The effects of beta-blocker therapy on diurnal variation of blood pressure.

Plotting hourly mean blood pressures recorded continuously by an intra-arterial technique in fully ambulant subjects on a time scale has clearly outlined a circadian biorhythm which is a useful tool for the study of antihypertensive drugs. Studies with beta-adrenoreceptor blocking drugs have shown differences which may have fundamental significance in the clinical usage of these drugs for treating hypertension.