A glass of wine at night – what it does to your sleep

A glass of wine with dinner, maybe another in front of the TV. You feel relaxed, fall asleep easily and think the evening did your sleep some good.

The first half of the night agrees. The second half doesn't.

What alcohol does to your sleep

Alcohol is a sedative. It dampens the nervous system, which is exactly why it helps you relax and fall asleep faster. In the first few hours, many people also sleep deeply – sometimes deeper than usual.

But your body breaks the alcohol down over the night, and as it leaves your blood, the effect flips. The nervous system, having been dampened, becomes easily roused instead. Sleep turns light and fragmented, you wake more often and find it harder to get back to sleep. That's why the night after a couple of glasses often starts well and ends with you lying there watching the clock.

Alcohol also affects REM sleep – dream sleep, where the brain processes impressions and emotions. It gets pushed back and shortened, especially when the amount of alcohol is larger.

On top of that come some more everyday effects: you need the bathroom, you snore more, and your body gets warmer. All of that disturbs sleep.

What the research shows

A review from the London Sleep Centre (Ebrahim et al., Alcoholism: Clinical and Experimental Research, 2013) went through studies in which healthy people were given alcohol before bed and then slept in a sleep laboratory, with brain activity and sleep stages recorded.

The pattern was clear: alcohol made participants fall asleep faster and sleep more deeply during the first part of the night. But during the second half, sleep got worse – more awakenings, more light sleep. REM sleep decreased, and the more alcohol, the clearer the effect.

In short: alcohol buys you a faster onset of sleep, and you pay for it later in the night.

What to do

This isn't about quitting. It's about knowing what you're trading away, and being able to choose.

1. Separate relaxation from sleep aid. If you want to enjoy a glass, do. But if you're drinking to sleep better, it's worth knowing it doesn't work that way.
2. Drink earlier in the evening. The more time your body gets to break the alcohol down before you go to bed, the less of the night is affected.
3. Keep the amount small. The effect on REM sleep grows with the amount. A glass with dinner is a different thing from a bottle.
4. Have alcohol-free evenings in the week. Not as a rule to feel guilty about, but as a way to notice the difference.

Try it yourself

Note in the app the evenings you drink, and how you slept. After a few weeks you'll see the pattern in black and white: how many times you woke, how you felt in the morning.

For many people it's that insight – not any ban – that moves the glass earlier in the evening, or a little more often turns it into a glass of water.