Acute and chronic alcohol tolerance in humans: effects of dose and consecutive days of exposure.

Male social drinkers received doses of either 0.75 or 1.0 g/kg body weight of alcohol over 5 consecutive days. The beverage was divided into three equal drinks, and subjects performed an eye-hand coordination motor task after each drink. The breath alcohol concentration (BAC) was assessed at each performance measurement period. Performance was also assessed when the BAC level on the descending limb of the BAC curve was similar to each of the three BAC measurements on the ascending curve. Each group developed chronic tolerance (comparing the daily postalcohol performance with the daily prealcohol performance) by the 4th day of exposure. The development of a degree of acute tolerance (assessed by comparing the performance on the ascending and descending limbs of the BAC curve) was not observed consistently in the 1.0 g/kg dose group, but was seen in more than half of the subjects in the 0.75 g/kg dose group by the 4th and 5th day of exposure.