The normal circadian pattern of blood pressure: implications for treatment.

Blood pressure fluctuates over 24 h following a circadian rhythm that reaches a peak in the morning shortly after awakening. The onset of many acute cardiovascular and cerebrovascular events shows a synchronous cyclical pattern, with the highest incidence of morbidity and mortality in the early morning hours. Strong, although circumstantial, evidence suggests that the early morning surge in blood pressure may contribute to the onset of acute cardiovascular episodes. Sustained blood pressure control that blunts the early morning blood pressure surge may help to reduce the incidence of these events. Antihypertensive agents are needed that provide smooth and sustained blood pressure control for the full 24 h, including the risky early morning hours. The angiotensin II receptor blocker telmisartan given once daily, because of its long half-life and mechanism of action, is likely to confer benefit in terms of 24-h blood pressure control and may reduce cardiovascular risk at the time of greatest patient vulnerability.