A hangover feels like your body is fighting you on every front at once: a throbbing headache, a churning stomach, bone-deep fatigue, and a mental fog that makes simple tasks feel overwhelming. Symptoms typically begin as your blood alcohol level drops toward zero, often hitting hardest the morning after drinking. The experience ranges from mildly unpleasant to completely debilitating, depending on how much you drank, what you drank, and your individual biology.
The Physical Symptoms
The most common physical sensations during a hangover are fatigue, thirst, and headache. These three tend to dominate the experience. Muscle aches are common too, along with a general sense of weakness that can make it hard to get out of bed. Your body may feel heavy and sluggish in a way that goes beyond ordinary tiredness.
Stomach symptoms are often the most disruptive part. Alcohol directly irritates the stomach lining and triggers extra acid production, which leads to nausea, stomach pain, and sometimes vomiting. Some people describe a rolling, low-grade queasiness that lasts for hours. Others have sharper waves of nausea that come and go. Eating can feel both necessary and impossible.
Sensory sensitivity is another hallmark. Light feels too bright, sounds feel too loud, and your surroundings can seem almost aggressive. Vertigo or dizziness is possible, especially when you stand up quickly. Some people notice their heart beating faster than usual, along with sweating and a slight tremor in their hands. These are signs your nervous system is in a revved-up state as it rebounds from alcohol’s sedating effects, and they can feel alarming if you’re not expecting them.
The Mental and Emotional Side
A hangover isn’t just physical. Sleepiness, difficulty concentrating, and a foggy, slow-moving mind are among the most frequently reported symptoms, and research shows they also rank among the most severe. In one study measuring how individual symptoms affect daily functioning, concentration problems had the single largest impact on cognitive performance, scoring 3.1 out of 5 on a cognitive functioning impact scale. Being tired and sleepy had the biggest overall impact across all domains.
Irritability is common. Small frustrations that you’d normally brush off can feel disproportionately annoying. Some people experience anxiety the day after drinking, sometimes called “hangxiety.” About 23% of people in one large survey reported anxiety as a hangover symptom. While it’s less common than headache or fatigue, it can be one of the more unsettling parts of the experience, especially if you’re not sure why you feel a vague sense of dread with no clear cause. Depression-like feelings are reported even less frequently, but they do occur.
Why Your Body Feels This Way
Several things are happening at once inside your body during a hangover. When your liver breaks down alcohol, it produces a toxic byproduct that your body then has to process further. If you’ve consumed more alcohol than your liver can efficiently handle, that intermediate toxin builds up and contributes to feeling sick.
Alcohol also suppresses the hormone that tells your kidneys to hold on to water. This is why you urinate more when drinking, and the resulting mild dehydration contributes to thirst, fatigue, and headache the next day. At the same time, alcohol triggers an inflammatory immune response. Your body releases the same signaling molecules it uses to fight infections, which can cause muscle aches, fatigue, and difficulty concentrating, much like the early stages of a cold or flu.
Your stomach is dealing with direct chemical irritation from the alcohol itself, plus a spike in acid production. And your nervous system, which alcohol suppressed during the evening, overcorrects the next day. It shifts into a more activated state, which explains the increased blood pressure, rapid heartbeat, sweating, and that jittery, on-edge feeling many people notice.
How Sleep Disruption Makes It Worse
Even if you slept a full eight hours after drinking, you probably didn’t get good sleep. Alcohol changes the architecture of your sleep in a specific pattern: during the first half of the night, it acts as a sedative, knocking you into deep sleep quickly and delaying the lighter, dream-filled sleep stages. But in the second half of the night, as your blood alcohol drops, a rebound effect kicks in. You spend more time in lighter sleep stages and wake up more often, sometimes without remembering it.
The result is that you wake up feeling unrested despite technically being in bed long enough. Research has found that the number of nighttime awakenings and overall sleep quality both correlate with hangover severity. This disrupted sleep compounds the cognitive effects of alcohol’s other hangover mechanisms, making the brain fog, poor concentration, and fatigue worse than either factor would cause alone.
What You Drank Matters
Not all alcoholic drinks produce the same hangover. Darker spirits like bourbon, brandy, and red wine contain higher levels of congeners, which are complex byproducts of fermentation. Bourbon contains roughly 37 times the amount of congeners as vodka. In controlled studies where participants drank equivalent amounts of alcohol, those who drank bourbon reported significantly more severe hangovers than those who drank vodka. The effect size was moderate, meaning it’s a real and noticeable difference, though the total amount of alcohol consumed still matters more than the type.
Clear spirits like vodka and gin tend to produce milder hangovers at the same dose. This doesn’t mean they’re hangover-proof. Any amount of alcohol above what your body can comfortably process will cause symptoms. But if you’ve noticed that red wine or whiskey hits you harder the next morning than the same number of drinks in vodka, that’s not your imagination.
How Age Changes the Experience
There’s a widespread belief that hangovers get worse as you age, but research tells a more surprising story. A large study examining hangover severity across age groups found that younger drinkers actually report more severe hangovers than older drinkers, even after controlling for how much alcohol was consumed. The correlation between increasing age and decreasing hangover severity was strong and statistically significant.
Several factors likely explain this. Pain sensitivity gradually declines with age, meaning the same physical discomfort registers as less intense. Older drinkers may also have more realistic expectations about how intoxication and its aftermath feel, leading to more moderate self-assessments. And younger drinkers tend to report feeling more subjectively intoxicated at the same blood alcohol levels, which itself predicts worse hangover ratings. When researchers controlled for subjective intoxication, the age difference in hangover severity disappeared entirely.
How Long It Lasts
Hangover symptoms typically begin within several hours of your last drink, as your blood alcohol concentration drops toward zero. For most people, they peak in the morning and gradually improve over the course of the day. A mild hangover from moderate drinking might clear up by early afternoon. A severe hangover after heavy drinking can linger for a full 24 hours, with fatigue and mild stomach discomfort sometimes stretching into the following day.
The timeline varies based on how much you drank, how quickly you drank it, whether you ate beforehand, how well you slept, and your individual metabolism. There’s no reliable way to speed up the process. Your body needs time to clear the toxic byproducts, rehydrate, calm the inflammatory response, and restore normal nervous system balance. Staying hydrated and eating bland foods can ease the discomfort, but the underlying biology runs on its own clock.