Alcohol may help you fall asleep faster, but not so deeply
By David McNamee
A new review of available research has examined the effects of alcohol on sleep patterns.
The first study into the effects of alcohol and sleep was carried out in 1883, and its findings still seem to apply today. Those researchers found that when large doses of alcohol were provided, people slept much more soundly than normal to begin with, but they became more restless than normal later.
More recent studies have disagreed over how much of an effect alcohol has on REM sleep – or ‘rapid eye movement’ sleep – which makes up about 25 percent of a typical night’s sleep.
During REM sleep the brain is more active, and studies have shown that losing REM sleep can affect your memory, concentration, and movement. We also dream less without REM sleep.
As well as REM sleep, the new review looked at how alcohol affects ‘slow wave’ sleep, which we usually call ‘deep sleep’.
The new study suggests that only high doses of alcohol delay our ability to enter REM sleep – although scientists had previously thought that any amount of alcohol would have this effect. The alcohol increases the amount of deep sleep we get in the first half of the night. During that time, we fall asleep faster and sleep more soundly than normal.
Deep sleep is essential, because it is during deep sleep that the body repairs itself, building bone and muscle, and strengthening the immune system. However, when we are in an alcohol-induced deep sleep, we seem to be more likely to sleepwalk, snore, or have sleep apnoea (where your breathing repeatedly pauses while you are asleep). The study also confirms that you are more likely to wake up or sleep restlessly in the second half of sleep after drinking alcohol.
This was a big review, which examined all known scientific studies about how alcohol affects sleep patterns. So it is fairly likely to be reliable.
The study recommends that people don’t use alcohol to help them sleep. Although you may find it easier to fall asleep after drinking alcohol, your overall quality of sleep will be poorer, and you will be more likely to wake during the night.
Ebrahim IO, Shapiro CM, Williams AJ, et al. Alcohol and sleep I: effects on normal sleep. Alcoholism: Clinical and Experimental Research.