Many people turn to a glass of wine or two to help them relax before bed, as drinking alcohol in moderation has a sedative effect at first. However, as the night goes on, this effect wears off.
"While it can maybe help people fall asleep, it disturbs sleep—especially in the second part of the night. It's not an effective sleep aid to turn to," Fiona Baker, Ph.D., the Director of the Human Sleep Research Program at SRI International, says of alcohol.
That's because as alcohol gets metabolized in the night, it disrupts essential deep sleep stages like REM sleep. Baker adds that it can also increase body temperature and heart rate, cause inadequate hydration, and lead us to need to use the bathroom—all things that will further disrupt sleep quality.
"Although alcohol makes you sleepy and might help you fall asleep, the sleep you're getting is worse," says sleep doctor Daniel I. Rifkin, M.D. This fragmented sleep is one of the reasons you might wake up feeling tired and groggy after a night of drinking—despite spending the same amount of time in bed as usual.