What happens to your body when you drink alcohol

Do you really know what alcohol is doing in your body?

We all know that drinking alcohol to excess isn’t really part of a healthy lifestyle. Drinking more than the recommended guidelines can put you at risk of developing serious diseases, affect your brain health and make you prone to alcohol-related accidents.

You know about alcohol poisoning, hangovers and brain damage, but did you know about the other ways alcoholic drinks can affect your body?

1. Congeners make your hangover worse

Scientific study of hangovers is still ongoing, but one thing we do know is that ‘congeners’ in alcohol can contribute to making your hangover worse.

Congeners are chemicals that occur naturally during the distilling and fermentation processes of alcohol creation and are found in greater amounts in darker coloured drinks, like red wine, bourbon and brandy. Congeners irritate blood vessels and tissues in your brain, which can make your hangover worse.

2. Sulphites trigger allergies and asthma

Sulphites are a mineral which occur naturally in a lot of foods and drinks, and can also be added as a preservative to stop spoilage and preserve colour. Some people are sensitive to sulphites, experiencing allergic reactions ranging from mild hay fever-like symptoms to serious anaphylactic reactions when they eat or drink them. People with asthma can also find that foods and drinks with high sulphite levels can trigger the condition.

Alcoholic drinks like wine and cider, and drinks you might mix with alcohol like concentrated fruit drinks and bottled lemon or lime juices, can contain high levels sulphites. If you’re feeling particularly sneezy, stuffy, wheezy or itchy after a night drinking, sulphites might be to blame.

3. Alcohol makes you sleep badly and gives you nightmares

You might think that alcohol makes you sleep better because it makes you drowsy, but it turns out alcohol actually lessens your sleep quality.

Alcohol disrupts your sleep cycle, and can interfere with your REM sleep. REM sleep is the sleep stage where you’ll often have vivid dreams or nightmares, which means when alcohol affects your REM it can bring on bad dreams.

4. Your hangover can trigger anxiety

As your body gets alcohol out of your system, your blood sugar levels drop, which actually stresses your brain out. This can lead to feelings of anxiousness and worry, and can be especially triggering if you have an anxiety disorder.

Lots of people drink to relax and rid themselves of worries or anxiety for a few hours, but if your hangover comes with a hefty dose of anxiousness, you might need to rethink this coping mechanism.

5. Drinking alcohol raises your risk of mouth, throat, larynx and oesophagus cancer

Many people know that drinking alcohol can raise your risk of cancers like liver, breast and bowel cancer. But it can also increase your chances of developing cancer of the mouth, throat, larynx or oesophagus.

Ethanol, which is what alcohol is made of, isn’t carcinogenic in itself, but when your body metabolises it, it turns into acetaldehyde, which the International Agency for Research on Cancer lists as a Group 1 carcinogen to humans.

For further reading, Cancer Research UK has information about how alcohol can cause cancer.

6. Alcohol absorbs, but doesn’t digest

Did you know you don’t actually digest alcohol when you drink it? Instead, once hitting your stomach, it absorbs straight into your bloodstream.

The rate at which your body absorbs alcohol depends on a number of factors, including your weight and body type and how much food is already in your stomach. This is why it’s important to eat a meal before you start drinking, even though alcohol won’t be digested with your food.

7. It stops you from creating memories (rather than making you forget)

If you’ve ever drunk so much that you’ve ‘blacked out’ and woken up the next day not knowing what you did the night before, you might think that the alcohol has made you forget what happened.

But alcohol doesn’t make your brain forget the memories; it impedes its abilities to make new memories while you’re drunk. It particularly affects your ability to make new long-term memories, which means you might “remember” what’s going on in the short-term while you’re drinking, like remembering that your friend has just arrived at the party, but those memories might not be there in the morning when they haven’t translated across to your long-term memory.

8. Alcohol can cause inflammation of your stomach lining

Ever get diarrhoea with your hangover? Yep, you can blame alcohol for that one, too. Alcohol makes your stomach produce more acid, which can cause your stomach lining to become inflamed, a condition called gastritis.

9. Alcohol actually makes you colder

Alcohol is a ‘vasodilator’, which means it opens up your blood vessels, including the small capillaries under the surface of your skin. This is why you might feel warm when you’ve been drinking, because more of your blood has come to the surface of your body. But this also means that your body’s core temperature drops as the warm blood moves away, so even though you’re feeling warm, your body is actually getting colder.

10. Drinking makes you crave junk food

There are a number of reasons why you might crave salty or fatty foods when you’ve been drinking. Going back to gastritis from a few points ago, fatty foods will line your stomach, protecting it from the excess acid and making you feel less ill.

You’re also likely to be dehydrated if you’ve been drinking, because alcohol is a diuretic and makes you pee a lot. You might crave salty foods which will replenish your body’s electrolytes and help your body store lost water.

Scientists also think there might be a link to the way alcohol acts on your brain and your desire to eat. Their hypothesis is that alcohol activates the brain cells that normally tell you you’re hungry, making you want food whether you need it or not.

Last updated: 20 July 2020

Many of us drink alcohol to relax and socialise. But drinking too much alcohol can negatively affect your physical and mental health, your actions, and your decision-making. There are many short and long-term side effects of alcohol consumption.

Why is alcohol a health issue?

