Immediate and Complex Cardiovascular Adaptation to an Acute Alcohol Dose

Abstract

Background: The detrimental effects of chronic heavy alcohol use on the cardiovascular system are well established and broadly appreciated. Integrated cardiovascular response to an acute dose of alcohol has been less studied. This study examined the early effects of an acute dose of alcohol on the cardiovascular system, with particular emphasis on system variability and sensitivity. The goal was to begin to understand how acute alcohol disrupts dynamic cardiovascular regulatory processes prior to the development of cardiovascular disease.

Methods: Healthy participants (N = 72, age 21 to 29) were randomly assigned to an alcohol, placebo, or no-alcohol control beverage condition. Beat-to-beat heart rate (HR) and blood pressure (BP) were assessed during a low-demand cognitive task prior to and following beverage consumption. Between-group differences in neurocardiac response to an alcohol challenge (blood alcohol concentration ~ 0.06 mg/dl) were tested.

Results: The alcohol beverage group showed higher average HR, lower average stroke volume, lower HR variability and BP variability, and increased vascular tone baroreflex sensitivity after alcohol consumption. No changes were observed in the placebo group, but the control group showed slightly elevated average HR and BP after beverage consumption, possibly due to juice content. At the level of the individual, an active alcohol dose appeared to disrupt the typically tight coupling between cardiovascular processes.

Conclusions: A dose of alcohol quickly invoked multiple cardiovascular responses, possibly as an adaptive reaction to the acute pharmacological challenge. Future studies should assess how exposure to alcohol acutely disrupts or dissociates typically integrated neurocardiac functions.

Keywords: Baroreflex; Blood Pressure; Heart Rate Variability; Intoxication; Vascular Tone.

Fig. 1

Differences in (A) mean heart rate and heart rate variability between groups. Heart rate variability was measured as (B) the standard deviation of all normal-to-normal intervals (SDNN), (C) the root mean square of successive differences (RMSSD), and (D) high frequency heart rate variability (HRV). Error bars represent standard error; ^✜change in alcohol group, p < 0.01; ^§change in control group, p < 0.01.

Fig. 2

Differences in mean stroke volume (top) and stroke volume variability (bottom) between groups pre- and post-beverage consumption. Error bars represent standard error; ^✜change in alcohol group, p < 0.01.

Fig. 3

Differences in vascular tone represented by mean pulse transit time (top) and pulse transit time variability (bottom) between groups from pre- and post-beverage consumption. Error bars represent standard error.

Fig. 4

Differences in mean systolic blood pressure (top) and systolic blood pressure variability (bottom) between groups pre- and post-beverage consumption. Error bars represent standard error; ^✜change in alcohol group, p < 0.01; ^§change in control group, p < 0.01.

Fig. 5

Differences in baroreflex sensitivity pre- and post-beverage consumption in the heart rate (top), stroke volume (middle), and vascular tone (bottom) baroreflex branches. Error bars represent standard error; ^✜change in alcohol group, p < 0.01.

Fig. 6

Graphical depiction of the relationships between pre- to post-beverage changes in heart rate and stroke volume (A), heart rate and pulse transit time (B), and stroke volume and pulse transit time (C) in each participant.

Fig. 7

Graphical depiction of the relationship between pre- to post-beverage changes in systolic blood pressure (ΔSAP) to changes heart rate (top), stroke volume (middle), and pulse transit time (bottom) is shown.