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The nightcap myth: why alcohol wrecks the sleep it seems to help
💡 Alcohol helps you fall asleep faster but suppresses REM and fragments the second half of the night, so the sleep it buys is shallower than it feels.
A glass of wine before bed feels like it works — you drift off faster. And you do: alcohol is a sedative, so it shortens the time it takes to fall asleep. But sedation is not the same as sleep, and the trade you're making shows up a few hours later.
As your body metabolizes the alcohol overnight, it triggers a rebound effect. The first half of the night gets suppressed REM sleep — the dreaming stage tied to emotional processing and memory — while the second half becomes fragmented and shallow, riddled with micro-awakenings you may not even remember. Alcohol also relaxes the muscles of your airway, worsening snoring and apnea, and its diuretic effect pulls you toward the bathroom.
The result is a night that looks long on paper but delivers little genuine recovery. You wake unrefreshed, having lost a chunk of the REM sleep that a normal night would have given you. Because the liver clears roughly one standard drink per hour, the fix is timing: finishing drinks at least 3–4 hours before bed lets most of the alcohol clear before you lie down, sparing the back half of your night.