The question everyone asks the morning after a big night: “When will this end?” The answer depends on a surprisingly complex set of factors, from how much you drank and what you drank to your age, genetics, and what you ate beforehand.
In this guide, we will walk through the typical timeline of a hangover hour by hour, explain what influences how long yours will last, and — critically — help you recognise when what feels like a hangover might actually be something more serious.
How Long Does a Typical Hangover Last?
For most people, a hangover begins several hours after you stop drinking (usually when your blood alcohol concentration approaches zero) and lasts anywhere from 12 to 24 hours. The peak of symptoms typically occurs around 12 to 14 hours after your last drink, and most people feel significantly better by the 24-hour mark.
However, this is a broad generalisation. Mild hangovers from moderate drinking might resolve in 6 to 8 hours. Severe hangovers from heavy drinking can persist for 48 hours or even longer. There is enormous variation from person to person and from one drinking occasion to the next.
The Hour-by-Hour Timeline
The following timeline assumes a common scenario: you finished your last drink around midnight after a night of moderate-to-heavy drinking (roughly 8 to 12 standard drinks over 5 to 6 hours).
Midnight to 3:00 AM — Still Intoxicated
What is happening: Your blood alcohol concentration (BAC) is still elevated. Your liver is working hard, processing roughly one standard drink per hour. You are likely still feeling the effects of intoxication — impaired coordination, lowered inhibitions, and possibly euphoria.
What you might notice:
- Feeling drunk or buzzed
- Frequent trips to the bathroom (alcohol’s diuretic effect is in full swing)
- Possibly eating late-night food
- Falling asleep (though the quality will be poor)
Behind the scenes: Your body is losing water and electrolytes at an accelerated rate. Acetaldehyde (the toxic byproduct of alcohol metabolism) is building up. Your vasopressin levels are suppressed, sending extra fluid to your bladder. Inflammatory processes are ramping up.
3:00 AM to 6:00 AM — The Disrupted Sleep Phase
What is happening: As your BAC drops, your brain enters a “rebound” phase. The sedative effects of alcohol are wearing off, and your nervous system is swinging in the opposite direction — becoming more excitable.
What you might notice:
- Waking up repeatedly (sleep fragmentation)
- Feeling hot or sweaty
- Vivid or unsettling dreams
- Racing heart
- Feeling anxious or restless
- Desperately thirsty
Behind the scenes: REM sleep rebound is occurring — your brain is trying to catch up on the REM sleep it missed earlier in the night, leading to vivid dreams. Your blood sugar is dropping as your liver diverts resources to alcohol metabolism. Dehydration is worsening.
6:00 AM to 9:00 AM — The Hangover Arrives
What is happening: Your BAC is nearing zero or has already reached it. Paradoxically, this is when you start feeling the worst. The hangover is not caused by having alcohol in your system — it is caused by your body’s reaction to its absence and the accumulated damage from processing it.
What you might notice:
- Pounding headache
- Nausea (possibly vomiting)
- Intense thirst and dry mouth
- Fatigue despite having been in bed for hours
- Sensitivity to light and sound
- Dizziness
Behind the scenes: Dehydration is at its peak. Acetaldehyde levels may still be elevated. Inflammatory cytokines are circulating in high concentrations. Your brain is dealing with neurotransmitter imbalance — GABA is low, glutamate is high. Blood sugar remains low.
9:00 AM to 12:00 PM — Peak Misery
What is happening: This is typically the worst phase of a hangover. All of the body’s recovery mechanisms are working simultaneously, and the combined effects are at their maximum.
What you might notice:
- All symptoms at their most intense
- Difficulty concentrating or thinking clearly (brain fog)
- Muscle aches and weakness
- Irritability or low mood
- “Hangxiety” — feelings of anxiety, regret, or dread
- Loss of appetite despite needing food
- Possible stomach cramps or diarrhoea
Behind the scenes: Your immune system is in full inflammatory mode. Oxidative stress is high as your body deals with free radicals generated by alcohol metabolism. Electrolyte imbalance is affecting muscle and nerve function. The gut lining is inflamed and more permeable than usual.
