How alcohol affects your sleep

As many of us know, alcohol can affect many aspects of our health. But did you know that it can have a negative effect on our sleep? Alcohol disrupts the sleep/wake cycle (our internal 24-hour clock) and suppresses melatonin which regulates the sleep cycle.

Alcohol is a sedative…

People often say that alcohol can help get you to sleep and yes, this is true but with some caveats that are perhaps less discussed.


The sedative effects wear off, and in the second part of the night as the body reacts to the effects of alcohol, sleep quality is reduced. This is mainly due to the effects on Rapid Eye Movement (REM) sleep. REM sleep is generally acknowledged to be the “restorative” component of sleep, so a lack of REM sleep can reduce concentration and focus the next day. A study conducted in pilots found that alcohol consumed before bedtime, in a quantity sufficient to be “legally intoxicated”, led to impaired performance 14 hours later.

What often happens is that the amount of REM sleep in the first part of the night is reduced, and then in the second part of the night there is a rebound effect as the body tries to adapt. So, the normal sleep cycle is disrupted. When you combine this with the fact that alcohol’s diuretic effect results in more trips to the bathroom during the night, it’s not surprising that alcohol intake leads to feeling of tiredness the next day.


Binge drinking is particularly associated with sleep problems, with a study in young people in US showing that increased frequency of binge drinking has the largest impact. With 20% of Irish drinkers binge drinking at least once a week, this impact may be more prevalent in our society than we realise. Binge drinking is when you consume six or more standard drinks at one time. This can lead you to feel tired the next day, no matter how much time you spend in bed.  You can reduce the likelihood of alcohol causing sleep problems by avoiding binge drinking or by cutting out alcohol altogether. These other tips may help you get a good quality sleep.

    • Avoid alcohol and caffeine close to bedtime
    • Make sure your bedroom is cool and comfortable
    • Make a list of things to do the next day, so that you don’t spend time worrying
    • Avoid electronics in the bedroom

The HSE low-risk weekly guidelines are that women should drink no more than 11 standard drinks per week, and men no more than 17 standard drinks. A standard drink is 100mls of 12.5% wine, half pint of beer/lager/cider or 35.5mls (pub measure) of spirits.