Page last updated: Tuesday, November 18, 2008
Alcohol and Sleep
by Dr. Erik Skovensborg
Sleep is not what it used to be. We live in a world where something is going on around the clock and compared to the good old days 100 years ago we spend 25% less time in the arms of Morpheus in the 21st century.

Stress and worries are the cause of poor sleep in many people; however, some of our recreational drugs may also play a role (BMJ 1993;306:573-75). Caffeine has a long half life (five hours) and drinking more than six cups of coffee a day is likely to cause an increased number of disturbances during the night as well as insomnia. Neither are cigarettes a boon to sleep; the average smoker sleeps about 30 minutes less than a non-smoker.

How about a nightcap?

Alcohol is a well-known sedative; a glass of wine, a beer or a toddy has been used as a hypnotic for centuries. The effects of alcohol as a nightcap are a mixture of the good, the bad and the ugly. One of the reasons for the popularity of the nightcap is that the good effects of a drink are the ones to appear first (J Stud Alcohol 1982;43:434-44):

In short, alcohol reduces sleep latency from 28 to 12 minutes i.e. a drink makes you doze off faster. A drink will also increase slow wave sleep during the first part of the night and the deep stage 3-4 sleep, tired nature’s sweet restorer of body and brain.

According to an Egyptian proverb, one of the worst experiences in life is "to be in bed and sleep not", and since medieval times beer has enjoyed a reputation as a drink with special somnifacient qualities due to its contents of hops. Hops are believed to have a sedative effect on the nervous system. Forty years ago personal experience and the results of an experiments with 50 elderly persons (who on interrogation were found to have difficulties with sleeping) led a New York physician to praise the value of stout as a sedative and relaxing sopoforic (Journ Am.GeriatricSoc.1963;11:238-41). The recommended dose of stout was one bottle (342 ml); one-sixth of the amount required to produce an intoxicating level of alcohol in the blood.

No rose without a thorn

O little town of Bethlehem,

How still we see thee lie!

Above thy deep and dreamless sleep

The silent stars go by.

(Phillips Brooks)

In the world of the American poet Phillips Brooks a deep and dreamless sleep was the best sleep possible, however, the vivid dreams of rapid eye movement (REM) sleep act as a refreshing bath on the mind keeping us easy-going and good-tempered. Under normal conditions approximately 25% of total accumulated sleep is spent in REM sleep, however.

Alcohol does affect REM and so we can pay the price of our nightcap. Alcohol can reduce the amount of REM sleep during the first half of the night. Secondly, when blood alcohol concentrations fall to near zero later in the night there are an increased number of wakings as well as an increase in the amount of REM sleep.

The rebound phenomenon may be quite pronounced in some people, especially with larger doses of alcohol (more than 1-2 drinks at bedtime); the result may be complaints of recurrent awakening with tachycardia, sweating, headaches, and intense dream recalls or nightmares from around 3 a.m. and onwards. Sleepers tend to awake during the REM phases of this period when they otherwise would not and find difficulty in returning to sleep thereafter.

The ugly part

If the quantity of alcohol consumed as a nightcap is increased, the benefit of reduced sleep latency disappears but the disruptive effect found in the second half of the sleep increases markedly: more frequent awakenings, worse sleep quality, reduction of deep sleep, and earlier-than-usual waking times. An alcoholic experiences similar, but more severe, types of sleep disruptions. Sleep problems have also long been known to become more common as we grow older. A recent study of 139 alcohol-dependent patients found that the adverse effects of age and alcohol dependency on sleep quality were addictive (J Stud Alcohol 2001;62:335-43).

A study in the August 2003 issue of Alcoholism: Clinical and Experimental Research has found that alcoholics can continue to have sleep problems for many months after they quit drinking.

"They take a long time to fall asleep, have problems sleeping through the night, and feel their sleep is not restorative," said Shawn R. Currie, assistant professor of psychiatry and psychology at the University of Calgary and correspondent author for the study. "Overnight-sleep studies have documented reductions in deep sleep and abnormalities in REM sleep in alcoholics with more than a year of sobriety."

O gentle sleep

O sleep O gentle sleep!

Nature’s soft nurse, how have I frightened thee,

That thou no more wilt weigh mine eyelids down

And Steep my senses into forgetfulness? (Shakespeare, Henry IV)

The best chance of a gentle sleep lies in good sleep hygiene (JAMA 1999;281:991-99):

1. Go to bed only when sleepy

2. Use the bed and bedroom only for sleep and sex

3. Get out of bed and go to another room when unable to fall asleep within 15-20 minutes

4. Repeat this step as often as necessary

5. Arise at the same time every morning regardless of the amount of sleep obtained the previous night

6. Refrain from stimulants like caffeine in the evening

Regarding the famous nightcap you have to recognize the virtues and vices of alcohol. An occasional beer or glass of port before bed may well serve as a relaxing sedative for the normal person with temporary difficulties with sleeping. However, the dire consequences of deviating from the straight and narrow path of an occasional nightcap call for a warning against developing the habit of a drink or two to help to go to sleep - it won’t help. Better to enjoy your drink of preference with your meal earlier in the evening.

Erik Skovenborg is a General Practitioner and a founder member of the Scandanavian Medical Alcohol Board. He is a valued member of the AIM Social, Scientific and Medical Council.

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All text and images © 2003 Alcohol In Moderation.