Alcohol and (the lack of) Sleep

Alcoholic beverages are well-known for their sleep-inducing properties - thanks to the anti-anxiety properties of alcohol which help suppress arousal and stimulation - and are commonly used as an over-the-counter somnogen (which is just a fancy word for sleep aid).

Indeed, low doses of alcohol at around 1 to 2 standard drinks (one standard drink equates to one can of beer, half a glass of wine, or one nip of hard liquor) may help us to fall asleep faster, reduce the incidents of awakening shortly after we fall asleep, and increase the amount of time we spend in rapid eye movement (REM) sleep – the stage of sleep when our eyes dart around under our eyelids in a rapid movement, as its name suggests; it is also the stage when our memory is consolidated, and which helps with concentration and learning.

However, there is more to the story.

At moderate doses (2 to 4 standard drinks), alcohol reduces the amount of brain-boosting REM sleep. Doesn’t sound like a good recipe for a good night’s sleep, does it?

At high doses (more than 4 standard drinks), it can have a rebound effect on the later stages of sleep, leading to longer periods of awakening while also decreasing the amount of REM sleep. Now that is really bad.

Furthermore, since alcohol is a diuretic, which means that it acts as a signal to your kidneys to expel more water from your body, the consumption of alcohol prior to sleep is usually associated with frequent late-night toilet trips and sleep disturbances. Losing the extra fluid would also leave you feeling dehydrated.

Consuming moderate to high amounts of alcohol before bed can also constrict the air passage, leading to episodes of apnea, whereby a person's breathing is interrupted during sleep. The risk is heightened in those who have a tendency to snore in their sleep.