Since there is both acute and longer-term tolerance to the effects of alcohol, differences between light drinkers and heavy drinkers following a standard drink would be expected. However, since light drinkers and heavy drinkers are self-selected for this behavior, it has not been possible to fully attribute all differences in the response to a standard drink or light and heavy drinkers to the amount of alcohol consumed. Some of the differences may be due to innate differences between the individuals that self select to drink more alcohol. When light drinkers and heavy drinkers are compared the heavy drinkers report more stimulation in the ascending part of the blood-alcohol curve and less sedation during the descending portion.

female moderate drinkers
Tolerance to repeated alcohol ingestion may account for findings illustrated in 2nd figure where moderate drinkers have less impairment of locomotive function and cognitive function and report less bad effects of alcohol than light drinkers following a single drink.

Heavy Drinkers Have Increased Stimulation and Decreased Sedation after Drinking Alcohol Compared to Light Drinkers

During the rising blood alcohol curve (BAC) heavy drinkers have more stimulation and during the falling BAC they have less sedation than light drinkers. 20 heavy drinkers (16.3 drinks/week) and 14 light drinkers (2.3 drinks/week) drank placebo or alcohol 0.4 or 0.8 gm/kg on 3 separate days and completed ratings (mean age about 28 and 80% and 71% males heavy and light drinkers respectively). Data from the 0.8 gm/kg dose illustrates increased stimulation on the rising curve and decreased sedation on the falling curve for the heavy drinkers. Stimulation and sedation scales are the sum of 7 items for each scale rated 0-10. (Constructed from data in King AC, et al, Alc Clin Exp Res, 26:827, 2002)