Neurohumoral cardiovascular responses to alcohol and their modulation by peroral fluid

Reports on the physiologic effects of acute alcohol are far from uniform and probably reflect differences in study designs, which seldom or never consider the effects of coadministered volumes. We therefore measured blood pressure, heart rate, and heart rate variability (HRV) by power spectrum analysis, baroreceptor sensitivity, arterial blood flow, pulsed-wave velocity (PWV), and plasma levels of vasoactive hormones according to 2 protocols: group A = alcohol, 1 g/kg body weight, mixed with 500 ml of juice; and group B = similar to A plus 750 ml of mineral water. Each group comprised 9 healthy men, studied before and during the subsequent 1 and 1/2 hours after finishing the alcohol. In A, but not in B, alcohol increased heart rate (p = 0.01) and lowered systolic pressure (p <0.05). Plasma renin activity decreased only in B (p <0.01). Atrial natriuretic factor decreased in A, but increased in B (both p <0.02). Pancreatic polypeptide decreased (both p <0.001), and catecholamines did not change. In both groups, alcohol reduced PWV and increased blood flow. Baroreceptor sensitivity and the high-frequency band of HRV decreased in both groups. The physiologic response to acute administration of alcohol appears to depend on the volume of coadministered volumes. Alcohol further appears to interfere with vagal, rather than with sympathetic activity.