Effects Of Age And Gender On The Circadian Rhythm Of Blood Pressure And Endothelial Vasoactive Substances

Objective: Most of kinds of vital phenomena show biological rhythms. Biological rhythms are universal phenomena in living organisms, including human. Biological rhythms can be divided into 3 types on the basis of their cycle lengths: 1) circadian (or diurnal) rhythms with a period of approximately 24 hours; 2) ultradian rhythms, with a period significantly shorter than 24 hours (hours, minutes, or even seconds); and 3) infradian rhythms, with a period longer than 24 hours (days, months, or years). Circadian rhythms, which are the rhythms associated with many cardiovascular parameters, are the most common and best studied of these rhythms. In humans, most cardiovascular physiological parameters (such as heart rate, blood pressure, conduction function) and pathophysiological events (myocardial ischemia/infarction, arhythmias, sudden cardiac death) show circadian rhythms. Recent studies have revealed that endothelial vasoactive substances play an important role in cardiovascular system. For example, degrade blood vessel endothelium permeability, decrease adhesion molecule expression, restrain vascular smooth muscle hyperplasy, and so on. Endothelin (ET) and nitric oxide (NO) is a pair of the most representative vasoactive substances. They...