Circadian variation of the acute and delayed response to alcohol: investigation of core body temperature variations in humans.

Very little research has been conducted on the interaction between alcohol and circadian rhythms, particularly using human subjects. This study focuses on humans' acute and delayed response to alcohol intoxication at different times of the day. The study, conducted over 8 weeks, was a within-subjects design with social drinkers consuming a dose of alcohol that would achieve a blood alcohol concentration (BAC) of 0.10 g/100 ml at either 1300 or 1800 h (or no beverage). Relative to the no-alcohol condition, the acute effect of drinking alcohol at 1300 h was a decrease in subjects' core body temperature, however, a similar effect was not evident after drinking alcohol at 1800 h. Moreover, irrespective of time of ingestion, alcohol consumption had an effect on core body temperature between 2330 and 0830 h. This delayed effect was ascribed to as a dampening of the core body temperature trough due to alcohol compared to the no-alcohol condition.