Alcohol reduces how much time we spend in rapid eye movement (REM) sleep - the stage of sleep where dreams generally occur.

BBC: Alcohol-fuelled sleep 'less satisfying'

During a sleep study, wires attached to the head monitor brain waves that reveal which stage of sleep a person is in.

WSJ: More Children With Sleep Problems Seek Overnight Tests

Excessive alcohol consumption disrupts the 'REM' (Rapid Eye Movement) stage of deep sleep to ruin a night's rest, according to the UK Department of Health.

CNN: Vital Signs health tips

Her friend Brianna was allowed to sleep over, and they used their Bratz dolls to stage fashion shows.

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