Dose-dependent biphasic effect of ethanol on 24-h blood pressure in normotensive subjects

The vasodilation that follows acute alcohol intake is hard to conciliate with the high prevalence of hypertension detected in those persons who consume regular amounts of alcohol. In this experiment we examined early and late hemodynamic effects of acute administration of water and of 15 g, 30 g, and 60 g of alcohol in 40 normal men, aged 19 to 30 years, using 24-h ambulatory blood pressure monitoring (ABPM). Mean systolic and diastolic blood pressures were each approximately 4 mm Hg lower during the period immediately after ingestion of 60 g (v 0 g) of ethanol, and were 7 and 4 mm Hg higher, respectively, at night. The day minus night differences displayed a dose-response curve both for systolic (P < .001) and diastolic blood pressure (P = .045). Three subjects in the 60-g group had more than 50% of nightly blood pressure loads in the hypertensive range against none in the remaining groups (P < .01). In conclusion, our findings suggest that acute alcohol intake elicits a biphasic hemodynamic response, causing, first, vasodilatation and, later, a pressor effect. The higher prevalence of hypertension in alcohol abusers seen in epidemiological surveys may be, in part, a result of measurements done in the period of transiently increased blood pressure during ethanol washout.