Acute moderate alcohol consumption affects cardiovascular responses in healthy males with different tolerance levels

We investigated the effect of acute moderate alcohol consumption or placebo on respiratory sinus arrhythmia (RSA) in 48 healthy participants with different levels of alcohol tolerance but no abuse. In the electrocardiogram recording, auditory stimuli were presented at defined points in the respiratory cycle, which allows a non-invasive measure of CNS control over RSA. After alcohol consumption we found a decrease in RSA with auditory stimulation. Moreover, individuals with low tolerance showed only a slight change in the RSA after alcohol intake compared to baseline, whereas the placebo drink led to a reduced RSA. In subjects with high alcohol tolerance, alcohol consumption led to a reduction of RSA, with no change after placebo. These results suggest a centrally driven influence on RSA that is changed by alcohol ingestion depending upon subjects' levels of alcohol tolerance.