<International Circulation>: Some studies have shown that ischemic stroke， sudden death and myocardial infarction usually occur at daybreak， and blood pressure will rise after midnight. Some doctors think that classification of morning hypertensive patients into groups with or without evening hypertension may be useful for evaluating patients’ total cardiovascular disease risk. Do you agree with them?

    《国际循环》：研究表明，缺血性卒中、猝死和心肌梗死通常发生在清晨，而血压在午夜后也会升高。有的医生认为清晨高血压应区分为是否并存夜晚高血压，这种分类可能有助于评价患者总体心血管疾病危险。您同意吗？

　　prof  Papademetriou:  I think that’s a very good question and what you have stated is true. A lot of cardiovascular events (strokes， heart attacks， sudden deaths， and a lot of arrhythmias) tend to happen more frequently in the early morning between 4am and 10 am when people are waking up and getting out of bed. This is related to the defensive mechanisms of the body to prepare for the difficulties of daily life hence producing more catecholamines which raise the blood pressure， increasing blood flow to the brain and the heart getting it ready， but at the same time they can cause arrhythmias， increase in blood pressure and can cause plaque ruptures. That is why I think we see more events in the morning hours. This occurs as the patient is beginning to wake up， not during actual sleep. During sleep， we know from our ambulatory blood pressure monitoring， that pressure is low and most of the patients have lower pressure while asleep than when awake. These are the so-called dippers. These patients have less risk of cardiovascular events. Those that do not drop their pressure during sleep are at higher risk. At the same time， those who have an excessive increase in blood pressure in the early hours， after four or five o’clock， are at increased risk of developing cardiovascular events.

        Papademetriou教授：这个问题问得好，你说的没错。很多心血管事件（脑卒中、心脏病、猝死和心律失常）出现在早晨4-10点，这正是人们清晨醒来或起床的时间。这与人体的防御机制有关，这种机制为应对日间困难提供必要准备，通过产生更多的儿茶酚胺（可升高血压）增加脑和心脏的血流使它们对困难有所准备，但同时也可导致心律失常、血压升高以及斑块破裂。这就是清晨事件为什么更多的原因。上述过程是在患者开始醒来时发生的，而不是在睡眠过程中。由动态血压监测可以知道，血压在睡眠时较低，大多数人睡眠血压均低于清醒血压，这就是所谓的勺型血压。勺型血压者心血管疾病危险较低，而睡眠血压不下降或清晨4点/5点左右血压极度升高者，心血管事件发生风险较高。