Alcohol

What is the connection between alcohol and sleep? A common myth is that alcohol is helpful for sleep because it can make you feel sleepy. Research does not support this widely held belief. In fact, alcohol can disrupt the deep sleep that your body needs, leaving you tired the next day. Alcohol depresses or “turns off” brain regions it encounters.

Falling asleep and initial sleep:

Short term, occasional alcohol use depresses wakefulness, which may promote falling asleep more quickly and staying in a deeper sleep during the first half of sleep.
But, regular and heavier alcohol use (women: 4 or more per occasion; men: 5 or more per occasion) can bring tolerance to this effect in as little as 3 days, after which alcohol no longer quickly induces sleep.

Staying asleep:

Though short-term, moderate alcohol use may have some sleep-promoting effects during the first half of sleep, any alcohol use within 6 hours of sleep can negatively impact the second half of sleep.
Just like alcohol consumption depresses the brain, alcohol elimination stimulates the brain. Remember, your body produces a compensatory response to bring you back to your baseline. Since alcohol increases sleepiness, your body brings you back into balance by increasing alertness. This effect causes more awakenings and reduces your total N3 sleep time (i.e. the deep, slow wave sleep, that may be the most restorative).
If one of these awakenings occurs in the morning at the time you usually get up, it can be difficult to go back to sleep despite being tired.
Alcohol’s effects on the second half of sleep worsen with heavier alcohol use.

Over a couple of nights, alcohol can greatly decrease your total sleep quantity and result in increased tiredness and sleep deprivation.

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