Sleep and low doses of alcohol.

The effect of 3 doses of alcohol (0.16, 0.32 and 0.64 g/kg) on sleep was studied in 6 healthy young adults. Total sleep time was increased and awake activity was reduced by 0.16 g/kg. The sleep efficiency index was improved by 0.16 and 0.32 g/kg. All 3 doses reduced slow wave sleep, and this was related to the latter part of the night. There was some evidence that REM sleep was delayed, and the REM/NREM ratio reduced. Low doses of alcohol may partially improve sleep, but there are reductions in slow wave activity, and disturbances in REM sleep are likely above 0.32 g/kg.