Bedtime alcohol altered sleep patterns
An experiment by American scientists showed that sleep changes persisted for several nights if a person drank an alcoholic beverage each time before going to bed. Consequently, sleep did not adapt.
A glass of wine before bed after an exhausting day at work is a familiar ritual for many modern people, including those who have trouble falling asleep. However, a study by neuroscientists from Brown University and the Sleep Laboratory at EP Bradley Hospital in Providence (USA) has shown that drinking alcohol at bedtime significantly affects sleep patterns due to a reduction in the rapid eye movement (REM, rapid eye movement) phase. A paper with the results is published in the journal Sleep.
The authors of earlier studies also concluded that alcohol consumption, although it reduces the latency period of falling asleep, has a bad effect on the quality of sleep. Nevertheless, its effect on the structure of nighttime rest is still poorly understood. For example, the "cumulative effect" if a person drinks several nights in a row remained in question.
To deal with this, American scientists conducted an experiment. It involved 30 adults (15 men and 15 women) from 31 to 47 years old. For three nights, they slept eight hours each in the lab while researchers monitored their brain activity. The test was repeated twice for each subject (three nights apart), but with different drinks. The participants were given a non-alcoholic or alcoholic cocktail 45 minutes before bedtime. The lights were turned off 15 minutes after the person went to bed.
To analyze the data, scientists used linear mixed-effects models and generalized additive models. In the end, they found that alcohol shortened the rapid eye movement phase of sleep (REM phase) and increased the duration of slow-wave sleep (Slow-wave sleep). The body did not adapt to the effects of alcohol: the changes were the same with repeated use as if it were the first time.
Although the participants could fall asleep faster after drinking alcohol, the quality of their sleep deteriorated: it is during the REM-phase, which takes 25-30 percent of the entire sleep period, a person sees vivid dreams, he forms key cognitive skills, the brain processes the emotions experienced during the day and organizes information. Plus, the REM phase of sleep activates the central nervous system and helps prepare for waking up.
"Our data showed that alcohol consumption before bedtime significantly affects sleep patterns, including changes in the slow-wave and REM phases of sleep. <...> Consequently, the use of alcohol as a sleeping aid remains a public health concern," the authors of the article concluded.