This study evaluates the impact of evening alcohol consumption on sympathetic activity and baroreflex function in binge drinkers. Our central hypothesis is that evening binge alcohol consumption will lead to sympathetic overactivity and blunted baroreflex function.
This study will recruit male and female binge drinkers who will participate in a randomized, cross-over, double-blind, placebo-based study to examine the impact of an evening of alcohol vs. placebo/fluid-control on autonomic and cardiovascular control at night and the subsequent morning. The study will utilize established techniques for assessing sleep (polysomnography) and autonomic/cardiovascular control (microneurography, beat-to-beat finger plethysmography, electrocardiogram, etc.). All subjects will undergo a familiarization night in the sleep laboratory prior to their first randomized test session with either alcohol or placebo/fluid-control. Both men and women will be tested to address a secondary aim of determining the impact of sex (male vs. female) and ovarian cycle (early follicular vs. midluteal phase) on sympathetic neural responsiveness to evening alcohol in binge drinkers. Finally, as a tertiary/exploratory aim, participants that have a respiratory disturbance index of ≥5 episodes per hour during the alcohol treatment will be asked to consider one additional overnight session where they will be randomly assigned to either continuous positive airway pressure (CPAP) or sham-CPAP for one additional night of evening alcohol consumption.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
69
Using a randomized, cross-over design, all subjects will consume evening alcohol (and a fluid-control placebo) in a dose that mimics binge drinking.
Montana State University
Bozeman, Montana, United States
Sympathetic Nerve Activity Burst Frequency
Direct recordings of muscle sympathetic nerve activity (MSNA) from the peroneal nerve using a microelectrode.
Time frame: 1 month
Sympathetic Nerve Activity Burst Incidence
Direct recordings of muscle sympathetic nerve activity (MSNA) from the peroneal nerve using a microelectrode. Burst incidence is calculated as the number of sympathetic bursts per 100 heartbeats. This measure takes into account varying heart rates on sympathetic activity by normalizing to each individual's heartbeat. Higher calculated number equates to higher sympathetic activity.
Time frame: 1 month
Spontaneous Sympathetic Baroreflex Sensitivity
The linear relationship between beat-to-beat blood pressure and sympathetic nerve activity expressed as bursts/100 heart beats. Sympathetic baroreflex sensitivity is determined using the slope of the weighted linear regression of diastolic blood pressure and MSNA burst incidence. Diastolic blood pressure values of individual cardiac cycles were binned into 3 mmHg intervals, and the MSNA burst incidence was determined and subsequently plotted against corresponding diastolic blood pressure bins.
Time frame: 1 month
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