Sleep and circadian influences on blood alcohol concentration

Anecdotally, adults reach higher levels of subjective intoxication on days they are fatigued or sleep deprived; but sleep is not discussed as a predictor of blood alcohol concentration (BAC) in clinical settings. To inform clinical work and future research, an analysis examined the impact of sleep and circadian factors on indicators of BAC in humans and animal models. Literature searches of medical and psychological databases were conducted to identify articles that manipulated sleep/circadian factors and reported effects on indicators of alcohol pharmacology (e.g., BAC, alcohol metabolism). 21 studies met inclusion criteria.
Studies included manipulations of time of day, circadian phase and time in bed. Evidence for time-of-day effects on alcohol pharmacology was most compelling. Studies also provided evidence for circadian phase effects, but failed to find support for time-in-bed effects. Although results were not uniform across studies, most evidence from human and animal models indicates that peak BACs occur toward the beginning of the biological day, with some studies indicating slower alcohol elimination rates at this time.
Circadian factors likely influence alcohol pharmacokinetics, perhaps due to altered elimination of alcohol from the body. This means that individuals may reach higher BACs if they drink during the morning (when, for most people, circadian alerting is low) vs other times of day. Alcohol prevention and intervention efforts should highlight sleep/circadian health as a potential contributor to alcohol-related harm.
Source: Miller MB, Cofresí RU, McCarthy DM, Carskadon MA. Sleep and Circadian Influences on Blood Alcohol Concentration. Sleep. 2023 Sep 26:zsad250. doi.org/10.1093/sleep/zsad250