Pass Out Hard, Sleep Lightly

Alcohol makes you sleep heavily at first, then disrupts quality of sleep later in the night

(RxWiki News) For decades, researchers have known that alcohol can affect your quality of sleep. Now, a new study shows that the alcohol disrupts the quality of sleep in healthy women more than in healthy men.

According to lead author J. Todd Arnedt, assistant professor of psychiatry and neurology at the University of Michigan, a large portion of the population uses alcohol regularly to help deal with sleep problems. This is likely because alcohol initially causes sleepiness in the early part of the night. Later in the night, however, alcohol can heavily affect one's quality of sleep.

Arnedt and colleagues decided to explore the gender differences in the effects of alcohol on sleep because few past studies have had female participants. Because women metabolize alcohol different, the researchers believed it was important to study the effects of alcohol on sleep in women as well as men.

In a study that included 59 women and 34 men in their twenties, researchers monitored the intoxicated participants as they slept. Between 8:30 and 10:00 pm, the participants drank either a placebo or alcoholic beverage until they were intoxicated (specified by breath alcohol concentration). From 11:00 pm to 7:00 am, the researchers monitored the participants' sleep using polysomnography, a way of recording biophysiological changes during sleep. Before bedtime and upon awakening, the participants filled out questionnaires.

Among those who drank alcohol before sleep, women experienced greater levels of sleepiness and disrupted sleep quality compared to men. The study's findings also supported results from previous studies that showed that a high dose of alcohol causes a heavy sleep in the beginning of the night, but then leads to more wakefulness later in the night. A family history of alcoholism was not a factor that affected participants' sleep quality.

Arnedt points out that the differences observed between men and women are not a factor of women drinking more - the breath alcohol concentration of all participants was the same before going to sleep. Nor do the researchers believe that the differences were caused by differences in experience drinking alcohol because prior alcohol use was the same between both male and female participants.

Arnedt says the differences may be due to differences in alcohol metabolism.

He concludes that these findings may contribute to further research exploring the link between quality of sleep and the risk of developing alcohol use disorders.

According to the CDC, 61.2 percent of adults in the United States are current drinkers. Approximately 5 percent of adults are heavy drinkers.

The study by Arnedt and his colleagues will appear in the May 2011 issue of Alcoholism: Clinical & Experimental Research.

Review Date: 
February 16, 2011