What is a hangover?

Alcohol hangover imageAn alcohol hangover refers to the mental, emotional and physical symptoms which an individual experiences after they have consumed alcohol. A hangover occurs when the person has recovered from the intoxicating effects of alcohol – that is, when the body has metabolised or processed the alcohol consumed and is sober. People usually suffer from a hangover the morning after they consumed alcohol. Sometimes, however, the person will still be intoxicated when they wake up and will not experience a hangover until they are sober again.
Anyone who has experienced a hangover would probably describe it as an unpleasant experience. It can last anywhere between 8 and 24 hours, and disrupt daily tasks and responsibilities such as going to work, looking after kids or enjoying time with friends and family.
A hangover is also a good sign that you drank too much – that is, you’ve consumed so much alcohol that it might present health risks, including damaging your brain. It’s not surprising that people who report a greater number of hangovers show damage to brain structures.

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This tool can be used to provide a rough estimate of your individual blood alcohol concentration (BAC) after consuming a defined amount of alcohol in a single sitting. Please remember this is an estimate and it will not be 100% accurate, as there are a wide range of factors that can affect BAC in individuals (such as the amount of food eaten, type of drinks consumed and metabolic rate) and these are not taken into consideration when using this tool. Therefore, under no circumstances should this tool be used to determine whether you should drive. The only way to be totally sure that you remain under the legal BAC limit is not to drink any alcohol at all.


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  1. Do you know when to stop? A driver‘s guide to staying under 0.05 BAC [online]. Canberra, ACT: Australian Transport Safety Bureau; 2011 [cited February 2011]. Available from: URL link
  2. Alcohol and its effects [online]. Parkside, SA: Government of South Australia Health, Drug and Alcohol Services; 2010 [cited February 2011]. Available from: URL link


Hangover symptoms

Hangovers produce a range of unpleasant physical, mental and emotional symptoms that combine to create an overall feeling of poor wellbeing. Each person will experience a hangover differently, but there are some common symptoms.

Physical symptoms

The physical symptoms of a hangover can include:

Mental symptoms

Alcohol hangover imageThe mental symptoms of a hangover can include:

  • Dizziness;
  • Vertigo;
  • Irritability;
  • Changes to visual perception;
  • Poor performance on identification tasks;
  • Difficulty paying attention, staying alert, reacting and processing information;
  • Reduced coordination, including hand–eye and limb coordination;
  • Poor memory and recall; and
  • Poor performance with task-driven activities.

Emotional symptoms

Some people will experience depression, anxiety and/or irritability when they have a hangover, and the more you consume, the more likely you are to experience these emotional symptoms.
However, emotional changes may be indirect effects of a hangover, caused not by the effects of alcohol itself, but by the physical and emotional symptoms of the hangover. For example, a study showed that a person’s mood deteriorates throughout the morning when they have a hangover, making them more prone to be depressed, anxious or irritable as the day wears on. As these disturbed moods only occur as the day progresses, not immediately when the person becomes sober, scientists believe that hangover symptoms such as headaches and difficulty remembering and processing information cause anxiety and depression, rather than the alcohol itself.

Who gets a hangover?

Hangovers are a common side effect of drinking to intoxication. People who drink heavily more often are more likely to experience hangovers. The more intoxicated one becomes, the more severe a hangover is likely to be. For example, one study reported that the greater the concentration of alcohol in a person’s body, the more severe their hangover. Peak alcohol concentration refers to the highest concentration alcohol reaches in your body body when you are intoxicated. It is believed to be a better predictor of hangover than the overall amount of alcohol consumed, adjusted to take into consideration your body weight. Hangovers also become more likely the longer the duration of alcohol consumption.
As such, the prevalence of hangovers is expected to be higher in populations that drink more heavily, including:

  • Stressed people: The more stressed a person, the more likely they are to drink larger quantities of alcohol;
  • Men: Men are more likely than women to consume intoxicating quantities of alcohol; and
  • Youth: Young people tend to binge drink more than their older counterparts.

Alcohol hangover imageHowever, not all people experience a hangover after moderate levels of alcohol consumption, and peak alcohol concentration does not reliably predict whether someone will experience a hangover. For example, one study reported that 76% of participants experienced a hangover the morning after moderate drinking (defined as a quantity of alcohol which caused their alcohol concentration to rise to 0.115 g%, much higher than the .05 level acceptable for driving). Other studies have reported 25–50% of participants did not experience a hangover after intoxication. Interestingly, a study on a group of people with alcohol dependence (alcoholism) determined that 50% of the participants had not experienced a hangover in the previous year.

