The Real Dose-Response Between Alcohol and Your Sleep

Pooling 27 controlled studies of healthy adults, this review set out to answer a very specific question: how much alcohol does it actually take to disrupt sleep, and does more alcohol mean more disruption? The answer was a clear dose-response relationship. Even a low dose, roughly two standard drinks, was enough to delay the onset of REM sleep and shorten its overall duration, and both effects worsened progressively as the dose increased. It took a considerably higher dose, around five standard drinks, before alcohol also shortened the time it took to fall asleep and delayed deep sleep, but that apparent 'benefit' came at the cost of even greater REM disruption later on.

The authors were candid about the limits of the existing evidence: for total sleep time, sleep efficiency and total time spent awake during the night, results across studies varied too widely to draw firm conclusions. What the review does establish clearly is the core trade-off: alcohol's sedative effect and its cost to REM sleep move in the same direction, so there is no dose at which one arrives without the other.