Those nightcaps might affect your sleep more than you thought -- and not in a good way.
A new review of studies, published in the journal Alcoholism: Clinical & Experimental Research, shows that alcohol changes the normal rhythms of sleep by increasing the amount of time people spend in "deep sleep," but also decreasing the amount of time people spend in REM sleep by disrupting sleep during this stage, which is necessary for memory, concentration and motor skills.
"In sum, alcohol on the whole is not useful for improving a whole night's sleep," study researcher Chris Idzikowski, who is the director of the Edinburgh Sleep Centre, said in a statement. "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."
Sleep has two parts that cycle back and forth: non-REM sleep, and REM sleep. The cycle takes 90 minutes, and continues on through the night -- it starts with non-REM sleep, and then goes on to REM sleep, and then back to non-REM sleep, and so on and so forth.