Many Australians drink some alcohol. Some people drink alcohol in amounts that are harmful to their health. This kind of drinking can cause death, disease, and injury. This is a major factor in ill health and social harm in Australia.

One standard drink contains 10 grams of pure alcohol, which is found in (approximately):

• 285ml full-strength beer or cider
• 375ml mid-strength beer
• 425ml light-strength beer
• 100ml wine
• 1 nip (30ml) of spirits

No level of alcohol consumption can be considered safe. To reduce the risk of harm from alcohol-related disease or injury for healthy adults:

• drink no more than 10 standard drinks per week
• drink no more than 4 standard drinks on any one day

But some people need to take more care. You are at greater risk of harm from alcohol if you are:

• under the age of 18 years
• older than 65 years
• taking other medicines or drugs
• engaging in a risky activity such as driving or operating machinery

During pregnancy, and while breastfeeding, no level of drinking is considered safe for the baby.

Drinking heavily can put you at risk of short-term injury or illness. The negative side effects of alcohol can also accumulate, harming your health over your lifetime.

To avoid the negative effects of alcohol, you should practice safe drinking and manage your alcohol intake.

What are the short-term health effects of alcohol?

In Australia, 1 in 3 people drink more than they should on a single occasion. This is commonly referred to as ‘binge drinking’ (drinking more than 4 standard drinks on any one occasion).

In the short term, drinking too much alcohol can cause side effects, including:

• dizziness
• lack of judgement
• loss of coordination
• memory loss
• vomiting
• accidental injury (to yourself or others)
• being in a road accident
• deliberately harming yourself or others
• alcohol poisoning (which can be fatal)
• fatigue (tiredness)
• headaches
• hangover

What are the long-term health effects of alcohol?

Drinking more than 2 standard drinks a day can seriously affect your physical and mental health over your lifetime.

The side effects of alcohol include dependence and addiction, especially in people who have depression or anxiety. It can also increase the risk of suicide.

Regular, heavy alcohol consumption can also result in unhealthy weight gain. Even drinking small amounts of alcohol increases your cancer risk.

The negative effects of alcohol can impact your body long term. Here are some ways that regular heavy drinking can affect your physical health.

Excessive alcohol consumption is also a major factor in road and other accidents, violence, and crime. According to the National Drug Household Survey in 2019:

• About 1 in 5 alcohol drinkers aged 14 or older had put themselves or others at risk of injury or harm while drinking in the previous 12 months.
• Over 1 in 5 Australians aged 14 years or older had been a victim of an alcohol related incident in 2019. This included many types of abuse, including verbal or physical abuse.
• Adults aged 18-24 were more likely to binge drink than the rest of the population. Men were more likely to binge drink than women.

What is a hangover?

A hangover is the experience of unpleasant symptoms after drinking alcohol. Usually, the more you drink, the worse the hangover will be. Some people get a hangover after just one drink. Others may drink heavily and not experience a hangover at all. It depends on your body, and how it processes alcohol.

The symptoms of a hangover can include the following.

• Headache: Alcohol makes your blood vessels expand, which can lead to a headache.
• Dehydration: Alcohol is a diuretic (meaning it removes fluids from the body), so drinking excessively can lead to dehydration. It is the dehydration that causes many of the symptoms of a hangover, including thirst, dizziness, and light headedness.
• Feeling ill: Alcohol triggers the immune system to release chemicals that cause loss of appetite, and problems with concentration and memory.
• Nausea, vomiting and aching tummy: Alcohol irritates the lining of the stomach and increases the amount of acid in it.
• Shakiness: Alcohol can cause your blood sugar level to fall, which can make you weak, tired and shaky.
• Tiredness: Even though you may fall asleep when you drink, alcohol prevents the body from reaching the deeper stages of sleep. You may wake in the middle of the night after drinking heavily. You may even wake up and still have some alcohol in your system the next morning. This can delay the onset of a hangover until later that day. This means you may not be safe to drive or operate machinery.

Can you 'cure' a hangover?

Hangover cures are generally a myth. There are no cures for a hangover. All you can do is take steps to ease the symptoms and wait until it goes away.

• Drink water to treat dehydration. Don't drink any more alcohol — it will make you feel worse.
• Try to eat some simple food to boost your blood sugar and settle your stomach.
• Take pain relief if you have a headache or other pain.
• If you can, go back to bed to sleep through the hangover.

Tips to avoid a hangover

To avoid a hangover, don't drink more than you know your body can cope with. If you're not sure how much that is, be careful. Drink in moderation.

In Australia, alcoholic beverages are required by law to state the approximate number of standard drinks they contain on the label. This includes all bottles, cans, and casks.

Once you know how much alcohol a standard drink contains, you can keep track of what you're consuming. You may be surprised! A couple of glasses of wine can quickly add up to a lot more than you intended to drink.

To reduce your chances of getting a hangover:

• practice safe drinking by pacing yourself
• don’t drink on an empty stomach (eat before and during the drinking period)
• drink water while consuming alcohol, and before going to sleep

Resources and support

Drinkwise is an organisation established by the alcohol industry to encourage a healthier and safer drinking culture in Australia. To find out more about how alcohol affects your health, you can use the DrinkWise tool.

For trusted information about reducing the risk of alcohol use you can consult the NHMRC Alcohol Guidelines.