Alcohol is the most common sleep aid in the world, and it does not work. It feels like it does, which is the whole problem: a couple of drinks make you drowsy and get you to sleep faster. Then, a few hours in, your body finishes metabolizing them and the rest of the night comes apart.
If you wear anything that reads your sleep, you have already seen it. If you take a morning scan, you have seen it there too.
What actually happens
For the first hour or two, alcohol is a sedative. Sleep comes quickly and the early part of the night is deep. Then it wears off, and the body, which has been suppressed, rebounds: heart rate climbs, the nervous system flips toward alert, and the second half of the night becomes light, fragmented and short on REM, the stage that does most of the work for memory and mood.
You may not wake fully. You will wake more often than usual, and you will wake earlier, and the sleep you did get did less for you than the hours suggest.
What it looks like in the record
Three things move, and they move together.
Overnight heart rate runs high, often five to ten beats above your normal, and stays there into the morning. Heart-rate variability drops, sometimes by a third, which is the nervous system’s alert half refusing to stand down. And the sleep stages, if your device reads them, show REM pushed late and cut short.
The morning face scan sees the first two directly. A reading after two glasses of wine at 10 pm looks a lot like a reading after five hours of sleep, and the morning insight will usually say so, because the check-in from the night before told it what you drank.
Timing is most of it
The dose matters, but the clock matters more. A drink at 6 with dinner is mostly gone by the time you are in bed. The same drink at 10 is being metabolized at 2 am, right when it does the most damage. Most of the effect on the night can be avoided by moving the last drink earlier rather than by removing it, and the record will show you exactly how much difference it made.
Water alongside helps a little, because part of what the morning shows is dehydration. Food helps, for the same reason. Neither fixes the timing.
Running your own experiment
This is one of the easiest things to test on yourself, because the effect is large and fast. Two weeks, logging what you drank and when in the evening check-in, and then reading the mornings back. Most people find they do not want to give it up so much as move it, and a few find that the Tuesday glass that felt harmless is costing them Wednesday.
Wave is for general wellness and is not a medical device. It does not diagnose or treat alcohol use disorders; anyone concerned about their drinking should talk to a doctor.
