Conventional wisdom has it that if you need a good night’s sleep a little nightcap will send you on your way to dreamland. But a 2012 review of 27 studies shows that alcohol allows healthy people to fall asleep faster and sleep more deeply for a while, but it reduces rapid eye movement (REM) sleep. And the more you drink, the greater these effects.
REM is the most restorative part of your sleep. When it’s disrupted, the results include daytime drowsiness, and poor concentration.
Here are four other ways that alcohol can disturb your sleep:
1. It’ll wake you up with the sparrows. During the first part of the night you’ll pass out, but the second half will be restless and you might find yourself wide awake at 4am, or earlier.
2. You’re more likely to snore … or worse. Alcohol is a muscle relaxant and can exacerbate sleep apnoea – a breathing disorder that sees the throat and airway muscles collapsing during sleep.
3. You’ll need more bathroom breaks. Alcohol is a potent diuretic, so be prepared to be up all night urinating.
4. It increases your chances of sleep-walking. And who knows what you might do while you’re wandering around? Sleep-walking is a type of parasomnia, one of many types of abnormal sleep behaviour.
So what, now what? We’re not saying don’t drink at night – just don’t expect alcohol to help you sleep. A small, occasional drink before bedtime is one thing, but even a moderate intake of alcohol can really mess with your sleep. One or two drinks a day should be the most you drink, and you need to stop at least an hour before bedtime.
Ebrahim, I. Alcoholism: Clinical and Experimental Research, 2012