Changes in blood pressure and autonomic reflexes following regular, moderate alcohol consumption

Blood pressure, heart rate and responses to a range of autonomic reflex tests were studied in 10 normotensive male volunteers following 7 days of regular alcohol consumption (0.8 g/kg per day) or 7 days of abstaining from alcohol in a crossed, random order, open study. Systolic and diastolic pressures were significantly higher following alcohol intake than the alcohol-free control period (mean rise of 3.0 mmHg systolic and 3.1 mmHg diastolic, P less than 0.05 and P less than 0.01, respectively). Regular alcohol consumption attenuated the rise in blood pressure during isometric exercise and hand immersion in ice water, but did not affect blood pressure or heart rate responses to bicycle exercise. Resting, supine plasma noradrenaline levels, increases in noradrenaline levels during sympathetic activation and vagal reflexes (standing to lying test, diving reflex and Valsalva manoeuvre) did not differ significantly between the alcohol and control phases of the study. These findings support previous evidence that regular alcohol consumption decreases adrenoceptor mediated cardiovascular reactivity. However, the relationship between this effect and the rise in blood pressure that follows regular, moderate alcohol consumption remains unclear.