12:00 PM to 3:00 PM — The Slow Turn
What is happening: If you have been hydrating, eating, and resting, your body is beginning to turn a corner. Acetaldehyde levels have dropped, hydration is improving, and the inflammatory response is starting to ease.
What you might notice:
- Headache beginning to fade
- Nausea subsiding
- Appetite slowly returning
- Still fatigued but less intensely
- Mental clarity starting to improve
- Mood lifting slightly
Behind the scenes: Your liver has largely finished processing the alcohol and its byproducts. Electrolyte levels are beginning to normalise (especially if you have been eating and drinking appropriately). Inflammatory markers are declining.
3:00 PM to 6:00 PM — Recovery Mode
What is happening: Most people are feeling noticeably better by this point. The body is in active recovery mode — repairing damage, restoring nutrient levels, and recalibrating neurotransmitter balance.
What you might notice:
- Feeling “functional” again, if not fully normal
- Residual tiredness
- Able to eat normally
- Mild headache may linger
- Mood largely returned to normal
- Craving comfort food or specific nutrients
Behind the scenes: Hydration and electrolyte levels are close to normal. The inflammatory response has largely resolved. Blood sugar has stabilised. However, your body is still running a sleep deficit that will not fully resolve until you get a proper night’s rest.
6:00 PM to Midnight — The Tail End
What is happening: By the evening, most hangovers from a single night of moderate-to-heavy drinking have largely resolved. You may feel tired earlier than usual and crave an early night.
What you might notice:
- Feeling mostly normal
- Ready for sleep earlier than usual
- Possible lingering fatigue
- Appetite fully returned
- Mild residual brain fog
Behind the scenes: Your body is prioritising recovery sleep. Neurotransmitter levels are rebalancing. Most inflammatory markers have returned to baseline. Full recovery — including the sleep debt — will be complete after a good night’s rest.
Factors That Affect How Long Your Hangover Lasts
No two hangovers are identical. Here are the key variables that determine whether you are back on your feet by lunchtime or still suffering at dinner.
Amount Consumed
This is the single biggest factor. More alcohol means more acetaldehyde to process, more dehydration, more electrolyte loss, and more inflammation. The relationship is roughly proportional: doubling the amount you drink can more than double the duration and intensity of your hangover.
The Australian guidelines suggest no more than 4 standard drinks on a single occasion to reduce the risk of injury. Exceeding this significantly increases both the likelihood and severity of a hangover.
What You Drank
As discussed in our article on the science of hangovers, drinks high in congeners (dark spirits, red wine, brandy) tend to produce longer-lasting, more severe hangovers than low-congener options (vodka, white wine, gin) at the same alcohol volume. Mixing different types of drinks can also worsen outcomes, partly because it makes it harder to track how much you have consumed.
Body Weight and Composition
Larger bodies have more water to dilute alcohol, resulting in lower blood alcohol concentrations. Body composition matters too — people with higher body fat percentages have less body water relative to their weight, meaning they effectively concentrate the alcohol more.
Age
Hangovers get worse as you get older. This is not just a perception — several biological factors are at play:
- Liver enzyme efficiency declines. Your liver becomes slower at processing alcohol and its toxic byproducts.
- Body water decreases. Total body water declines with age, meaning the same amount of alcohol produces a higher BAC.
- Recovery capacity diminishes. Your body’s overall ability to repair tissue damage, reduce inflammation, and restore homeostasis slows down.
- Sleep quality declines. Alcohol’s disruption of already-less-efficient sleep patterns creates a compounding effect.
Many people find that hangovers that were manageable in their twenties become genuinely debilitating in their thirties and forties.
Hydration Before and During Drinking
Starting a drinking session already dehydrated — which is common in Australia’s warm climate — means you are beginning with a deficit. Similarly, failing to drink water between alcoholic drinks allows dehydration to compound more rapidly.
People who alternate alcoholic drinks with glasses of water consistently report shorter, milder hangovers. This does not prevent a hangover entirely, but it meaningfully reduces severity.
Food Intake
Eating before and during drinking slows the absorption of alcohol into your bloodstream, resulting in a lower peak BAC and giving your liver more time to process each unit. Drinking on an empty stomach leads to rapid absorption, higher BAC peaks, and worse hangovers.
