It’s safe to say most people will have experienced a hangover at least once.

This is hardly surprising as, according to an Australian Bureau of Statistics survey, Australians drink 9.6 litres of pure alcohol a year.

Alcohol affects everyone differently. But if you have a hangover after a night out, you might have a headache, diarrhoea, nausea, a dry mouth and eyes, tiredness, increased heart rate, anxiety and trembling.

Can you really die from a hangover?

Professor Steve Allsop, of the Curtin University National Drug Research Institute, said drinkers won’t necessarily die from a hangover, but “excessive alcohol can cause an overdose”.

Alcohol is a depressant drug that slows down messages between the brain and the rest of the body.

A hangover can lead to reduced respiration, alcohol poisoning and  dehydration. Technically, any of these can cause death.

What effect does alcohol have on your body?

When a person drinks, alcohol is absorbed into the body through the stomach and small intestine.

“It absorbs very quickly and affects the brain and co-ordination,” Mr Allsop said.

Long-term alcohol exposure can shrink the brain’s frontal lobes, causing hallucinations and slurred speech. It can lead to cardiovascular disease, throat and mouth cancers, liver damage, lung infections and cause chronic pancreatitis.

Alcohol also has a diuretic effect, leading drinkers to urinate more often. That leads to dehydration.

It can also lead to malnutrition, as alcohol prevents minerals and vitamins from being absorbed into the body.

Can a hangover be prevented?

Dr Allsop said that there were numerous ways to prevent a hangover (apart from the obvious – not drinking too much in the first place).

“Make sure you don’t drink on an empty stomach, stay hydrated and have water before you go to sleep,” he said.

Tiredness is a key contributor to morning-after pain, so drinkers should get as much rest as they can, Dr Allsop said.

“It is also important to avoid things that might upset your stomach, like caffeine, so eat light, nutritious food. Think before you have that coffee,” he said.

“Essentially, a hangover is your body’s way of saying that you drank too much so don’t next time.”

How long does alcohol poisoning last?

A person’s blood alcohol level will continue to rise for half an hour after their last drink, as their liver processes the beverage.

“One standard drink metabolises in an hour,” Dr Allsop said. “This means 20 standard drinks would take 20 hours to metabolise.”

Why do some people tolerate alcohol better than others?

Size, weight, gender and overall health all affect the way someone tolerates alcohol.

“In general, men are bigger than women,” Dr Allsop said. “If an average man and an average woman had the same amount of drinks, the woman would have a higher blood alcohol reading.”

Dr Allsop also said that it is “not necessarily a good thing if you don’t get a hangover”, as this usually means you “don’t have an off-switch”.