The idea of “holding your liquor” is more complicated than is often understood, even while those who drink frequently may withstand a certain quantity of alcohol more effectively than light and moderate drinkers, according to new research published in Alcohol Clinical and Experimental Research.
Three sets of young people in their 20s with different drinking habits participated in the study. They discovered that after consuming an ordinary intoxicating dose—equivalent to four to five alcoholic beverages that result in breathalyzer readings of 0.08-0.09%, i.e., the legal limit for drunk driving—drinkers with alcohol use disorder (or AUD, also known as alcoholism), showed fewer impairments on motor and cognitive abilities than light or heavy social drinkers.
However, those with AUD demonstrated substantial impairment in those tasks when they drank more than twice as much as they would typically consume, equivalent to seven to eight drinks, and a breathalyzer reading of 0.13%. Their impairment persisted for three hours after drinking. There is a widespread belief that experienced drinkers (those with AUD) become tolerant to alcohol’s depressant effects with continued use, according to Andrea King, Ph.D., professor of psychiatry and behavioral neuroscience at the University of Chicago and senior author of the study.
“We somewhat backed that, but in many subtle ways. Researchers saw substantial declines in fine movement and cognitive tasks when the participants drank liquor in the research at a dose similar to their typical drinking pattern. This was a more significant impairment than a light drinker experiences at the intoxicating level. The study team informed participants they would be given a drink that included alcohol, a stimulant, a sedative, or a placebo in a clinical setting.
It was a flavored drink mix dissolved in water with 190-proof alcohol at 16% volume based on the participant’s weight, which is equivalent to four to five drinks, a high dose thought to be sufficient to make a typical drinker intoxicated (female participants received a dose that was 85% of that for males to account for sex differences in metabolism). The subjects ingested the drink for 15 minutes.
Participants were also asked to rate their level of impairment, from “not at all” to “extremely,” at the 30- and 180-minute intervals. Compared to light drinkers, both AUD and strong social drinkers claimed to feel less impaired. On the motor and cognitive assessments, they did exhibit reduced overall alcohol impairment, but around the 30-minute mark, they slowed down similarly to the light drinkers on the OK motor test. They also returned to baseline levels more quickly, lending credence to the idea that heavy drinkers have more tolerance and are better able to “hold their liquor” than moderate drinkers.
However, those with AUD frequently participate in prolonged drinking and do not stop after four or five drinks. As a result, a portion of the study’s drinkers with AUD took part in a different session when they consumed a beverage more in line with their usual drinking patterns, roughly the equivalent of seven to eight drinks. They displayed more than twice as much brain and motor impairment at this higher alcohol dose than they did following the typical intoxicated dose. They still didn’t return to their previous performance level after three hours.
Their level of intoxication far surpassed that of the moderate drinkers who took the recommended dosage, indicating that the physiological effects of alcohol accumulate the more somebody drinks, whether they are experienced drinkers or not. While the second dose was 50% higher than the first, King said, “We’re seeing more than double the impairment, which surprised me at how much impairment that group had to that larger dose.”