What causes a person to feel hungover?

Studies indicate that factors other than the quantity of alcohol consumed also influence whether a hangover is experienced. However, the causes of hangovers remain poorly understood. It is not clear whether a hangover is a direct effect of alcohol, the aftereffects of alcohol, or a combination of the two. Non-alcohol factors such as changes in sleep and eating patterns associated with alcohol intoxication may also play a role.
Researchers have identified a number of factors which potentially play a role in hangovers and may make some people more susceptible to hangovers, including:

Beverage congener content

Alcohol hangover imageCongeners are a common ingredient in dark alcoholic beverages, including dark spirits and red wine. Alcoholic beverages with a high congener content appear to cause more severe hangovers than those with a low congener content. One study reported that individuals who became intoxicated drinking bourbon reported more severe hangovers the following day than individuals who became intoxicated drinking vodka. However, there were no differences between a bourbon and vodka drinker on mental tests performed the following day.
Another study found a lower prevalence of hangover in participants drinking low congener alcohols (white wine, gin, vodka, pure ethanol) compared to participants who drank high congener alcohols (e.g. brandy, whiskey and red wine).

Congeners For more information, see Congeners in Alcoholic Beverages.

Biological differences

Biological differences (e.g. physical and mental differences) which affect an individual’s response to alcohol might also affect the incidence and severity of hangover. These include:

  • Personality and temperament: Some aspects of personality or temperament have been reported to affect the likelihood of hangover, including personality traits such as neuroticism, anger and defensiveness;
  • Family history of alcoholism and other risk factors for alcohol dependence: Has been found to increase the likelihood and severity of hangover. The reasons for this are not well understood, although some researchers believe it is because individuals at greater risk of alcohol dependence may experience more acute hangover symptoms and drink further alcohol to treat such symptoms, and in doing so increase their chances of developing alcohol dependence; and
  • Metabolism.

Metabolism of methanol

The rate at which an individual metabolises methanol (a congener commonly found in alcoholic drinks which produces formic acid and formaldehyde when it is broken down in the body) is thought to influence the experience of hangover. People who metabolise methanol more quickly are thought to experience more severe hangover symptoms. While no studies have examined methanol metabolism, evidence regarding the effects of methanol and the way in which it is broken down by the body support this hypothesis.
Drinks with a higher methanol content are associated with a greater likelihood of hangover, and hangover occurs at the same time the body begins metabolising methanol. In addition, administering ethanol (alcohol), which stops methanol being broken down to formic acid and formaldehyde, reduces the symptoms of a hangover (note that this should not be used as a treatment).

Metabolism of ethanol

The production of toxic by-products occurs in ethanol metabolism. Acetaldehyde is one such metabolite which has toxic effects on the body in high concentrations. For most people, the acetaldehyde is quickly metabolised and has little time to cause toxic symptoms. However, slow metabolisers can retain acetaldehyde for longer and, because of this, may experience symptoms typical of a hangover such as:

  • Rapid pulse;
  • Sweating;
  • Skin flushing;
  • Nausea; and
  • Vomiting.

Psychological factors

Alcohol hangover imagePsychological factors influence a person’s experience of hangover. Individuals with psychological problems report experiencing more severe hangovers after drinking to intoxication. These factors include:

  • Guilt about alcohol consumption;
  • Having a neurotic personality;
  • Being angry or defensive;
  • Becoming angry or depressed whilst intoxicated;
  • Having experienced a negative life event; and
  • Personality traits associated with a high risk for alcoholism.

These factors have been found in some studies to be more important determinants of hangover symptoms than the amount of alcohol consumed. As only 50–75% of people who drink alcohol to intoxication experience hangovers and many studies have shown no relationship between peak blood alcohol concentrations, these findings are plausible.

Gastrointestinal disturbances

Alcohol causes gastrointestinal disturbances such as:

  • Irritation of stomach and intestines;
  • Gastritis (inflammation of stomach lining);
  • Increased production of gastric acid; and
  • Increased production of intestinal secretions.

The gastrointestinal disturbances can cause abdominal pain, nausea and vomiting.

