Alcohol is a depressant that affects the central nervous system and slows down brain activity. Although it can induce feelings of relaxation and sleepiness, consuming alcohol, especially in excess, can lead to poor sleep quality and duration. Individuals with alcohol use disorders frequently experience symptoms of insomnia. Research has shown that alcohol use can worsen the symptoms of sleep apnea.
Drinking alcohol in moderation is generally considered safe, but every individual reacts differently to alcohol. As a result, alcohol’s impact on sleep largely depends on the individual.
One 2018 study compared sleep quality among subjects who consumed various amounts of alcohol:
Low amounts of alcohol: Having fewer than two servings of alcohol per day for men or one serving per day for women decreased sleep quality by 9.3%.
Moderate amounts of alcohol: Having two servings of alcohol per day for men or one serving per day for women decreased sleep quality by 24%.
High amounts of alcohol: Having more than two servings of alcohol per day for men or one serving per day for women decreased sleep quality by 39.2%.
When we consume alcohol, it enters our bloodstream through the stomach and small intestine. The liver's enzymes eventually break down the alcohol, but this process is slow. As a result, any excess alcohol remains in the body. The effects of alcohol depend on several factors, including the amount consumed, how quickly it was consumed, and the person's age and body composition.
To understand how alcohol impacts sleep, it is important to understand the different stages of the human sleep cycle. A regular sleep cycle consists of four different stages. The fourth stage, REM sleep, begins about 90 minutes after the individual initially falls asleep. Eye movements will restart, and the sleeper's breathing rate and heartbeat will quicken. Dreaming primarily takes place during REM sleep. This stage is also thought to play a role in memory consolidation.
Drinking alcohol before going to bed can lead to a reduction of REM sleep during the first two sleep cycles. As alcohol acts as a sedative, it can shorten the time it takes to fall asleep, and some people may quickly enter deep sleep. However, as the night goes on, this can create an imbalance between slow-wave sleep and REM sleep, resulting in less of the latter and more of the former. This imbalance can reduce overall sleep quality, leading to shorter sleep duration and more disruptions during the night.
Alcohol and Insomnia
Insomnia is a common sleep disorder characterised by difficulty falling or staying asleep, even when there is an opportunity to sleep. This condition leads to excessive daytime sleepiness and other negative effects.
Alcohol consumption can reduce REM sleep and cause sleep disruptions. As a result, those who drink before going to bed often suffer from insomnia symptoms and feel excessively sleepy the following day. This can lead to a vicious cycle where they self-medicate with alcohol to fall asleep, use caffeine and other stimulants during the day to stay alert, and then rely on alcohol to offset the effects of these stimulants.
Binge Drinking
Binge drinking refers to consuming an excessive amount of alcohol in a short period, leading to a blood alcohol level of 0.08% or higher. This habit can have a negative impact on the quality of sleep. Research has shown that individuals who frequently engage in binge drinking are more likely to experience difficulty falling and staying asleep. This trend is observed among both men and women, as well as different age groups ranging from adolescents and young adults to middle-aged and older adults.
Studies have shown that there is a correlation between prolonged alcohol abuse and chronic sleep issues. As people develop a tolerance for alcohol, they may consume more before going to bed to feel drowsy. Individuals with alcohol use disorders commonly experience symptoms of insomnia.
Alcohol and Sleep Apnea
Sleep apnea is a condition that results in irregular breathing patterns and temporary breathing pauses during sleep. These breathing interruptions can lead to sleep disturbances and reduced sleep quality. Obstructive sleep apnea (OSA) emerges from physical blockages in the throat's back, whereas central sleep apnea (CSA) results from the brain's inability to signal the breathing muscles properly.
Sleep apnea is a disorder where breathing can stop during sleep, causing the sleeper to make choking noises. Loud and disruptive snoring is also a common symptom of sleep apnea. Studies show that alcohol can worsen sleep apnea symptoms by relaxing the throat muscles, causing more resistance during breathing. This can result in more disruptive breathing episodes and heavier snoring. Even those who have not been diagnosed with sleep apnea can experience symptoms of OSA and heavy snoring after consuming just one serving of alcohol before bedtime.
The relationship between alcohol consumption and sleep apnea has been extensively studied, and it is generally agreed that drinking alcohol increases the risk of sleep apnea by 25%.
Does alcohol help me sleep?
Alcohol can help you fall asleep faster due to its sedative properties. But if you drink before bed, you may face disturbances in your sleep cycle later on as your liver enzymes break down the alcohol. This can cause excessive sleepiness and other problems during the day. Additionally, relying on alcohol to fall asleep can lead to tolerance, which means you may need to consume more alcohol each night to achieve the same sedative effects.
Will a Small Amount of Alcohol Affect My Sleep?
Excessive drinking can have a negative impact on sleep compared to light or moderate alcohol consumption. Studies indicate that individuals who consume large amounts of alcohol before bedtime may fall asleep quickly but are more likely to experience sleep disruptions and a decrease in sleep quality. However, the effects of alcohol can vary from person to person, and even small amounts of alcohol can lead to a reduction in sleep quality for some individuals.
When Should I Stop Drinking Prior To Bed To Minimise Sleep Disruption?
To minimise the negative impact of alcohol on your sleep, it is recommended that you allow your body enough time to process alcohol before going to bed. To avoid disturbances in your sleep, it's advised that you refrain from consuming alcohol at least four hours before your bedtime.
