Reviewing alcohol's effects on normal sleep

January 22nd, 2013 in Health /

Sleep is supported by natural cycles of activity in the brain and consists of two basic states: rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep. Typically, people begin the sleep cycle with NREM sleep followed by a very short period of REM sleep, then continue with more NREM sleep and more REM sleep, this 90 minute cycle continuing through the night. A review of all known scientific studies on the impact of drinking on nocturnal sleep has clarified that alcohol shortens the time it takes to fall asleep, increases deep sleep, and reduces REM sleep.

Results will be published in the April 2013 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

"This review has for the first time consolidated all the available literature on the immediate effects of on the sleep of healthy individuals," said Irshaad Ebrahim, medical director at The London Sleep Centre as well as corresponding author for the study.

"Certainly a mythology seems to have developed around the impact of on sleep," added Chris Idzikowski, director of the Edinburgh Sleep Centre. "It is a good time to review the research as the mythology seems to be flourishing more rapidly than the research itself. Also, our understanding of sleep has accelerated in the past 30 years, which has meant that some of the initial interpretations need to be revisited."

Some of the review's key themes are:

"One consequence of a delayed onset of the first REM sleep would be less restful sleep," said Idzikowski. "The first REM episode is often delayed in stressful environments. There is also a linkage with depression."

Ebrahim agreed. "One hypothesis is that alcohol acts like medications that are used for depression and anxiety," he added. "Studies on patients with depression have identified that untreated patients had excessive REM sleep, particularly in the early part of the night, and that antidepressant medication suppressed REM sleep. Alcohol acts like antidepressants, reducing REM sleep particularly in the first part of the night. This impact of alcohol on REM sleep may explain the mood elevation and anxiety reduction associated with alcohol use."

"This review really helps to clarify findings to date as they apply to normal individuals," said Idzikowski. "The high attrition rate from 153 to 20 published studies that were examined enables us to know the real state of play regarding the impact of alcohol on normal volunteers. Whilst some of the studies were rejected on methodological grounds, many were rejected because they were on physically or mentally disordered individuals."

Both Ebrahim and Idzikowski hope this review will help readers understand that short-term alcohol use only gives the impression of improving sleep, and it should not be used as a sleep aid.

"In sum," said Idzikowski, "alcohol on the whole is not useful for improving a whole night's sleep. 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 with alcohol."

Provided by Alcoholism: Clinical & Experimental Research

"Reviewing alcohol's effects on normal sleep." January 22nd, 2013. http://medicalxpress.com/news/2013-01-alcohol-effects.html