Diuretic effect of alcohol

Alcohol is a diuretic, which means it causes the body to expel more urine than usual. Consumption of four alcoholic drinks causes the elimination of 600-1,000 mL of urine. Alcohol affects the body’s hormone production system and reduces the effect of the anti-diuretic hormone which prevents the expulsion of urine by triggering the kidneys to reabsorb water. When the kidneys do not reabsorb water, the water is expelled and the person urinates more often.

Low blood sugar

A decrease in blood sugar levels is an effect of alcohol consumption. The by-products of alcohol can inhibit glucose production, especially after binge drinking.
Excessive alcohol consumption, particularly when it is coupled with poor nutritional intake, can lead to hypoglycaemia (low blood glucose levels). The resulting hangover effects include weakness, fatigue and mood disturbances.

Alcohol withdrawal

Hangovers are thought to affect the brain in a similar way to alcohol withdrawal, which is the experience an alcoholic has if they do not consume alcohol. The symptoms of both hangovers and alcohol withdrawal are alleviated if the person is given more alcohol.
Scientists believe that the body compensates for alcohol’s sedative effect by changing the way the brain responds, making it more responsive to excitatory stimuli and less responsive to stimuli which usually have an inhibitory effect. Effectively, the brain copes with alcohol by becoming hyper-excited. Once alcohol has been eliminated from the system, the brain remains in a hyper-excited state which induces tremor, sweating and rapid heartbeat.

Sleep deprivation

Alcohol hangover imageSleep deprivation is a major contributing factor to a hangover and as such correlates significantly with emotional, mental and physical symptoms.
Hormones that control the wake/sleep cycle (e.g. serotonin and glutamate) are affected by alcohol consumption. As the blood alcohol level (BAL) rises, an individual is more likely to stay awake. When the BAL decreases, it causes a sedative or sleepy effect.
Alcohol decreases the time it takes to fall asleep, but disturbs the natural sleep cycle. In the first half of sleep when the alcohol is being processed or metabolised:

  • The time spent in rapid eye movement (REM) or light sleep is greatly diminished; and
  • The time spent in slow wave or deep sleep is increased.

In the second half of sleep when the alcohol has been processed or metabolised:

  • The time spent in REM sleep is increased and sleep is lighter than usual;
  • The individual will experience increased wakefulness or difficulty sleeping.

The specific effects of sleep deprivation are complex and will depend on the amount of alcohol consumed and the time between consumption and sleep onset. In general, it can be said that alcohol consumption is associated with lighter, less efficient and more disturbed sleep. This will usually have a negative effect on the individual’s mood and thinking the next day.

Other drugs

Using other drugs such as cocaine and tobacco while drinking may increase the severity of hangover, and some drugs may produce their own hangover effect. The associations between combining alcohol and drug use, and the presence or severity of a hangover, are poorly understood.

Which ingredients in an alcoholic beverage cause a hangover?

Ethanol is alcohol, or the ingredient in alcoholic beverages that causes intoxication. However, it is not known whether alcohol plays a direct role in causing a hangover, or whether other ingredients or side effects of drinking alcohol cause the hangover. There are other chemicals contained in alcoholic drinks that are believed to play a role in the development of a hangover, in particular congeners.

Are hangovers more likely with some types of alcohol?

Alcohol hangover imageThere have been studies conducted to investigate whether different types of alcohol are more or less likely to cause a hangover or affect the severity of a hangover. Many scientists believe that the greater the congener content in the alcohol, the worse the hangover will be. While drinks with more congener content may increase the perceived intensity of a hangover, there is no evidence to suggest that they worsen next-day performance, sleep or thinking ability. These results suggest that a glass of champagne, or a glass of red wine with the same alcohol content, are equally likely to cause a hangover. However, you may feel worse after drinking red wine.
Headaches are more commonly experienced after red wine than white wine. The former is thought to increase serotonin and histamine levels more than the latter; the reason for this is unknown.

Preventing hangovers

The best way of preventing a hangover is by avoiding intoxication – in other words, abstaining from alcohol. Hangovers can also be avoided by reducing the amount of alcohol that is consumed and drinking in moderation.
In order to prevent a hangover, intoxication must be avoided. The National Health and Medical Research Council of Australia (NHMRC) recommends that in order to reduce the lifetime risk of harm (and injury) from drinking, healthy men and women should drink no more than two standard drinks on any day.

