[Effect of sympathetic nervous system on circadian rhythm of blood pressure].

There is evidence that the abnormal circadian rhythm of blood pressure (BP), such as absent of nocturnal BP fall and exaggerated morning BP surge, assessed by ambulatory BP monitoring is associated with cardiovascular events independent of BP levels in hypertensive patients. The activation of the sympathetic nervous system (SNS) is one of the most important pathophysiological mechanisms underlying abnormalities in circadian BP by affecting cardiac output, salt and volume balance in the kidney, and peripheral vascular resistance. In treating hypertension, especially accompanied by the abnormal circadian rhythm of BP, the effect of antihypertensive drug on SNS activity, as well as the timing of drug administration or the duration of the drug efficacy, should be considered.