Circadian Rhythm of Blood Pressure and Its Modulation by the Antihypertensive Drugs in Hypertensive Patients of South Tamilnadu

Abstract

Blood Pressure in humans exhibits a characteristic circadian rhythem with a nocturnal decline ranging between 10% - 20% of daytime values. This nocturnal decline has a high significance as its absence or diminution commonly known as non-dipping phenomenon is implicated in cardiovascular and cerebrovascular complications. Hence, the present study investigated the incidence of dipping (DP) and non-dipping phenomenon (NDP) in a normotensive and hypertensive population of South Tamil Nadu. NDP was observed in the normotensive population also. However the incidence was higher in hypertetnsive population than in normotensive population. In the normotensive population the incidence of DP was higher than NDP as it was high in normotensives aged below 50 and normotensives unemployed. Hence the higher prevalence of DP was dependent ton age and job strain. As unemployed are free from job strain, the incidence of DP was high in them against their employed counterparts and this freedom from job strain contributed to higher incidence of DP in normotensives. DP was lower than NDP in hypertensive population. The same effect was observed in all the subpopulations. So factors like sex, age and freedom from job strain could not reduce the prevalence of NDP in the hypertensive population. So it was concluded that the high NDP did not depend on age, sex and job strain. So, it could be due to hypertension itself. Between the normotensive and hypertensive populations the prevalence of DNP was higher in hypertensive population than in normotensive population furthe suggesting the role of hypertension in NDP. From this study it is clear that antihypertensive drugs cannot fully restore the DP. Hence search for antihypertensive drugs/formulations which could increase the DP in hypertensive population could be a potential area of research. newline newline