Convert your Drinks into Standard Serving Sizes
For an amount of alcohol, find out how many standard drinks it represents.
  1. National Health and Medical Research Council. Australian Guidelines to Reduce Health Risks from Drinking Alcohol. 2009. [cited 2 May 2014]. [URL Link]


People who accidentally drink to intoxication may prevent a hangover or reduce the severity of their hangover by rehydrating and taking anti-inflammatory painkillers before sleeping. Avoiding alcoholic beverages with a lot of congeners (e.g. brandy, red wine and whiskey) may also reduce the perceived severity of experiencing a hangover.

Hangover remedies

Ethical considerations

Testing the effectiveness of various ‘hangover cures’ has received little attention in the health profession. Some health professionals argue that finding a treatment is undesirable because hangovers act as a deterrent to intoxication. However, there is no evidence to suggest that the experience of a hangover deters a person from consuming alcohol, or that an effective hangover cure would lead to increased consumption.

Research into hangover cures

A limited number of high quality scientific studies have been conducted to assess the effectiveness of various preparations in relieving hangover symptoms, some with positive results:

  • In one study, taking γ linolenic acid from Borago officinalis (borage) the morning after intoxication reduced the overall hangover severity and the severity of headache, tiredness and laziness;
  • A yeast preparation (250 mg dried yeast, 0.5 mg thiamine nitrate, 0.5 mg pyridoxine hydrochloride, and 0.5 mg riboflavin) was found to reduce symptoms of restlessness, impatience and discomfort in another study; and
  • Tolfenamic acid, a prostaglandin inhibitor, has also been shown to reduce overall hangover symptoms and individual symptoms, including headache, nausea, vomiting, thirst, dry mouth, nervousness and tremor, compared to placebo.

However, these hangover remedies are not commercially available and further studies are needed to confirm that they are, in fact, effective.

Simple hangover cures

Alcohol hangover imageThere are many measures which are commonly thought to reduce the intensity of hangover symptoms, but which have not been assessed in scientific studies. These include:

  • Consuming fruit, fruit juice and other fructose- or glucose-containing foods (to date, the few studies which have examined the role of fructose have not shown any benefit in reducing hangover symptoms);
  • Consuming complex carbohydrates to counteract low blood sugar levels;
  • Antacids for gastrointestinal symptoms;
  • Sleep to ease the fatigue;
  • Consumption of non-alcoholic beverages for rehydration; and
  • Caffeine to counteract fatigue and malaise.

If you have a headache or muscles aches, taking aspirin or another NSAID may help. However, be careful using these medicines if you are nauseous.

Hair of the dog

It’s important not to drink more alcohol. While drinking more alcohol (a ‘hair of the dog’ drink) will temporarily relieve symptoms, it will increase toxicity in the long run and your symptoms may be worse when you sober-up again. Drinking to relieve the symptoms of a hangover can also lead to alcohol dependence.

Take note

It’s important to be aware that you may not be fit to drive a car or operate machinery while you have a hangover, as you are likely to be drowsy or have difficulty concentrating.

When to see a doctor about your hangover

If you have a bad hangover, you may wish to visit your doctor for advice about treating the symptoms and preventing future hangovers. This is particularly important if you have problems with your heart or arteries, as a hangover could make them worse. It’s also important if you often experience hangovers, as you may have alcohol dependence and need support from health professionals to reduce the amount you drink.
To find out more about whether your patterns of drinking put you at risk of alcohol dependence, complete the AUDIT questionnaire.

Hangovers and the workplace

In addition to the unpleasant physical, mental and emotional symptoms, hangovers are associated with diminished workplace performance and poorer grades. In particular, the effects of a hangover have been found to impair the workplace performance of pilots, drivers, skiers and managers.
Regardless of occupation, people who have a hangover are more likely to:

  • Be late;
  • Have an accident at work: This is especially dangerous for people who deal with machinery and other safety-sensitive operations;
  • Be absent from work;
  • Have lower morale while at work;
  • Perform their work poorly; and
  • Have disputes with peers and/or colleagues.

Not only does this affect the individual and their colleagues, but it also affects the business and the country’s economy as a whole. A survey conducted in 2008 indicated that 8% of Australian workers are negatively affected by a colleague’s drinking habit, and 3.5% of people need to work extra to compensate for the poor performance of these workmates. Using this data, researchers were able to estimate that the total cost to the Australian economy, as a result of absenteeism and poor work performance due to alcohol, was $453 billion per year.

More information

For more information on drinking alcohol, including drinking disorders and alcohol’s effect on the body, as well as some useful tools, see Alcohol and Drinking



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