DIURNAL CHANGES IN BLOOD PRESSURE AND PULSE RATE ANALYZED BY THE COSINOR METHOD

Abstract

Diurnal rhythm of blood pressure and pulse rate were analyzed by the cosinor method in 7 normal volunteers and 9 patients with mild essential hypertension. Noninvasive ambulatory blood pressure monitoring, ABPM-630 (Colin, Japan) was used, which was reliable judged from the values compared with the recordings of the direct method or the readings of a sphygmomanometer. The cosinor method revealed that 1) all normal individuals had significant diurnal rhythm in which the acrophase was in the afternoon ; 2) hypertensives also had significant diurnal rhythm, 5 in systolic blood pressure and 6 in diastolic blood pressure : 3) fluctuation of the pulse rate also showed significant diurnal rhythm with acrophase in the afternoon in both normals and hypertensives, though the diurnal rhythm in 2 hypertensives was obscure. Mesor values in systolic and diastolic blood pressure correlated well with their respective readings of blood pressure determined at the outpatient clinic. We concluded that the cosinor method is useful for analyzing the diurnal rhythm of blood pressure and pulse rate.