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The Anatomy of a Hangover

Thursday, December 29, 2022 10:39 AM

By Isabelle Banin

From eggs Benedict to pickle juice and poutine, foods from around the world are celebrated as hangover cures. Let’s cut to the chase—there is no cure. However, understanding what’s going on inside your holy temple after an alcohol binge can hasten your recovery.

Hangovers are withdrawal effects that happen when our bodies process and filter out alcohol, said NorthShore Chief of Emergency Medicine Ernest Wang, MD. Since alcohol impacts such a broad range of bodily systems, and many of its effects depend on the person or what was in their drink, hangovers are far more complex than they may seem, he added.

Close-up shot of two unrecognizable hands holding a tequilla shot at a birthday celebration. They're ready for a toast.Dehydration

Alcohol makes you urinate a lot since it suppresses vasopressin, a hormone that regulates the balance of fluid in your body. Excessive sweating, vomiting and diarrhea can also be triggered by alcohol. This is the perfect recipe for dehydration, which can cause lightheadedness, fatigue, stomach cramps and headache. Dehydration can cause vertigo if one ear loses more water than the other, though hangover vertigo can be tied to alcohol disrupting the brain’s sensory processing.

If you are feeling severe symptoms of dehydration, such as intense thirst, delirium and rapid heartbeat, call 911 or head to an emergency room. Severe cases of dehydration are life threatening.

Bad Sleep

It’s not unusual to zonk out after a night of drinking—then wake up at 4 am feeling dead tired and sleeping fitfully the rest of the night. Though alcohol is a sedative, brain activity will increase after the alcohol leaves your body. Once you wake up (as a result of your overactive brain and/or the pressing need to use the bathroom), your normal sleep cycle may be disrupted for the rest of the night. On top of feeling dehydrated, a night of bad sleep will make you feel exhausted, cranky, irritated, and unfocused the next day.

Stomach Pain

Alcohol increases your body’s production of lactic acid, and pancreatic and intestinal secretions. The excess digestive fluid can irritate your stomach lining, which can cause nausea, vomiting and diarrhea. Losing fluid through vomiting and diarrhea will worsen your dehydration as well.

Mood Changes

While drunk, your brain adjusts to the mood boost that alcohol gives you. As the alcohol leaves your system, you may feel even sadder and more anxious than usual. Hangovers can also trigger anxiety or depression if you are predisposed to those conditions, and increase the amount of cortisol (stress hormone) in your body. Muscle aches, stomach pain and all other potential hangover symptoms will worsen your mood as well.

General Discomfort

Alcohol triggers our immune system and causes oxidative stress, which increases the amount of general inflammation in our bodies. Higher levels of inflammation have also been shown to increase hangover severity

Congeners, another naturally occurring chemical in alcoholic drinks, also increase hangover severity for some people. Red wine and dark spirits like bourbon have a higher level of congeners, while lighter spirits generally (but not always) have lower levels.


There are many reasons hangovers lead to headaches. Alcohol expands blood vessels, which contract after the alcohol leaves our system. Both the expansion and contraction of blood vessels cause headaches. Acetaldehyde, a chemical compound that our bodies produce when we digest alcohol, causes headaches as well. This chemical is also directly responsible for many other classic hangover symptoms, including nausea, increased skin temperature and lowered mood.

So what can you do? While no hangover cures exist, resting, drinking enough water, and eating simple, hearty foods like bread and eggs will help with symptoms. Over-the-counter pain medication should only be taken in small doses, and always check first if the medication is safe to take while hungover or drunk.

If you are worried you may be dependent on alcohol or have a substance use disorder, talk with your doctor or visit NorthShore’s Alcohol Abuse and Addiction Recovery Program.