Circadian variation in blood pressure: considerations for therapy

Accurate measurement of blood pressure is a primary requirement of studies in hypertension and its treatment. However, this is not an easy objective to achieve with sphygmomanometric methods of measurement. Intra-arterial monitoring is an objective method of blood pressure measurement that has become popular in studies of hypertension since its introduction in the 1960s. Since that time the technique has been used to characterize the now well-accepted physiological variability in blood pressure. The clinical significance of such observations is still the subject of active debate. However, it seems clear that, as blood pressure rises sharply in the morning and this occurs at around the same time as the peak incidence of serious cardiovascular events, antihypertensive therapy should control blood pressure effectively at this time. This article summarizes results from some studies, using intra-arterial blood pressure monitoring to indicate the importance of blood pressure variation, 24-h blood pressure control and experience with antihypertensive drugs of various pharmacological classes.