Alcohol and Insomnia: How Alcohol Affects Sleep
What is Insomnia?
When a person’s sleep is poor, they are at an increased risk for numerous health problems including diabetes, heart disease, depression, and obesity.1 Some people choose to unwind before bed with alcohol, which can act as a sedative that slows down brain activity.2 However, the research suggests that alcohol consumption generally has a negative impact on sleep quality. In fact, between 35% and 70% of individuals who use alcohol have insomnia.3 It may seem surprising, considering that alcohol is a depressant, yet alcohol is known to interfere with fundamental aspects of sleep quality.
Generally speaking, insomnia is defined as either a problem falling asleep, staying asleep, or waking up early and being unable to get back to sleep. The loss of sleep is enough to cause problems in day-to-day life and is occurring at least 3 nights per week for over 3 months.4
Insomnia is a common problem and the most common of all sleep disorders, with an estimated 33% of American adults reporting insomnia symptoms.4 Estimates suggest that almost 10% of people in the United States struggle with short-term insomnia. And of those, around 20% develop chronic insomnia, which can last for years.5
Not sleeping enough carries significant consequences, risks, and can be potentially dangerous. Decreased attention and concentration due to a lack of sleep is common, and persistent insomnia is associated with an increased risk of depression, hypertension, and heart attacks.4 Those with insomnia may miss work, have reduced productivity, and an overall reduced quality of life.4
If a person is tired due to insomnia, they are also at an increased risk for accidents. One study found that people with insomnia had more than a 20% risk of an accident in their home and over a 10% risk of a work-related accident. Additionally, 9% of individuals in the study fell asleep while driving, and more than 4% had a car accident related to their insomnia.5
As such, people with insomnia often try to self-treat the condition. An estimated 20% to 30% of people report drinking to manage insomnia.7 While alcohol can initially cause sedation, over time, alcohol causes major disruptions in the quality of sleep.
How Does Alcohol Affect Your Sleep?
Initially, a little alcohol before bed might seem helpful for insomnia. However, people can rapidly develop to the sedating effects of alcohol. A small study shows quite explicitly how quickly alcohol becomes ineffective when used repeatedly for sleep. In volunteers struggling with insomnia without a history of alcohol use, alcohol or a placebo were given nightly before bed. Initially, smaller amounts of alcohol did increase total sleep time and deep sleep. However, these effects were quickly lost within a week. As the study continued, subjects who had been given alcohol before bed were inclined to increase alcohol consumption, up to almost the equivalent of 3 beers a night. The study clearly demonstrates how quickly tolerance develops for alcohol, which puts a person at risk for developing alcohol use disorders.7
With higher doses, especially over long-term consumption, alcohol may have even worse effects on sleep. Higher doses of alcohol have been shown to disrupt sleep, particularly during the second half of the night.8
Studies also show that alcohol may exacerbate sleep-disordered breathing such as snoring and even obstructive sleep apnea. Heavy drinkers appear to be at increased risk of exacerbating sleep apnea, and this combination can increase a person’s risk of heart attack, stroke, and sudden death.9
Alcohol and Sleep Apnea
Research suggests that there may be a link between higher levels of alcohol consumption and an increased risk of obstructive sleep apnea, a potentially serious sleep disorder in which breathing repeatedly stops and starts.10
There are actually two different types of sleep apnea. Central sleep apnea isn’t as common as obstructive sleep apnea. It occurs because the brain doesn’t send the proper signals to the muscles that control breathing. The majority of sleep apneas are obstructive, which entails a collapse of the airway that blocks the flow of air into the lungs.11
Obstructive sleep apnea affects an estimated 15% of men and 5% of women—all of whom have a body mass index (BMI) greater than 28.10 While it’s well documented that obstructive sleep apnea is more common in older adults; current smokers; and individuals with coronary artery disease, hypertension, and diabetes, there is now a growing body of evidence suggesting that heavy alcohol use worsens obstructive sleep apnea symptoms.10,12
A meta analysis of 21 studies found that relative to people who did not consume any alcohol, those who consumed alcohol had 25% higher risk of having obstructive sleep apnea.10 The reasons for this are complex and multifaceted, and the authors acknowledge that some of the increased risk may be indirect, that is, the effects of alcohol on important contributors to obstructive sleep apnea, like a higher BMI.10
Can Alcohol Cause Insomnia?
As indicated, alcohol can indeed affect sleep. Research suggests that alcohol’s negative impact on sleep varies and is dose related. Indeed, a growing number of studies demonstrate an association between alcohol dependence—wherein the body becomes so used to having alcohol present that if an individual suddenly stops drinking, withdrawal symptoms surface—and sleep-related disorders like insomnia. The prevalence of insomnia for those struggling with alcohol dependence is estimated to be between 36% and 91%, which is well above average.8 Research has also associated binge drinking with disrupted sleep. Specific brain cells in the forebrain promote a state of wakefulness. Alcohol appears to inhibit neurotransmitters that activate these brain cells. This can disturb the whole sleep-wake cycle, disrupting sleep and potentially predisposing a person to insomnia.13
Alcohol’s Effects on REM Sleep
Sleep has two basic types: rapid eye movement (REM) sleep and non-REM sleep.14 Non-REM sleep has three different stages—the changeover from wakefulness to sleep, light sleep, and deep sleep. REM sleep first occurs about 90 minutes after falling asleep. During the night, you cycle through all the stages of non-REM and REM sleep several times with longer, deeper, periods of REM sleep occurring toward morning.14 Alcohol consumption has been shown to potentially disrupt virtually all stages of non-REM sleep and REM sleep, too.3
Although the research is a bit unclear and the results mixed, use of alcohol appears to decrease REM sleep overall. In general, research shows reduced quality of sleep with long-term alcohol use. These sleep quality issues can continue for months or years upon discontinuation of alcohol use but may improve over time with abstinence.3
Why Does Alcohol Make Me Sleepy?
As a central nervous system (CNS) depressant, alcohol has sedating effects. It can make people feel sleepy and also plays a role in promoting the sleep-wake cycle and rapid sleep onset. This is due to the complex and far-reaching effects alcohol has related to neurotransmitters involved in controlling sleep.15 And while this may seem like a reason to use alcohol to manage insomnia, with continued use, you quickly develop a tolerance to alcohol’s effects on sedation and sleep.7
How Does Alcohol Withdrawal Affect Sleep?
For people struggling with an alcohol use disorder, insomnia and disturbed sleep are a common symptom of both acute alcohol withdrawal (1 to 2 weeks) and continues throughout early recovery (2 to 8 weeks). Insomnia symptoms are often variable and sometimes improve quickly following detox, but can persist throughout early recovery Estimates suggest that between 36% and 91% of people experiencing withdrawal from alcohol have insomnia.16 During withdrawal and recovery, it is harder to fall asleep, sleep is typically fragmented, and the percentage of REM sleep is lower as is the duration of REM sleep. Problems with sleep can continue for months or longer for some patients as they enter the sustained recovery phase of alcohol use disorder.15