects can also contribute to dehydration, as your body expels fluids faster than you replace them.

Promotes Vivid Dreams

Drinking alcohol before bedtime may cause more vivid, sometimes unpleasant dreams.

Research shows that alcohol consumption is associated with more action-filled, aggressive dreams. Because alcohol suppresses REM sleep in the first half of the night, people tend to have more REM sleep in the later part of the night (REM rebound), which may lead to more vivid and bizarre dreams and more frequent wakings that increase dream recall.

Other Negative Effects of Alcohol on Your Sleep

Beyond causing drowsiness and sleep disruptions, alcohol can have other adverse effects on your sleep quality. 

Leads to Insomnia

Research shows alcohol consumption can cause or worsen insomnia, a sleep disorder that causes problems falling or staying asleep. While alcohol may initially help you fall asleep, as the night progresses and your body metabolizes the alcohol, you may experience disruptions in the sleep cycle and have trouble falling back asleep later in the night.

Long-term moderate to heavy alcohol consumption is associated with high rates of insomnia, with up to 76% of people with alcohol use disorder experiencing insomnia. 

Worsens Sleep Apnea

Sleep apnea is a common sleep disorder in which breathing repeatedly stops and starts during sleep when the airways are partially or fully blocked. Alcohol relaxes upper airway muscles, increasing the likelihood of the airways collapsing and more sleep apnea episodes, leading to more sleep disruptions. 

Worsens Snoring

Alcohol slows your breathing and causes you to take more shallow breaths. It also relaxes the airway muscles, narrowing the airways. The tissues vibrate and produce snoring sounds as you breathe. Snoring may wake you or your partner up, leading to more fragmented sleep.

Triggers Sleep Talking and Sleepwalking

Alcohol can trigger parasomnias, involuntary sleep behaviors that contribute to poor sleep quality, such as sleep talking and sleepwalking. By interfering with your body's normal circadian rhythm and sleep cycles, alcohol increases the likelihood of disruptive sleep behaviors that pose a safety risk. 

Adverse Effects of Disrupted Sleep

Sleep disruptions from alcohol consumption can harm your overall health and well-being. 

Stress Hormones

Disrupted sleep can increase the production of stress hormones like cortisol. People who get good-quality sleep typically have higher cortisol levels in the morning that decline throughout the day, reaching their lowest level at bedtime. Research shows that people with consistently poor sleep quality maintain high cortisol levels throughout the day, including at bedtime.

Elevated cortisol levels can contribute to feelings of irritability, anxiety, and overall stress and increase the risk of long-term health problems. 

Heart Rate

Fragmented sleep can negatively affect your heart health. Research shows that poor sleep quality and disrupted sleep raise heart rate, heart rate variability, and blood pressure while you sleep, which can stress the heart and increase the risk of cardiovascular diseases.

Learning and Memory

Sleep is essential for consolidating information learned throughout the day and performing daily tasks. Sleep disruptions and lack of sleep can impair the brain's ability to process and store new information, leading to a decline in cognitive functioning and problems with focus, memory, attention, alertness, decision-making, and judgment.

Hot Flashes

Poor sleep quality impairs your body's ability to regulate body temperature. For menopausal women, in particular, disrupted sleep can trigger or worsen hot flashes. Sleep disturbances disrupt hormonal balance, which affects body temperature regulation. 

How Much Alcohol Does It Take to Affect Sleep?

Even a small amount of alcohol can disrupt your sleep quality. Experts recommend avoiding alcohol at least four hours before bedtime to prevent adverse effects on sleep. 

Moderate drinking, defined as one drink for women and two drinks for men per day, can cause sleep disruptions, including a shorter duration of sleep, frequent night awakenings, and disrupted sleep stages. Drinking more alcohol or stronger alcoholic beverages will have a more significant impact on your sleep, with a sharper reduction in REM and deep sleep, leaving you feeling tired and groggy the following day.

Why You May Feel Tired the Day After Drinking Alcohol

A feeling of fatigue after a night of drinking isn't just from sleep interruptions. Alcohol has other effects on your body that contribute to feeling tired and sluggish the following day. Alcohol is a diuretic, meaning it increases urine production and fluid loss from the body more quickly than you can replace it. Dehydration zaps your energy levels, making you feel tired and less alert than usual. 

When your body is dehydrated, blood volume and blood pressure decrease, making it harder for your heart to pump blood efficiently. Dehydration also decreases oxygen and nutrient delivery to your body's organs and contributes to fatigue. 

Alcohol also interferes with your body's ability to absorb essential vitamins and minerals from food, like folate or folic acid (vitamin B9), iron, and magnesium, which fuel your body's tissues and functions. Nutrient deficiencies can further contribute to low energy levels.

Tips for Managing Sleepiness After Drinking

While it's best to avoid alcohol altogether for a truly restful night's sleep, there are some strategies to minimize sleepiness after consuming alcohol, such as:

• Pace yourself with water: Alternate alcoholic beverages with glasses of water throughout the evening to help counteract the dehydrating effects of alcohol. 
• Hydrate before bed: Before falling asleep, drink a glass of water to help replenish your body's lost fluids.
• Limit caffeine and sugary drinks: Avoid caffeine and sugary drinks after consuming alcohol. While they may initially provide a pick-me-up, they can disrupt your sleep.
• Eat before drinking: Opt for a healthy, nutrient-dense meal before drinking, which can help slow the absorption of alcohol and prevent intoxication.
• Drink earlier in the evening: Avoid drinking alcohol at least four hours before bedtime to give your body time to metabolize the alcohol and reduce the impact on your sleep quality.  
• Prioritize sleep hygiene: Create a dark, cool environment and stick to a bedtime routine that helps you unwind and promotes sleep before bedtime. Sleep hygiene habits may include avoiding screens, gentle stretches, or breathing exercises before you sleep. 

Summary

While alcohol may initially make you feel drowsy, it can interfere with your sleep cycle, cause frequent night awakenings, and lead to poor sleep quality. Chronic or heavy alcohol consumption can worsen these effects and contribute to long-term health problems.

If you drink, practice moderation and prioritize your health with strategies like staying hydrated and maintaining good sleep hygiene to minimize the negative effects on your sleep. Avoiding alcohol altogether is recommended for a truly restful and restorative night's sleep. 

Read the original article on Verywell Health.

2024-06-18T16:44:18Z