Alcohol Potentiates Orthostatic Hypotension Implications for Alcohol-Related Syncope

Background—Alcohol consumption may be linked to syncopal events. The mechanisms by which alcohol may induce syncope are unknown. Impairment of the response to orthostatic stress may be involved. Using a double-blind, randomized, placebo-controlled study, we tested the hypothesis that short-term alcohol intake causes orthostatic hypotension because of an impairment in the vasoconstrictor response to orthostatic stress. Methods and Results—We examined the effects of alcohol on blood pressure, heart rate, and forearm vascular resistance (FVR) during orthostatic stress achieved by stepwise increases in lower-body negative pressure (LBNP) in 14 healthy young volunteers. During the placebo session, blood pressure did not change significantly during LBNP at −5, −10, and −20 mm Hg. A significant decrease in blood pressure was evident only at −40 mm Hg. In contrast, blood pressure fell significantly at all levels of LBNP during the alcohol session. Compared with placebo, alcohol potentiated the hypotensive respons...