Dr Michelle Ni Raghallaigh is an NHS-trained insomnia specialist and cognitive neuroscientist who works at Salus Wellness Clinics and she is author of this article.
Alcohol is a double-edged sword when it comes to our sleep; it can make us feel drowsy initially, but it tends to wake us up in the second half of the night. This is because alcohol is metabolized relatively quickly, so the sedative effect of alcohol wears off during the night, leading us to wake up or have lighter sleep. It therefore causes broken, fragmented sleep and disrupts the quality of our sleep.
There’s a biological process that helps us sleep; one where the longer we’re awake, the more sleep pressure or sleep drive we accumulate (a metabolic substrate known as adenosine) . If we drink alcohol, it boosts this process in the early part of the night, but then that process wears off much more quickly (Thakker et al.), and then we wake up at 3 am!
What about alcohol and the stages of our sleep? Alcohol affects deep sleep and also the lighter 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 important way that alcohol affects sleep is that it is a sedative that relaxes the muscles in your airway. Therefore, iIf you have any issues with snoring or sleep apnea, alcohol can worsen them, thereby worsening the quality of your sleep.
How can I stop alcohol from disrupting my sleep?
The good news though is that we don’t have to abstain from that lovely glass of wine in the evening altogether. A drink now and then, especially earlier rather than later in the evening, is absolutely fine (as long as you’re not using it as a sleep aid). The key thing to remember is to leave a 3-hour gap between your last drink and bedtime.
If you’re socializing 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.
Can alcohol give you insomnia?
While alcohol is a sleep disruptor, occasional drinking will not cause insomnia disorder by itself. If you have insomnia, cutting out alcohol is unlikely to cure insomnia in the long term. Ask yourself: do you have difficulty falling asleep or staying asleep for 30 minutes or more on 3 or more nights a week, for 3 months or longer? And is it affecting you in the daytime e.g. difficulty concentrating, low mood? If so, it may be that you’re experiencing chronic insomnia and it’s advisable to contact your GP and/or get in touch with a trained insomnia specialist for Cognitive Behavioural Therapy for Insomnia (CBTI), the ‘gold standard’ evidence-based treatment for insomnia.
In the case of alcohol dependence, however, the picture is more complex (Chakravorty et al., 2016). Many people develop tolerance to the sleep-promoting effects of alcohol rapidly. However, despite this, the rebound awakening in the second half of the night does not seem to be subject to tolerance effects i.e. the person will need higher and higher doses of alcohol to induce sleep, yet their sleep will still be disrupted, leading to the temptation then to ‘top up’ with another drink in the night. Sleep difficulty can be a driver of alcohol dependence i.e. starting to drink in the evenings to help with falling asleep, with this leading to a vicious cycle of tolerance, worsening sleep, and alcohol dependence.
How long does it take to sleep off alcohol?
The half-life of alcohol is 4 to 5 hours, which means it takes that long to process half of the alcohol in the bloodstream. How long it takes for an individual to metabolize 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!
Tip:
If you’re going to have a glass of wine or a cocktail or beer, have it before dinner or with dinner – but not after dinner!
An experiment:
If you drink something most nights and you’re unhappy with your sleep, try cutting it out for just one week and notice what happens with your sleep.
Links:
Cognitive Behavioural Therapy for Insomnia (CBTI) treatment:
https://www.thesleepsphere.com
Alcohol Support:
https://www.nhs.uk/live-well/alcohol-support/
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