Whether you sip a few Old Fashioneds as you watch “The Americans” or slam a few beers at happy hour, alcohol seems to help you slide quickly into sleep, doesn’t it? That’s because alcohol is a two-headed beast: It initially acts as a stimulant, sending those feel-good chemicals to the brain that make you more likely to belt out some “Man in the Mirror” at office karaoke. Once it starts metabolizimg in your system, however, its sedative effects kick in.
But while alcohol makes it easier to fall asleep, it doesn't help you stay asleep. Instead, it screws with your sleep cycle and jolts you awake at ungodly hours. In fact, much of the misery of a hangover comes from simple sleep deprivation. Here are six things that alcohol does to your body when you throw back more than a couple before bed.
1. You'll Fall Asleep Faster
Alcohol brings on sleep about 15 minutes earlier than normal and initially causes increased amounts of dreamless deep sleep. So, the first few hours of drunk snoozing appear to be quite heavy. According to Timothy Roehrs and Thomas Roth of the Sleep Disorders and Research Center, alcohol inhibits the neurotransmitters GABA and glutamate, dramatically decreasing brain activity, which induces drowsiness. However, alcohol also keeps the sympathetic nervous system from shutting down, so your body stays partially awake. Your heart beats about 20 percent faster than it would during a sober slumber.
2. Your Body Temperature Will Drop
Although it can feel warming, alcohol actually lowers body temperature. Body temperature normally takes a dip after you fall asleep, but the slightly larger drop brought on by booze disrupts the circadian hormone schedule. Good sleep depends on the production of hormones like HGH and melatonin, and a drunk pituitary gland doles them out in smaller amounts at the wrong times.
3. You'll Shake the Walls
Since it’s a muscle relaxant, alcohol worsens snoring and sleep apnea by loosening the muscles that keep your airway open. Not enough oxygen is getting to the brain, so it wakes up the body for a few seconds at a time to breathe, leading to low-quality, fragmented sleep. And, as many studies, including this one published in The Journal Neurology, Neuroscience and Psychiatry found, alcohol can dramatically worsen breathing difficulties for those with sleep apnea.
4. You Experience the "Rebound Effect"
Alcohol suppresses REM sleep during the first half of the night. In the second half, however, the body overcompensates by getting more of that sweet REM than usual. Sleep scientists call this the “rebound effect.” And while the total amount of REM ends up being the same as during sober sleep, it comes at the wrong time. REM sleep is relatively light. During the second half of drunk sleep, it joins forces with an increasingly alert nervous system to make it much easier to toss, turn, and wake up without knowing it. Case and point: According to a 2014 study, micro-sleep disruptions are 17 percent more common during drunk sleep.
5. You'll Get Up Early
Things don’t get much better after your liver has metabolized all the alcohol you drank. Your sympathetic nervous system never fully shuts off, and without the depressant effect of alcohol, it’s highly sensitive to stimuli. That means light and sounds you'd normally sleep through can now wake you up. And once you do wake up, the nervous system stays alert, making it difficult to fall back aslep.
6. You'll drag the next day
And not just in the immediate aftermath. In 1986, researchers got Navy pilots drunk and then tested them on a flight simulator 14 hours later, when they were completely sober. Compared to a teetotaler control group, the hungover pilots performed worse in every measure. Later studies established a link between poor hangover performance and alcohol-induced sleep disruptions.
So, how can you sleep better after a bender?
First, you'll want to stop drinking early...or stay up late. If you’re drunk, give your body time to metabolize as much alcohol as possible before you turn in. Depending on how much you’ve had, this could take around four hours, but you’ll sleep much better if you don’t pass out in peak party mode. And second, black out your room. Since you'll be sleeping very lightly during the rebound period, heavy curtains could give you some extra shuteye in the morning. Ear plugs could also be a big help. Regardless, the only way to get a good night's sleep is to have no more than one drink before you lie down for the night.