AGE-RELATED DIFFERENCES IN BLOOD ETHANOL PARAMETERS AND SUBJECTIVE FEELINGS OF INTOXICATION IN HEALTHY MEN

Healthy men within 4 age groups, 20–29, 30–39, 40–49and 50–59 years (N = 12 per group), drank 0.68 g/kg ethanolas neat whisky after fasting overnight. The drink was finishedwithin 20 min and the concentrations of ethanol in capillaryblood were determined at 30/60 min intervals for 7 hr. At thetime of blood sampling, the men were asked to estimate theirfeelings of intoxication according to an arbitrary scale onwhich the score 10 indicated ‘tipsy’ or a ‘Littlehigh’. The time course of blood ethanol concentrationwas similar in all 4 groups with the curve for 50–59-year-oldmen on the highest level and 20–29-year-old men lowest.Subjective intoxication scores were significantly less in theyoungest age group and the maximum score for each subject wascorrelated with age (r = 0.45, P << 0.01). Total bodywater (TBW) was not correlated with age directly (r = 0.17,P > 0.05) but when it was expressed as percent of body weighta strong negative correlation was found (r = –0.77, P> 0.001). The mean total body water estimated from ethanoldilution was 46.7 ± 4.11. (+ SD, N = 48) and this correspondsto 58% of mean body weight of the men. The distribution volumeof ethanol/kg body weight (V_d) decreased with ageing (r = –0.59,P < 0.001) being 0.72, 0.71, 0.68 and 0.66 l/kg on averagein the 20–29, 30–39, 40–49 and 50–59-year-oldage groups respectively. The reduction of V_d corresponds toan age-related decrease in the percentage of body water andan increase in the percentage of body fat. This results in elevatedblood ethanol concentrations in older individuals for a constantdose/kg body weight. The absorption of ethanol from the gutand its rate of disappearance from blood were not markedly influencedby age. The lower subjective feelings of intoxication reportedby younger men may indicate that age-related differences inacute functional tolerance to ethanol or different thresholdvalues of blood ethanol may exist before an effect is felt.