The type of food matters too. Meals containing fat, protein, and complex carbohydrates slow absorption most effectively.
Sleep Duration and Quality
Alcohol-disrupted sleep is a major contributor to hangover duration and severity. If you managed only four or five hours of fragmented sleep, your hangover will feel worse and last longer than if you had the luxury of sleeping in. The sleep deficit compounds the fatigue, brain fog, and mood disturbance caused by the hangover itself.
Genetics
Genetic variation in the enzymes that process alcohol (ADH and ALDH2) significantly affects hangover duration. People with less efficient variants of these enzymes accumulate more acetaldehyde and take longer to clear it, resulting in longer, more intense hangovers. This is largely beyond your control, but it is useful to know that genetic factors explain much of the variation in hangover experiences between individuals.
Medications
Certain medications can interact with alcohol and prolong hangover symptoms. Antihistamines, antidepressants, blood pressure medications, and diabetes medications can all affect how your body processes alcohol. If you take regular medication, it is worth discussing alcohol interactions with your doctor or pharmacist.
Two-Day Hangovers: Why They Happen
The dreaded two-day hangover is a real phenomenon, and it becomes more common with age and heavy consumption.
Why Some Hangovers Last More Than 24 Hours
- Sheer volume. If you consumed a very large amount of alcohol, your liver may take well over 24 hours to fully process all the acetaldehyde and restore normal function.
- Severe dehydration. Profound dehydration takes longer to correct than mild dehydration. If you lost a lot of fluid and did not replenish adequately on day one, symptoms can persist.
- Sleep debt. One night of recovery sleep may not be enough to compensate for a night of severely disrupted sleep, especially if you are already running a sleep deficit.
- Prolonged inflammation. Heavy drinking can trigger an inflammatory response that takes more than 24 hours to fully resolve.
- Gut recovery. If alcohol significantly damaged your gut lining, it may take two to three days for your digestive system to return to normal.
- Nutrient depletion. Replenishing heavily depleted stores of B vitamins, magnesium, and zinc can take more than a day.
Day Two Symptoms
Second-day hangover symptoms are typically different from day one. The acute symptoms (headache, nausea, dizziness) have usually resolved, but you may still experience:
- Persistent fatigue and low energy
- Brain fog and difficulty concentrating
- Low mood or anxiety
- Digestive issues (bloating, irregular bowel movements)
- Muscle aches
- Poor appetite
These are largely the aftereffects of sleep disruption, nutrient depletion, and residual inflammation. Rest, nutritious food, hydration, and time are the remedies.
When a Hangover Might Be Something More Serious
While hangovers are unpleasant, they are generally not dangerous. However, there are situations where what seems like a hangover could indicate a more serious medical issue.
Warning Signs That Require Immediate Medical Attention
Call 000 or go to your nearest emergency department if you or someone you are with experiences:
- Seizures or convulsions. Alcohol withdrawal can cause seizures in people who are physically dependent on alcohol. This is a medical emergency.
- Severe, uncontrollable vomiting (especially if there is blood in the vomit). This could indicate gastrointestinal bleeding.
- Confusion or disorientation beyond normal brain fog. Severe confusion could indicate alcohol poisoning, hypoglycaemia, or other dangerous conditions.
- Chest pain or difficulty breathing. Alcohol can trigger cardiac arrhythmias or exacerbate underlying heart conditions.
- Loss of consciousness or inability to wake someone. This could be alcohol poisoning, which is potentially fatal.
- Very slow or irregular breathing. Fewer than 8 breaths per minute or gaps of more than 10 seconds between breaths is a medical emergency.
- Hypothermia. Cold, clammy, pale, or blue-tinged skin indicates dangerously low body temperature.
Signs You Should See a Doctor Soon
Book an appointment with your GP if you experience:
- Hangover symptoms lasting more than 72 hours. A hangover that does not resolve within three days may indicate a more significant health issue.
- Persistent abdominal pain. This could indicate gastritis, pancreatitis, or other gastrointestinal problems exacerbated by alcohol.
- Yellowing of the skin or eyes (jaundice). This is a sign of liver problems that requires medical evaluation.
