Does alcohol affect your sleep? What research says, and what your own data can show

What research reports

A review of the laboratory studies on healthy people (Ebrahim and colleagues, 2013) found that alcohol tends to shorten the time it takes to fall asleep, and that deep sleep can increase in the first half of the night. It also found that alcohol reduces REM sleep, especially at higher doses, and that sleep tends to be more broken in the second half of the night. The authors concluded that alcohol isn’t a good sleep aid.

Studies outside the laboratory point the same general way. One observational study of about 4,000 Finnish employees looked at overnight heart-rate recordings on nights with and without alcohol, to see how drinking related to the body’s overnight recovery.

Why averages aren’t enough

Those results describe groups of people. How much a drink changes your own sleep or overnight recovery depends on you, the amount, the timing, and what else is going on that day. Two people can drink the same amount and see different results.

How to see what it does for you

The Gap does this comparison for you: you log alcohol in the daily check-in, and it tests whether nights after drinking differ from other nights in your own sleep and HRV, adjusting for other factors and for chance. It reports a finding only when the pattern holds up, and labels it early or confirmed.

This is general information, not advice about whether or how much to drink. If you’re concerned about your drinking, free confidential support is available (in Australia, the National Alcohol and Other Drug Hotline is 1800 250 015), and your doctor can help.

• Record your drinks (and when) alongside your sleep and recovery readings for several weeks.
• Compare nights with and without alcohol, keeping in mind that other things differ too: a night out often means a later bedtime, a big meal and a different day.
• Look for a pattern that repeats across many nights, not a single bad night.