Alcohol can sometimes leave you feeling drowsy. But while alcohol, a depressant, can help you fall asleep faster, it also contributes to poor quality sleep later. Here’s what happens—when you go to sleep after drinking.
Sleep rhythms have a battle.
Drinking alcohol before bed is linked with more delta activity -slow-wave sleep patterns. That’s the kind of deep sleep that allows for memory formation and learning. At the same time, another type of brain pattern—alpha activity—is also turned on. Alpha activity doesn’t usually happen during sleep, but rather when you’re resting quietly. Together the alpha and delta activity in the brain after drinking may inhibit restorative sleep.
It can interrupt your circadian rhythm.
It's common to wake up in the middle of the night after falling asleep quickly after drinking. One explanation is that alcohol may affect the normal production of chemicals in the body that trigger sleepiness when you’ve been awake for a long time, and subside once you’ve had enough sleep. After drinking, production of adenosine (a sleep-inducing chemical in the brain) is increased, allowing for a fast onset of sleep. But it subsides as quickly as it came, making you more likely to wake up before you’re truly rested.
It blocks REM sleep.
Another reason people get lower-quality sleep following alcohol is that it blocks REM sleep, which is often considered the most restorative type of sleep. With less REM sleep, you’re likely to wake up feeling groggy and unfocused.
Alcohol can aggravate breathing problems.
Alcohol causes your whole body to relax, including the muscles of your throat. And that makes you more prone to snoring and sleep apnea.
Drinking leads to extra bathroom trips.
Typically, your body knows that nighttime is time for sleep, not the time for trips to the bathroom. That means that your body has learned to put your bladder into hibernation for the night. But alcohol, a diuretic, can make you need to go more, interrupting your normal sleep pattern.