Here’s What Happens to Your Sleep When You Go to Bed After a Night of Drinking

We’ve probably all been there: indulging in just one more glass of wine or cocktail than we should. And while alcohol may help you fall asleep quickly, the next morning the consequences set in. It’s common to feel groggy, slow moving, and irritable — and quite likely, have a pounding headache, unsettled tummy, and more unpleasant symptoms.

We spoke to sleep doctors to determine exactly what happens to your body when you go to bed after a night of drinking — and why your sleep is so particularly dreadful.

The good news? Alcohol’s soporific effects will send you off to dreamland fast. But it won’t be the deep, restorative rest your body craves.

“If you drank more than your typical amount, it’s probably not going to be a great night’s sleep,” says Jocelyn Cheng, MD, a neurologist specializing in sleep medicine and epilepsy at NYU Langone Health.

Here’s what happens, says Cheng: At first, you’ll fall into a deep, hard sleep. But several hours later, you’ll wake up prematurely and find it difficult to sleep again. Blame the booze, which messes with your sleep stages. “With a normal cycle of sleep, you go through stages of sleep like slow wave then REM, or rapid eye movement sleep, and then as the night goes on, there’s increasing amounts of REM sleep — when you have alcohol in substantial amounts you disrupt that pattern,” Cheng says.

That adds up to fragmented sleep in the pre-dawn hours, and feeling unrested in the morning.

In the hours after you stop drinking, your liver will metabolize the alcohol in your beverages, says Nate Watson, MD, MS, SleepScore Labs advisory board member. To do that, it uses two enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), Watson says. “These enzymes break apart the alcohol molecule allowing it to be eliminated from the body.”

Gone — but not forgotten, because alcohol’s effects linger on in the form of a hangover.

There’s no set timing for when a hangover sets in, says Sujay Kansagra, MD, Mattress Firm’s sleep health expert, since it depends on how much you drank and slept, among other factors. “Most will feel the effects upon awakening when the alcohol content of the blood has become minimal,” says Kansagra.

Dehydration is your biggest enemy — and the biggest force — behind a hangover. It’ll cause thirst, dry mouth, and dizziness, says Watson. An electrolyte imbalance may also occur, Watson says. Those two factors — dehydration and electrolyte imbalance — will contribute to that hungover feeling that kicks in several hours after your last drink, says Watson.

For better sleep, stop drinking sooner. And drink less, too. This is easier said than done, of course.

“In an ideal world, in order to protect our sleep, we’d have our last drink about three hours before going to sleep and have only one or two drinks per night,” says Lynelle Schneeberg, PsyD, Fellow, American Academy of Sleep Medicine.

If you ignore this excellent advice, hydration remains your best hope for avoiding the very worst hangover symptoms. “Drink copious amounts of water before going to bed following a night of drinking,” advises Watson. “This will resolve the dehydration and get your body back on track,” he says.

Keep hydrating once you wake up, too. A non-steroidal anti-inflammatory painkiller can help with your headache, says Watson. Mostly, though, you’ll have to wait out the symptoms. As Watson points out, “time is the ultimate healer of the hangover.”