Is a nightcap part of your prep-for-bed ritual? That drink could ruin the quality of your sleep.
Up to 70% of alcohol users have symptoms consistent with clinical insomnia.[1] The more they drink, the higher the risk. For men, Heavy is associated with waking multiple times in the night.[2] Ironically, people with a drinking habit may reach for alcohol when they can't sleep, perpetuating a vicious cycle.
Stages of Sleep: Alcohol's Impact
Adults ideally need between 7 and 9 hours of sleep each night.[3] While you're resting in bed, your brain and body move through a series of stages. Alcohol impacts all of them.
Stage 1: Falling Asleep (Sleep Latency)
Alcohol is a sedative drug. It slows down your breathing rate, heartbeat, and brain waves. You feel fuzzy, relaxed, and ready to rest.
People who drink report that they can fall asleep faster with alcohol in their bodies.[4] This is called sleep latency. Overall, alcohol does shorten sleep latency, meaning people do tend to fall asleep faster. But does this mean they actually get more sleep, or feel more rested the next day? Not necessarily.
Stage 2: Non-REM Sleep
As you drop deeper into slumber, your heartbeat and muscle activity slow. Your body temperature drops, and your movement stills. While in these sleep stages, your tissues knit together, your immune system recharges, and your memories solidify.
Non-REM sleep is often called deep sleep. Your brain and body are doing important work, and it's critical for you to stay asleep.
Researchers say alcohol alters the quality of your non-REM sleep. Parts of your brain are aroused, which means you're easier to wake up.[5]
Stage 3: REM Sleep
Your heart rate increases, your brain awakens, and your eyes move from side to side. Your dreams begin, and your muscles may twitch and jerk in response.
Alcohol reduces your time in REM sleep, especially in the first part of the night.[6] If you manage to stay asleep and in bed, you can catch up on REM sleep later in the night. But if you're awakened and can't fall asleep again, you'll lose the opportunity.
REM sleep is critical for these things:
- Memory
- Processing emotions
- Brain cell restoration
Missing REM sleep, especially over several nights, can leave you feeling foggy, confused, and irritable.
The Biology Behind Alcohol and Sleep
We don’t know exactly how alcohol affects sleep. What we do know is that our brains use gamma-aminobutyric acid (GABA) to slow activity and help us feel relaxed. Alcohol mimics GABA, which someone allows someone to fall asleep more quickly.[7] However, within a few hours of sleep, our bodies metabolize alcohol's GABA-like molecules. The byproduct is glutamate, which is actually an excitatory molecule. This may stimulate your brain and prevent the natural REM sleep that we really need to achieve restful, restorative sleep.
Risks of Alcohol and Sleep
Alcohol-influenced sleep isn't restful. You may feel sleepy when you crawl into bed, but within a few hours, you may actually wake up more frequently and, even if you are able to maintain sleep, will not necessarily gain truly restorative sleep.
With heavy drinking, there are also risks of over-sedation, decreased respiratory drive, choking, aspiration and even death.[8]
Alcohol can exacerbate these other sleep related conditions:
Insomnia
People with alcohol use disorders often drink to improve their sleep.[9] They may fall asleep faster after a few drinks, but they may not stay asleep or experience restful sleep.
Sleep Apnea
Open nasal passages and throat tissues make smooth breathing possible. But people with sleep apnea experience repeated airway blockages.
They may snore, but they may also stop breathing altogether multiple times each night. Body tissues are starved for oxygen during these episodes.
Drinking a large amount of alcohol raises your risk of sleep apnea by 25%.[10] If you already have apnea, alcohol will make this condition worse.
Increased Wakefulness
Many people awake in the night and struggle to fall asleep again. Stress, a noisy bedmate, or a bothersome pet could all keep you awake at night. Alcohol can do the same thing.
Your body relies on melatonin to fall and stay asleep. Researchers say alcohol reduces melatonin production by up to 19%.[11] Even a small amount of alcohol can ruin a good night's sleep.
What Should You Do Next?
If you find yourself frequently relying on alcohol to help you sleep, you may have a sleep disorder and/or an alcohol use disorder. It might be a sign that you could benefit from some professional help. Talk to your doctor about other ways of obtaining healthy, natural sleep.
Alcohol & Sleep FAQs
How does alcohol affect your sleep?
Alcohol tends to decrease sleep latency (time to falling asleep) and therefore may help you fall asleep faster, but your overall sleep quality is usually worse. You may spend more time in deep sleep and less time in REM sleep too, leaving you feeling foggy and confused the next day.
How much alcohol can ruin your sleep?
Depending on your tolerance, even one drink drink can negatively impact your quality of sleepthos.[12] Unfortunately there is no guaranteed safe amount of alcohol to drink to preserve a good night's sleep.
Is it dangerous to sleep while drunk?
Falling asleep while severely intoxicated does increase the risk of choking, aspiration, and respiratory suppression which can lead to overdose and even death. If you are drinking to the point of “passing out”, it could be a sign of an alcohol use disorder, and you should seek help from a doctor or other mental health professional.
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