Your nightcap could be doing more harm than good, new research reveals. Though we often refuse to believe it, researchers have known for decades that alcohol can initially deepen sleep during the early part of the night but then disrupt sleep during the latter part of the night; this is called a “rebound effect.” A new study has found that intoxication can increase feelings of sleepiness while at the same time disrupt actual sleep measures in healthy women, more so than in healthy men.
“It’s clear that a substantial portion of the population uses alcohol on a regular basis to help with sleep problems,” said J. Todd Arnedt, assistant professor of psychiatry and neurology at the University of Michigan and lead author of the stud, which will be published in the May 2011 issue of Alcoholism: Clinical & Experimental Researchy. “This perception may relate to the fact that alcohol helps people fall asleep quickly and they may be less aware of the disruptive effects of alcohol on sleep later in the night.”
In the study, reveals Arnedt, “Alcohol increased self-reported sleepiness and disrupted sleep quality more in women than men. Morning ratings of sleep quality were worse following alcohol than placebo. Findings also confirmed results from other studies that a high dose of alcohol solidifies sleep in the first half of the night, meaning more deep sleep, but disrupts it in the second part of the night, meaning more wakefulness.”
With respect to gender differences, women objectively had fewer hours of sleep, woke more frequently and for more minutes during the night, and had more disrupted sleep than men.
“These differences may be related to differences in alcohol metabolism,” explained Arnedt, “since women show a more rapid decline in BrAC following alcohol consumption than men.”
The takeaway? Have your glass of wine with dinner and you’ll have a more restful night’s sleep—the whole night!