Sleep researchers analyzed 20 previously published studies on the effects of alcohol on sleep. The studies included more than 500 healthy people who drank low, moderate or high amounts of alcohol before undergoing testing as they slumbered in a sleep lab, reported NBC News.
What the researchers found was that drinking alcohol right before bedtime disrupts the normal sleep cycle. Although people may nod off more quickly and reach deep sleep during the first part of the night, they then often wake during the second half of the night.
In addition, alcohol shortens the sleep cycle during which we dream, and it affects breathing so that even non-snorers begin to snore. Those who already snore suffer sleep apnea, when breathing is interrupted, researchers with The London Sleep Centre told the BBC.
The fact that alcohol causes us to fall into deep sleep more quickly may sound like a benefit, but it also reduces the time we spend in the stage of sleep where we dream, called rapid eye movement, or REM, sleep. As a consequence, the sleep may feel less restful, said lead researcher Irshaad Ebrahim, medical director of The London Sleep Centre. Lack of REM sleep – which typically accounts for 20 to 25 percent of our sleep – can also have a detrimental effect on concentration, motor skills and memory, Ebrahim and his team said.
“We should be very cautious about drinking [before bedtime] on a regular basis,” Ebrahim told the BBC. “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.”
The research will be published in the April issue of Alcoholism: Clinical & Experimental Research.
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“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.”