New York Times: Alcohol disrupts what’s known as your sleep architecture, the normal phases of deeper and lighter sleep we go through every night.
A night of drinking can “fragment,” or interrupt, these patterns, experts say, and you may wake up several times as you ricochet through the usual stages of sleep.
“You pay for it in the second half of the night,” said Dr. Jennifer Martin, a psychologist and professor of medicine at the University of California, Los Angeles. Alcohol is “initially sedating, but as it’s metabolized, it’s very activating.”
Here’s how it breaks down. In the first half of the night, when fairly high levels of alcohol are still coursing through your bloodstream, you’ll probably sleep deeply and dreamlessly. One reason: In the brain, alcohol acts on gamma-aminobutyric acid, or GABA, a neurotransmitter that inhibits impulses between nerve cells and has a calming effect. Alcohol can also suppress rapid eye movement, or REM sleep, which is when most dreaming occurs.
A glass of wine serves to help you wind down after a long day at work, but it’s not doing you any favors in the bedroom. When you stop drinking alcohol, not only does your mood improve and your skin clear up, but your sleep quality may also get better. Although many people rely on a glass of wine to relax and fall asleep, even just one drink greatly diminishes the quality of that sleep, says neuroscientist Kristen Willeumier, PhD.
Even a few ounces of alcohol changes the basic structure of normal sleep. Having a drink to help you fall asleep is an ineffective sleep strategy that can lead to a multitude of sleep disturbances, including insomnia, excessive daytime sleepiness, and alterations in sleep architecture, says Dr. Willeumier. “The most prevalent changes in sleep architecture occur early in the evening when blood alcohol levels are high,” she says. “While alcohol is initially sedating, once it is metabolized it can lead to disrupted, poor quality of sleep later in the night.”
If you really want to maintain healthy sleep, Dr. Willeumier says to limit your alcohol intake to one drink per week. “Alcohol should not be consumed on a regular basis if your intention is to live a brain-healthy lifestyle,” she says. But if that’s not something that interests you, you can undo the impact of alcohol on your sleep when you take a break.
“The good news is that your sleep architecture can be fully restored after a period of abstinence,” she says. “Given that sleep architecture and efficiency decline with age, it is important to keep in mind that alcohol will further exacerbate these issues.”
“Given that alcohol is a central nervous system depressant and has a half-life of anywhere from six hours or longer depending on type of alcohol and volume consumed, you want to drink it at least six hours prior to bed if you do not want it to interfere with your sleep cycles,” she says.