A glass of wine in the evening feels like it helps you sleep. You drop off faster, you feel drowsy and relaxed. It seems like a good deal. It is one of the worst bargains in the whole of sleep.
The first half versus the second
Alcohol is a sedative, so it genuinely does help you fall asleep faster. That is the part you notice. What you do not notice is what happens later. As your body processes the alcohol, your sleep becomes fragmented and shallow in the second half of the night, and you spend less time in the restorative deep and dreaming stages.
This is why a few drinks can lead to waking at four or five, oddly alert, or to a night that felt long but left you flat. You traded a quick exit into sleep for a worse night overall.
Why you wake up tired
Alcohol also relaxes the airway, which can worsen snoring and breathing, and it is a diuretic, so it sends you to the bathroom. Add it up and the nightcap that felt soothing has quietly stolen the best part of your rest.
- Try to leave a few hours between your last drink and bed
- Match drinks with water to soften the effect
- Notice the difference on the nights you skip it entirely
The honest position
This is not a lecture about giving up. A drink with friends is one of life's pleasures and the odd late night will not undo you. The point is simply to stop believing the nightcap helps you sleep. It helps you fall asleep, and then quietly takes the rest back with interest.