Alcohol is a false friend for people trying to get a good night’s sleep, especially when it’s consumed in excess.
It helps you fall asleep quickly and deepens sleep initially, but later on it disrupts sleep and causes middle-of-the-night wake ups. Overall, it produces unsettled sleep and alters sleep phases, including reduced REM sleep, the restorative phase when you dream and your memories are consolidated.
High doses of alcohol worsen sleep more in women, according to a study of 93 people in their twenties in the Boston area, published in Alcoholism: Clinical & Experimental Research. In the evening, participants drank to the point of intoxication, as determined by breath alcohol concentration, then were monitored throughout the night and questioned in the morning. Women reported that alcohol produced greater initial sleepiness. But objective measures showed that they ended up sleeping fewer hours than men and woke up more often and for longer periods.
It’s not surprising that there’s a gender effect at night, since women metabolize alcohol differently than men. The stomach enzyme that breaks down alcohol before it reaches the bloodstream is less active in women. This allows more alcohol to enter the blood.
Women also end up with higher blood alcohol levels because they tend to be smaller and have proportionately less body water than men (alcohol is diluted in body water). This study included only healthy young people who were self-described good sleepers. Alcohol’s effects on sleep may be worse in older people and those with sleep problems.
Bottom line: Don’t use alcohol to help you sleep.