“Everything around me is spinning. It feels like I haven’t slept in ages” is a common joke that most people make after having a night out where they drank to a point of blacking out.
Have you ever wondered why this happens? Why is it that once you wake up after a night of binge drinking with friends, you are uncomfortable, dizzy, and extremely irritable despite falling asleep rather quickly the past night?
That’s because alcohol can seriously affect your sleep and the typical “hangover” that most people experience following a drunken night out can affect the brain in so many different ways that one can’t imagine. And these effects can even occur following even a little bit of drinking.
In this article, we will discuss alcohol and its connection to your brain in terms of sleep.
Alcohol and Sleep
By nature, alcohol is a depressant of the nervous system which means that it reduces your brain activity. It also possesses sedative effects that can cause sleepiness and relaxation. (1) So why is it that you are not fresh at all after drinking too much?
That’s because alcohol, especially when taken in large amounts, decreases the quality as well as the duration of your sleep. Studies have even shown it to exacerbate the symptoms of many sleep-related problems, including sleep apnea and insomnia.
Consuming moderate amounts of alcohol is normally considered safe in most people, but the truth is, this potentially addictive beverage affects everyone differently. So the exact way in which alcohol can affect sleep also varies from one person to another.
How Alcohol Affects Sleep
As soon as you consume alcohol, it gets absorbed in the stomach and small intestine to enter the bloodstream. (2) Then, it starts traveling to the liver where it is acted upon by several metabolic enzymes. However, this process of breakdown is rather slow and until it occurs, there is a huge amount of alcohol still circulating in the blood, producing its effects.
As mentioned before, the exact way in which alcohol reacts with the body to produce effects varies on an individual basis. Some important factors that govern these effects include the person’s age, body type, sex, physique, the type of alcohol used, and how quickly it was consumed.
A vast amount of research has been carried out on the connection between alcohol and sleep during the past few decades, yet there is a lot to unravel and understand. (3) In general, scientists have found that users who consume alcohol in large amounts just before going to bed usually suffer from delayed onset of sleep. During the night, their liver keeps metabolizing the alcohol to reduce its level in the blood, and as this process is occurring, such individuals are also more prone to experience frequent sleep disruptions. Their overall quality of sleep is also greatly reduced.
Alcohol and the Normal Sleep Cycle
To better understand how alcohol affects sleep, you must first understand what a sleep cycle is along with its different stages. While you are sound asleep in your cozy bed, your brain is passing through different stages of sleep, each with its own characteristics and features.
A normal human sleep cycle is divided into four stages; three of them are the non-rapid eye moment stages or the NREM stages, while the remaining one is known as the rapid eye moment stage or the REM stage.
Let’s look at these stages individually.
Stage One (NREM)
This is the first stage of the sleep cycle and occurs as you are between the states of sleep and wakefulness. It is when your body slowly starts shutting down. The breathing pattern, heartbeat, and eye movements slowly start decreasing. Additionally, different muscles of the body start relaxing.
Within minutes, the brain activity also starts decreasing, and you are said to be in “light sleep.”
Stage Two (NREM)
This is the longest of all four stages of sleep and is characterized by further slowing down of the breathing and heart rate as you slowly enter into a deeper sleep. At this point, your body temperature also starts decreasing while your eyes remain still.
Stage Three (NREM)
Also known as slow-wave sleep, your body is experiencing the lowest levels of brain activity, heartbeat, and breathing rate in this particular stage. A complete cessation of eye movements occurs followed by relaxation of all the muscles.
Stage Four (REM)
The REM stage of the sleep cycle begins around 90 minutes after you fall asleep. During this phase, your eye movements which may have decreased previously restart and your heartbeat and breathing rate begin to increase.
REM sleep is particularly important since many significant processes are taking place during this stage. For example, you are more likely to dream in this particular stage. Additionally, most of the work needed for cementing the short-term memory to long-term memory is carried out in this particular stage. (4)
The four stages of sleep keep running in a cyclical pattern as you continue to sleep throughout the night. The duration of each of these cycles is around 90 to 120 minutes, which means that you are likely to go through at least three to five cycles for every 8-hour long sleep session.
The NREM slow-wave sleep usually dominates the first two cycles of your sleep with the REM stage only lasting for a maximum of 10 minutes. However, with time, the latter becomes more dominant and stretches itself up to 40 minutes or even longer, with a cessation of NREM stages.
So How Does Alcohol Disturb These Stages Of Sleep?
When you drink alcohol just before going to bed, it suppresses the already shrunken REM sleep during the first two sleep cycles. Because it possesses sedating properties, it often shortens the onset of sleep, making some go into a deep sleep rather quickly. However, during the late hours of the night, an imbalance might be caused between the REM sleep and the slow-wave sleep that decreases the overall quality of sleep. This imbalance can also shorten the duration of your sleep session and may force you to wake up several times in between.
Alcohol and Insomnia
Insomnia is one of the most common sleep disorders and is diagnosed when a person persistently faces difficulty in initiation, consolidation, and duration of their sleep. The victims of this condition constantly fail to sleep at night despite a strong desire, and consequently develop other simultaneous problems such as daytime sleepiness.
Because alcohol tends to directly target and reduce REM sleep and cause frequent sleep disruptions, people who consume this beverage before bedtime are more prone to experiencing the symptoms of insomnia. This is also the reason why they feel extremely tired and sleep the following day.
In the long run, this situation sets up a vicious cycle in which people start self-medicating themselves with alcohol just to go to sleep at night while relying on caffeine to keep awake during the day. (5)
You often come across a term called binge drinking which refers to consuming massive amounts of alcohol in a relatively shorter period in such a way that the blood concentration goes higher than 0.08%. Such practices can harm the quality of sleep to a great extent.
Recent studies have been conducted to study the effects of binge drinking, and have concluded that people who indulge in binge-drinking at least once a week are more likely to suffer from insomnia and other sleep-related difficulties. Similar effects have been seen in different age groups, including adolescents, young adults, middle-aged people, and older individuals. (6,7)
Studies have also found that long-term use of alcohol often leads to chronic sleep problems. This is because most individuals become tolerant to the effects of alcohol in a very short time and have to increase their dose to initiate sleep.
Alcohol and Sleep Apnea
Sleep apnea refers to abnormal breathing patterns during sleep that may sometimes even lead to a loss of breath temporarily. These frequent lapses in breathing can decrease the overall sleep quality as they disturb the normal sleep cycle multiple types throughout the night. During an apnea episode, choking noises are normally produced by the victim. Such people are also loud snorers in general.
But does alcohol play any role in causing sleep apnea? According to some studies, yes. In many instances, alcohol can relax the muscles of the throat, increasing the resistance during normal breathing and exacerbating the symptoms of apnea. Even in people with no history of this disease, alcohol can induce heavy snoring and apnea episodes.
In general, the risk of experiencing sleep apnea increases by 25% in people who consume alcohol. (8)
While drinking out with friends sounds appealing and may seem like something you would like to do often, it can potentially damage your brain, directly affecting sleep habits. In the long run, you may even find yourself caught up in a vicious cycle which is only going to worsen your sleep cycle and make you incapable of remembering a lot of things.
To avoid these effects, drinking in moderation is advised; however, remember that irrespective of the dose, alcohol can always damage your body and the effects can vary in different individuals.