Diurnal Rhythms, the Renin-Angiotensin System and Antihypertensive Therapy

Michael Schachter


Br J Cardiol. 2004;11(4) 

In This Article


There is no doubt that circadian rhythms are of importance in determining risk from cardiovascular events and that these are related, at least in part, to changes in blood pressure and heart rate. These, in turn, are partly regulated by the autonomic and renin-angiotensin systems. We also know that the changes in blood pressure can be modified by existing therapies, including those aimed at the sympathetic nervous system and the renin-angiotensin system, specifically the angiotensin AT1 receptor. But there are several important points which are still unclear, of which perhaps the most important is: which of the treatments available is the most likely to improve outcomes and to what extent is the blunting of the early morning rise in blood pressure relevant in any improvement? It is also interesting to speculate whether the timing of drug administration matters, even for long-acting agents, which might perhaps be given in the evening for optimal effect.[22] As ever, one can also ask whether the mechanism of the blood-pressure lowering matters, or just the ultimate effect?