Circadian Rhythm of Blood Pressure

Circadian rhythms synchronize human physiological changes with the day and night cycle. However, with the invention of artificial lighting, the consequences of disrupted rhythm also started showing in various areas of human health including vital parameters such as blood pressure. It is one of the strictly regulated variables in the cardiovascular system and thus understanding its variability is significant. The normal circadian variation in blood pressure is characterized by a 10%–20% reduction in the night recordings and the individuals with this decrease in the night-time blood pressure are termed “dippers,” a blunted decline in night-time blood pressure is seen in “nondippers.” Evidence suggests a relatively increased risk of cardiac and extracardiac morbidity in individuals with nondipping blood pressure patterns. The purpose of this review was to summarize the literature regarding various factors contributing to circadian variations in blood pressure and explore the role of chronotherapy in hypertension. We found that there is conflicting evidence to suggest the role of night time administration of antihypertensive drugs, but the understanding of these mechanisms can be utilized for strategic management of hypertension and suggests that if drugs are aligned with the circadian rhythm then may be useful in not only controlling hypertension but also improving cardiovascular outcomes.