Feb. 15, 2011 -- Do you drink a nightcap to help you sleep? It may not be as effective as you think, new research suggests.
One of the largest studies to date on alcohol’s effects on sleep shows that drinking alcohol before bed may disrupt sleep and increase wakefulness in healthy adults -- affecting women more than men -- regardless of family history of alcoholism.
The research is reported in the May 2011 issue of Alcoholism: Clinical & Experimental Research.
In the women studied, alcohol decreased sleep duration and efficiency (ratio of time sleeping in bed to total time spent in bed) and increased how often they woke up during the night. Alcohol deepened sleep during the first half of the night but then disrupted sleep during the second half of the night, a finding that previous studies have reported.
Study researcher J. Todd Arnedt, assistant professor of psychiatry and neurology at the University of Michigan, says in a news release: “It’s clear that a substantial portion of the population uses alcohol on a regular basis to help with sleep problems. This perception may relate to the fact that alcohol helps people fall asleep quickly and they may be less aware of the disruptive effects of alcohol on sleep later in the night.”
The study included 93 healthy adults in their 20s (59 women and 34 men) who were college students or recent college graduates; 29 of the participants had a family history of alcoholism.
The study took place over two nights. On the first night, researchers randomly gave participants an alcoholic beverage containing either vodka or bourbon mixed with caffeine-free cola. On the second night participants were given a “placebo” beverage with a few drops of bourbon or vodka floated on top.
The researchers instructed them to drink to intoxication. After researchers measured their breath alcohol concentration (BrAC), participants slept for eight hours between 11 p.m. and 7 a.m.
The participants were monitored during their sleep. Participants completed questionnaires on sleepiness and sleep quality before bedtime and when awakened the next morning.