Alcohol can make you feel sleepy because it’s a central nervous system depressant, meaning it slows down brain activity, which can lead to drowsiness.
Your central nervous system includes your brain and spinal cord. Alcohol is a central nervous system depressant, which means it slows down brain activity. It does this by affecting chemical messengers in your brain called neurotransmitters.
Alcohol has its most notable affects on two neurotransmitters:
- Gamma-aminobutyric acid (GABA): This is the main neurotransmitter that slows down nerve activity. Alcohol may make GABA work better, slowing down the brain even more.
- Glutamate: This chemical messenger helps with memory, mood, and thinking. By decreasing the action of glutamate, alcohol may make you feel more relaxed and less in control. This sedative effect may be why you feel drowsy after drinking alcohol.
Abstaining from alcohol may be the best way to avoid getting sleepy from alcohol and experiencing alcohol-related sleep disruptions, which can happen with even small amounts of alcohol. If you choose to drink, here are some strategies to minimize sleepiness and the impact alcohol may have on your sleep patterns:
- Know your tolerance, and set a drinking limit beforehand.
- Choose beverages with lower alcohol content.
- Drink water alongside alcohol.
- Eat a nourishing meal before drinking to slow down alcohol’s effects.
- Drink earlier in the evening to give your body more time to metabolize the alcohol before bedtime.
- Practice good sleep hygiene, such as by keeping your bedroom cool, dark, and comfortable for sleep.
- Consult a doctor if alcohol significantly affects your sleep or daily life.
Alcohol’s sedating effects may help you get tired and doze off initially, but that doesn’t make alcohol a good sleep aid.
In fact, alcohol can have significant negative effects on your sleep quality, which can affect your overall health in addition to how rested you feel.
Here’s a look at the ways alcohol can lead to poor sleep quality:
Disrupts Deep Sleep
Initially, alcohol’s sedating effects may help increase slow-wave sleep in the first half of the night, considered the deepest sleep stage. While alcohol may help you drift off quickly and deeply, it also disrupts your sleep later in the night, leading to more awakenings and increased light sleep. The disruption of your sleep stages can occur even with small amounts of alcohol.
Chronic sleep disturbances and a reduction in slow-wave or deep sleep are particularly prominent in people who binge drink or drink heavily, and these issues can persist into periods where you’re not drinking.
Suppresses REM Sleep
During rapid eye movement (REM) sleep, your brain is very active and your eyes move rapidly, but your arms and legs are temporarily unable to move. REM is the stage of sleep where most dreams occur, and it’s essential for memory and learning. Alcohol suppresses REM sleep, leading to a longer time before entering REM and reduced REM sleep during the first half of the night, or even throughout the entire night.
Increases Daytime Sleepiness
Sleep disruptions related to drinking alcohol can make it more challenging to stay awake and alert the next day. Heavy drinking, especially when paired with insufficient sleep, increases the likelihood of this daytime sleepiness. In people with alcohol use disorder, excessive daytime sleepiness may happen during periods of both drinking and abstinence.
Contributes to Insomnia
Alcohol use (as well as long naps, which people may take if they experience daytime sleepiness from drinking the night before) can contribute to insomnia. Insomnia is a common sleep disorder where a person has trouble falling asleep, staying asleep, or getting good-quality sleep.
Some people with insomnia may turn to alcohol as a quick fix to bring on sleep. But this can create a harmful cycle, where drinking to sleep disrupts your rest, resulting in daytime sleepiness and, ultimately, insomnia again.
May Cause Other Sleep Issues
Alcohol can disrupt sleep even with occasional drinking, but for people who drink heavily or have alcohol use disorder, the sleep problems can be more severe. Drinking more heavily may also lead to conditions and symptoms such as:
- Obstructive sleep apnea (OSA): Alcohol interferes with normal breathing during sleep, leading to OSA. Sleep apnea can cause or worsen snoring, lead to sleep-disordered breathing, and disrupt your overall rest.
- Delayed sleep phase disorder: This disrupts the body’s internal clock, or circadian rhythm, and leads to falling asleep much later than typical bedtimes.
- Periodic limb movement disorder: This is characterized by repetitive arm or leg movements during sleep that further disturb your restful sleep.
- Night terrors: These sudden episodes of intense fear during sleep are often accompanied by screaming, sweating, and fast heart rate.
Beyond sleep problems, drinking alcohol can harm your health in other significant ways, especially if you drink heavily. These include:
- Mood and cognitive changes: Alcohol can change how your brain works, affecting your mood and behavior and making it harder to think clearly.
- Heart health concerns: Heavy drinking can cause heart conditions such as high blood pressure, irregular heartbeat, and stroke.
- Liver damage: Drinking can damage your liver, an organ that removes toxins from your body.
- Pancreatitis: Drinking over time can lead to inflammation of the pancreas.
- Cancers: Alcohol is considered a carcinogen, meaning it can increase the risk of certain types of cancer, including breast cancer, colorectal cancer, esophageal cancer, and head and neck cancer.
You might feel sleepy when you drink alcohol because alcohol slows down brain activity. While alcohol may help you feel tired and fall asleep faster, it often disrupts your sleep quality, too, leading to more awakenings and less restorative sleep. By being mindful of your drinking habits, such as by pacing yourself and drinking enough water, you can help minimize these and other negative effects.
