From work parties to family gatherings and catching up with pals in the pub, the festive season is full of opportunities to indulge in a flute of fizz, a glass of mulled wine, or any other boozy beverage of choice.

If you’re not careful, before you know it you’re cranking up the Christmas tunes, doing your best Mariah Carey impression, and feeling very merry indeed.

Many of us know what it feels like to wake up with a sore head after one too many yuletide tipples, but have you ever wondered what being intoxicated actually does to your body?

Experts talk through some of the physical and mental effects of overindulging in alcohol…

Health risks

“Even though some types of alcoholic beverages, such as red wine, contain antioxidants, the negative impact of alcohol outweighs its positive effects,” says Lifesum nutritionist Signe Svanfeldt.

While it’s nice to enjoy a festive tipple if you fancy it – the NHS in the UK recommends no more than 14 units of alcohol a week, spread across three days or more – there are plenty of drawbacks in terms of your health. Speak to your GP if you have any concerns about your drinking, or seek advice from charities like Drinkaware.

“Drinking an excessive amount of alcohol increases the risk of cancer and cardiovascular diseases,” says Steph Keenan, operations manager at alcohol and mental health charity With You. “Alcohol can also raise our blood pressure, and be harmful to all organs in our body, including the stomach and liver.”

Excessive drinking is damaging to the liver in two big ways, the first being a type of scarring called cirrhosis.

“Scar tissue builds up because alcohol changes the chemicals that break down and remove scar tissue,” says Rob Hobson, head of nutrition at Healthspan. “Over time, this means scar tissue replaces healthy cells and the liver struggles to work properly.”

Alcohol can cause a build-up of fat in the organ: “Fatty liver disease can stop it from working properly. This is reversible in the first instance, by stopping alcohol consumption for [at least] two weeks.”

The calorific nature of alcohol means that “the body also uses this as an energy source while fat is stored”, Hobson continues. “Drinking excessively can lead to weight gain – and for men especially this gathers around the belly, which is a risk factor for cardiovascular disease.”

As well as the direct impact, drinking to the point of intoxication can contribute to other health issues, with Keenan saying: “It also increases the risk of injuries and contagious diseases, especially respiratory diseases.”

Brain activity

While knocking back drinks might bring feelings of euphoria and an initial burst of energy, it’s a different story in your grey matter.

“Drinking alcohol affects our central nervous system and slows down brain activity,” says Svanfeldt. “It can also affect our memory and self-control.”

That’s why some people engage in more risky behaviour while drunk – or perhaps they fall over, and can’t remember how they got those bruises the next morning.

Sleep problems

“If you have trouble sleeping, alcohol might seem to help in the short term, as it can make you feel more relaxed,” says Keenan. “But regularly drinking alcohol can make sleep problems worse.”

And even if you’re conked out after a few bevvies, the sleep you’re getting isn’t as good. “Alcohol can impair the restorative part of the sleep cycle, REM, as well as interfering with the flow of calcium into nerve cells, affecting the region of the brain that controls sleep function,” says Hobson.

You may find yourself waking up more frequently, too: “Alcohol causes dehydration – it inhibits the anti-diuretic hormone (ADH) causing you to use the bathroom more regularly,” Hobson adds.

Emotional effects

While having a couple of drinks can cause a spike of dopamine, which induces the ‘happy-drunk’ feeling, in the long-run alcohol can act as a depressant.

“Regularly drinking alcohol affects your brain chemistry in a way that can lead to feelings of depression,” Keenan explains, which can create a damaging cycle. “People may drink alcohol because they feel depressed, but heavy use depresses their mood further, which leads to more drinking, and so on.”