If you're worried about your own or someone else's drinking, call the free alcohol helpline, Drinkline on 0300 123 1110

But what’s really going on in our brains and bodies when we’ve had a drink, and is there anything we can do to mitigate the effects of alcohol on our sleep? To find out what's happening biologically when you party hard and then XXWomen’s Health UK asked the experts.

So why does alcohol disrupt sleep?

Dr. Lindsay Browning, chartered psychologist, neuroscientist and member of the British Sleep Society (Trouble Sleeping) explains that while alcohol is a sedative and can therefore help with falling asleep, as the alcohol is metabolised it promotes wakefulness in the latter half of the night. This means that you’ll wake up more frequently in the early hours.

'Also,' she adds, 'alcohol affects the normal progression of the sleep stages we go through each night, meaning that the sleep we do get is not as restorative.'

NHS-trained sleep specialist, neuroscientist and founder of The Sleep Space, Dr Michelle Ní Raghallaigh, echoes this, telling WH: 'There’s a biological process that helps us sleep. This is a process where the longer we’re awake, the more pressure or drive there is to sleep.

'If you drink alcohol, it boosts this process in the first part of the night, but then that process wears off much more quickly, and then we wake up at 3 am!'

How does alcohol alter your sleep cycles?

Moreover, like Browning, she says: 'Alcohol affects both the deep sleep stages and the lighter REM sleep stages. It promotes deep sleep in the first half of the night, however, this occurs to the extent that it results in a compensatory reduction in this restorative type in the next half of the night.

Drinking alcohol will also impair REM or dream sleep in the first half of the night; this is then followed by a rebound of this lighter type of sleep in the second half of the night.'

Another way that alcohol affects sleep, both experts say, is that it is a sedative that relaxes the muscles in your airway, so if a person has any issues with snoring or sleep apnea, alcohol can worsen them, thereby worsening the quality of their sleep.

How do I stop alcohol from disrupting my sleep? 

Aside from forgoing your evening G&Ts? Dr. Browning says that, unfortunately, there’s not much getting around the inevitable hangover and the tiredness that comes with knocking back large amounts of booze.

'Alcohol at lower doses has less of a disruptive effect on sleep,' she says. 'You are less likely to wake up in the early hours and your sleep stages will be closer to normal the less you have drunk.' Find it hard to stagger your hard drinks? Intersperse each with an alcohol-free alternative, like fizzy kombucha, tonic water with a slice of lime in, or an alcohol-free beer.

Dr Ní Raghallaigh says the same. 'If you’re socialising late at night over the festive season and decide to have a drink, that’s okay – just know that it will disrupt your sleep that night or cause you to awaken feeling unrefreshed or more tired than usual. Accept it, move on, and just try to avoid or limit alcoholic drinks close to bedtime in your regular routine.'

She does recommend, however, leaving a 3-hour gap between your last drink and bedtime, as this may lessen the impact of the alcohol on your sleep.

Can wine give you insomnia?

Many people who drink alcohol and experience disruption to their sleep worry that it could cause a longer-term problem: insomnia. However, Dr Ní Raghallaigh explains that occasional drinking will not cause insomnia disorder by itself.

Plus, she says, if a person has insomnia, cutting out alcohol is unlikely to cure insomnia in the long term.

That doesn’t mean there isn’t a link between alcohol and long-term sleep issues worth keeping an eye on though, Dr Ní Raghallaigh warns.

'Sleep difficulty can be a driver of alcohol dependence, in that a person might start to drink in the evenings to help with falling asleep, with this leading to a vicious cycle of tolerance, worsening sleep, and alcohol dependence.'

Dr Browning agrees that 'many people with problems falling asleep use alcohol to help them fall asleep faster'. But because your body will develop a tolerance to the alcohol, what you drink won’t have the same effect of helping you to fall asleep.

If you, or someone you love, is using alcohol as a crutch for troubled sleep, get NHS support, or speak to your GP

'This can actually make falling asleep much harder without alcohol than it was originally,' she says. 'In essence, giving you insomnia. Since a third of people with insomnia report using alcohol to help them sleep, treatment for insomnia with talking therapy (Cognitive Behavioural Therapy for Insomnia) would be preferable.'

You can access free online CBT for sleep via Sleepio. You can also try online Acceptance and Commitment Therapy (ACT) via Sleep School.

How long does it take to sleep off alcohol?

This depends on how much you’ve drunk, says Dr. Browning. Generally speaking, she says the more you have drunk the longer it will take your body to metabolise it, so the more you have drunk the more disrupted your sleep will be.

Dr Ní Raghallaigh says: 'The half-life of alcohol is 4 to 5 hours, which means it takes that long to process half of the alcohol from the bloodstream. How long it takes for an individual to metabolise alcohol depends on lots of factors, including how much you’ve had to drink and its timing, as well as your individual metabolism, genetics, age, gender, body fat, ethnicity, medications, and whether there are any liver issues.

'Sleeping won’t speed up the processing of alcohol itself, but it should help you feel better!'.

Reference: Women's Health: Lauren Brown