Drinking alcohol may help a person fall asleep, and increase deep sleep during the first half of the night, but can disrupt sleep during the second half, a new study finds.
Researchers reviewed 20 previously published studies on alcohol and sleep, according to NBCNews.com. They found alcohol reduced the time it takes people to fall asleep, and helped them to sleep more deeply during the first half of the night, no matter how much they consumed.
During the second half of the night, sleep disruption, or waking after falling asleep, increased. Having at least two drinks reduced overall rapid eye movement (REM) sleep. Dreaming occurs during REM sleep, and is thought to be important for memory, the article notes.
The study included people who were healthy, and who were tested in an overnight sleep lab. It will be published in the journal Alcoholism: Clinical and Experimental Research.
“Alcohol on the whole is not useful for improving a whole night’s sleep,” study co-author Chris Idzikowski, Director of the Edinburgh Sleep Centre, said in a news release. “Sleep may be deeper to start with, but then becomes disrupted. Additionally, that deeper sleep will probably promote snoring and poorer breathing. So, one shouldn’t expect better sleep with alcohol.”