- Regularly experiencing severe hangovers. Frequent, debilitating hangovers may indicate that your drinking patterns are causing cumulative harm. Your GP can provide confidential assessment and support.
- Tremors or shaking that worsens over time. While mild tremors can be a normal part of a hangover, worsening tremors may indicate alcohol withdrawal.
- Persistent mood changes. If you notice ongoing depression, anxiety, or mood disturbances after drinking, this is worth discussing with a healthcare professional.
When Hangovers Become a Pattern
If you find that hangovers are a regular part of your life — weekly or more frequently — it is worth taking an honest look at your relationship with alcohol. Frequent hangovers are a clear signal that you are regularly consuming more than your body can comfortably handle.
This does not necessarily mean you have an alcohol use disorder, but it does mean your body is being put under repeated stress. Over time, this cumulative damage can lead to:
- Liver damage (fatty liver, hepatitis, cirrhosis)
- Increased cancer risk
- Cardiovascular problems
- Mental health deterioration
- Weakened immune function
- Nutritional deficiencies
The Australian Department of Health recommends no more than 10 standard drinks per week and no more than 4 on any single occasion. If you are regularly exceeding these guidelines and experiencing frequent hangovers, it may be time to make a change.
How to Shorten Your Hangover
While you cannot make a hangover disappear instantly, you can take steps to speed recovery.
Hydrate Aggressively
Start drinking water or an electrolyte solution as soon as you wake up. Sip consistently rather than gulping large amounts at once, as this is easier on your stomach and allows your body to absorb the fluid more effectively. Coconut water and oral rehydration solutions are particularly good choices.
Eat Nutrient-Dense Food
Even if you do not feel like eating, getting food into your system is one of the most effective recovery strategies. Eggs, bananas, toast with Vegemite, and oats are all excellent choices. The sooner you eat, the sooner your blood sugar stabilises and your body gets the raw materials it needs for recovery.
Rest and Sleep
If you can, go back to bed. Your body did not get proper sleep during the night, and quality rest is one of the most powerful recovery tools available. Even a couple of hours of proper daytime sleep can dramatically shorten a hangover.
Manage Pain Carefully
If your headache is severe, paracetamol (acetaminophen) is generally considered the safer option during a hangover. Avoid aspirin and ibuprofen on an empty stomach, as they can worsen gastric irritation. Do not take paracetamol if you are still intoxicated or are a heavy drinker, as the combination can be harmful to the liver. Follow the dosage instructions on the packaging.
Get Fresh Air and Light Exercise
Gentle movement — a short walk, some light stretching — can help boost circulation and mood without overtaxing your depleted body. This is not the day for a gym session, but getting off the couch and moving gently can help you feel better.
Getting Support
If you are concerned about your drinking or finding it difficult to moderate your alcohol consumption, you do not have to figure it out alone. The National Alcohol and Other Drug Hotline is available 24/7 on 1800 250 015. It is free, confidential, and staffed by trained counsellors who can provide information, advice, and referrals to local support services.
You can also speak with your GP, who can provide a confidential assessment and discuss options tailored to your situation.
The Bottom Line
A typical hangover lasts 12 to 24 hours, with symptoms peaking around 12 to 14 hours after your last drink. The duration is influenced by the amount consumed, what you drank, your age, genetics, hydration status, food intake, and sleep quality. Two-day hangovers happen and become more common with age and heavy consumption.
Most hangovers, while unpleasant, resolve on their own with rest, hydration, and nutritious food. However, certain symptoms — seizures, severe vomiting, confusion, chest pain, or loss of consciousness — require immediate medical attention. And if hangovers are a regular part of your life, that is a signal worth paying attention to.
The most reliable way to avoid a hangover is, of course, to drink less. But when you do choose to drink, pacing yourself, eating beforehand, staying hydrated, and getting adequate sleep will all help keep the aftermath manageable.
Health Disclaimer: This article is for informational purposes only and does not constitute medical advice. The information provided is based on general medical knowledge and should not be used as a substitute for professional medical diagnosis or treatment. Hangover symptoms can sometimes mask or mimic more serious medical conditions. If you are concerned about your symptoms or your alcohol consumption, please consult a qualified healthcare professional. In a medical emergency, call 000 immediately.