Why Alcohol Disrupts Your Sleep

A glass of wine may help you relax and nod off, but having it too close to bedtime can lead to poor sleep quality and a groggy, not to mention hangover-plagued, morning after.

When you’re wound up at the end of a long, stressful day, a nightcap may sound like the perfect way to relax before bed. But while a little alcohol may make you feel sleepy, it can set you up for a restless night. Can you unwind with a late-night drink without winding up fatigued in the morning? Probably not.

“Alcohol is a depressant, which can help somebody feel like it’s relaxing them and helping them to fall asleep,” said Charlene Gamaldo, MD, associate professor of neurology, pulmonary, and critical medicine and director of the Neuro-Sleep Division at Johns Hopkins Hospital. “But alcohol also is rapidly metabolized in your system and, when your body washes the alcohol out, it’s more likely to cause what we call a rebound alertness.”

Sleep investigators have found that this rebound alertness tends to strike in the second half of the night, which is when you would normally be in the period of rapid eye movement (REM) deep sleep. Missing out on REM sleep can worsen daytime sleepiness — that’s why you’re likely to feel that you’re dragging through the day after a night of drinking. Poor sleep quality can also cause problems with alertness the next day.

Sleep problems due to alcohol get worse over time. Between 10 and 15 percent of cases of chronic insomnia are related to substance abuse, including alcohol abuse.

“For folks who chronically use alcohol, particularly to aid with sleep, it can really mess up their natural cycle of getting to sleep and staying asleep,” explained Dr. Gamaldo. “They never get into deep REM sleep because they’re waking up when the alcohol wears off.”

When you overdo it on the alcohol and drink in excess, it may lead to a morning-after headache, nausea, and the overall miserable feeling of a hangover. But it doesn’t take a binge to suffer these effects. If you have a nightly drink, you’re likely to wake earlier and earlier. “The more and more you do that, your body gets more and more acclimated to metabolizing the alcohol even faster. It’s a vicious cycle — you feel like you need it to get to sleep because you’re waking up so much in the middle of the night, but the behavior is complicating the issue even more,” added Gamaldo.

Why Alcohol Is a Sleep Disruptor

Drinking too much wakes you up for two main reasons, explained Gamaldo. First, alcohol is a diuretic, so your body works hard to metabolize it and creates large volumes of urine to help you get the alcohol out of your body. So, you’ll likely need to get up in the middle of the night to use the bathroom. “That sense of a hangover is actually from intense dehydration from your body getting rid of all that alcohol,” said Gamaldo.

Second, you’ll have the rebound waking as your body bounces back from the depressant effects of the alcohol. Also, too much alcohol can weaken airway muscles, triggering (or worsening) sleep disturbances like sleep apnea or heavy snoring.

When a hangover wakes you up early, it’s partly because your body is craving fluids to replace what was lost through the increased urine output. Have plenty of water or electrolyte replacement drinks.

Skip the Booze to Sleep Soundly

If you’re looking for a solid night of sleep, work on developing good sleep habits instead of reaching for a drink. A Japanese study looked at the impact of cutting out alcohol before bed. Within one month, those who stopped having a nightcap saw the biggest improvements in their sleep; participants felt less sleepy and reported an improvement in the quality of their sleep.

Other smart steps to better sleep include:

  • Exercising every day
  • Spending time in the sunlight each day
  • Making sure your bedroom is comfortable, dark, and quiet
  • Avoiding eating and drinking too close to bedtime, and avoiding caffeine in particular
  • Creating a sleep/wake schedule
  • Developing a soothing pre-bedtime routine

In moderation, alcohol has some benefits, but use caution. “The take-home message is not to resort to alcohol as a go-to sleep aid. If you’re having trouble sleeping, wean off alcohol, especially if you’re having problems maintaining sleep,” said Gamaldo.

By Diana Rodriguez

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