Having a drink before bedtime may help you fall asleep faster, but experts warn that it isn’t offering any incentives on the quality of sleep time.
Researchers from the London Sleep Centre have reviewed the evidence of having a tipple before bedtime to see what effect it has on nighttime slumber. The evidence gathered indicates that alcohol upsets our normal sleep cycle, and effectively disrupts our most satisfying type of sleep: REM sleep. REM sleep (rapid eye movement sleep) is the phase of sleep in which our dreams occur. Overall sleep is supported by natural transitions from REM sleep and non-REM (NREM) sleep. Typically, people begin the night sleep cycle in the NREM phase followed by a short period of REM sleep. The phases switch back and forth over 90-minute cycles throughout the night.
While alcohol may shorten the amount of time it takes to fall asleep, the experts say it increases deep sleep and reduces, or in some cases, removes REM sleep. They also suggest that using alcohol too often can disrupt not only the quality of sleep, but sleep period—causing insomnia. Results of the review will be published in the April 2013 issue of Alcoholism: Clinical & Experimental Research. The paper is also available for Early View.
“This review has for the first time consolidated all the available literature on the immediate effects of alcohol on the sleep of healthy individuals,” said Irshaad Ebrahim, medical director at The London Sleep Centre as well as corresponding author for the study. Lack of a good night’s sleep can have a detrimental effect on concentration, motor skills and memory. Ebrahim said he hopes this review will help people understand that even short-term use of alcohol does not improve the quality of sleep, as has been widely believed, and should refrain from using it as a sleep aid. “Alcohol on the whole is not useful for improving a whole night’s sleep,” added Chris Idzikowski, of the Edinburgh Sleep Centre, a colleague of Ebrahim. “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.”
The review found that alcohol consumption, at all dosages, brings on sleep quicker, leading to deeper sleep in the first half of sleep, but leads to an increase in sleep disruption during the second half of sleep; and the higher the dosage, the greater the impact on sleep quality. Ebrahim noted that the issue is not just a problem at the home level, but reaches far and wide. Both nursing homes and hospital wards have been known to serve alcohol to patients to help them get to sleep faster, many on a nightly basis.
“We should be very cautious about drinking on a regular basis,” said Ebrahim in a statement to the BBC. “One or two glasses might be nice in the short term, but if you continue to use a tipple before bedtime it can cause significant problems.” “If you do have a drink, it’s best to leave an hour and a half to two hours before going to bed so the alcohol is already wearing off,” he added. He noted that people could become dependent on alcohol for sleep. And eventually, this type of behavior could lead to more sleep disruptions, snoring and even sleep apnea.
In a review of more than 100 sleep studies, 20 were analyzed in detail and Ebrahim and his colleagues found alcohol appeared to change sleep in three ways: sleep acceleration, deep sleep, and sleep fragmentation. The first two are identical to symptoms seen in antidepressant users, and also may explain why some people with insomnia use alcohol. As these people awake in the morning, they may find that they feel less restful and often dehydrated, said Ebrahim. “This review really helps to clarify findings to date as they apply to normal individuals,” said Idzikowski. “Whilst some of the studies [we reviewed] were rejected on methodological grounds, many were rejected because they were on physically or mentally disordered individuals.” “In sum, alcohol on the whole is not useful for improving a whole night’s sleep,” concluded Idzikowski.