Think a nightcap may help you get a better night’s sleep? Think again.  

A new review of 27 studies shows that alcohol does not improve sleep quality. According to the findings, alcohol does allow healthy people to fall asleep quicker and sleep more deeply for a while, but it reduces rapid eye movement (REM) sleep. And the more you drink before bed, the more pronounced these effects.

REM sleep happens about 90 minutes after we fall asleep. It's the stage of sleep when people dream, and it's thought to be restorative. Disruptions in REM sleep may cause daytime drowsiness, poor concentration, and rob you of needed ZZZs.

“Alcohol may seem to be helping you to sleep, as it helps induce sleep, but overall it is more disruptive to sleep, particularly in the second half of the night,” says researcher Irshaad Ebrahim. He is the medical director at The London Sleep Centre in the U.K. “Alcohol also suppresses breathing and can precipitate sleep apnea,” or pauses in breathing that happen throughout the night.

The more a person drinks before bed, the stronger the disruption. One to two standard drinks seem to have minimal effects on sleep, Ebrahim says. Alcohol Is Not a Sleep Aid “The immediate and short-term impact of alcohol is to reduce the time it takes to fall asleep, and this effect on the first half of sleep may be partly the reason some people with insomnia use alcohol as a sleep aid,” Ebrahim says.

“However, this is offset by having more disrupted sleep in the second half of the night.”

“Alcohol should not be used as a sleep aid, and regular use of alcohol as a sleep aid may result in alcohol dependence,” he says. The findings will appear in the April 2013 issue of Alcoholism: Clinical & Experimental Research.

Alcohol tricks people into thinking they are getting better sleep, says Scott Krakower, DO. He is an addiction specialist at North Shore-LIJ in Mineola, N.Y.

“People who drink alcohol often think their sleep is improved, but it is not.” REM is the more mentally restorative type of sleep, says Michael Breus, PhD, a sleep specialist in Scottsdale, Ariz.

“Alcohol is not an appropriate sleep aid. If you rely on alcohol to fall asleep, recognize that you have a greater likelihood to sleepwalk, sleep talk, and have problems with your memory.”

If you are having trouble sleeping, talk to your doctor about how to improve your sleep quality. He or she may be able to rule out underlying sleep disorders like sleep apnea and suggest appropriate sleep aids. Better sleep habits can also help. Some tips to improve sleep habits include:

• Get regular exercise, but no later than a few hours before bed.
• Avoid caffeine, alcohol, or nicotine in the evening.
• Reserve the bed for sleeping and sex only.
• Keep your bedroom at a cool temperature.
• Set regular wake and bed times.

  SOURCES:Ebrahim, I. Alcoholism: Clinical and Experimental Research, 2012, study received ahead of print.Irshaad Ebrahim, medical director,The London Sleep Centre in London, U.K.Michael Breus, PhD, sleep specialist, Scottsdale, Ariz.Scott Krakower, DO, addiction specialist, North Shore-LIJ, Mineola, N.Y. © 2013 WebMD, LLC. All rights reserved.