[Effect of alcohol on circadian blood pressure]

The effects of alcohol on blood pressure have been studied extensively. Abstention is recommended in high blood pressure as basic non pharmacological treatment. On the other hand short term lowering of blood pressure by alcohol is known. Blood pressure effects of alcohol vary according to chronicity and amount of intake. It is not known how alcohol affects the 24 hour profile of blood pressure, in particular day- and night-time differences. This explorative study investigates the effects of a single dose of alcohol in the evening on the 24 hour blood pressure profile. Nine individuals with essential hypertension (mean age 65.4 +/- 8.7 years) were compared to 10 normotensives (29.6 +/- 3.0 years). Blood pressure was followed on 2 consecutive days by means of a 24 hour ABPM. On one evening the test persons consumed 0.6 g/kg ethanol before bed time. Apart from the direct comparison of the two groups, effects of body weight and daily alcohol consumption were also considered. For analysis of the 24 hour recording the mean 24 hour values, the mean difference between day and night and loads (fraction of blood pressure > 140/90 mm Hg) as well as heart rate were used. Ethanol led to nocturnal drops of blood pressure in normotensives and hypertensives alike and thus to an increased day/night difference. The latter increased by 2 +/- 4 mm Hg for the systolic and 2 +/- 1 mm Hg for the diastole values in normotensives and by 6 +/- 2 mm Hg and 3 +/- 1 mm Hg, respectively, in hypertensives on the day of alcohol intake. This trend was more marked in individuals with smaller daily alcohol consumption as well as in obese hypertensives. The blood pressure differences were not significant in our test sample because of a large variance in the response. Two normotensives were found to be borderline hypertensives. They exhibited a marked increase of nocturnal blood pressure values above 140/90 mm Hg when compared to the control night. Our study indicates that alcohol consumption should be considered when evaluating 24 hour blood pressure recordings. The blood pressure lowering effect of alcohol during the night is able to modulate the day/night difference can also be useful as diagnostic criterion our data may be clinically relevant.