Spontaneous blood-pressure variations in hypertension; the effect of antihypertensive therapy and correlations with the incidence of complications

Abstract

Since indirect methods of measuring blood pressure were intro duced into clinical practice at the end of the last century, many investigators have studied the variations in blood pressure occurring during the day and over longer periods (cf. summaries of the literature by Menzel, 1961, 1962; and Richardson et al., 1964). The earliest studies, e.g. the findings of Zadek, published in 1881, were of limited value, owing to the technical inadequacy of the apparatus available; in others, the blood pressure was measured only at fairly long intervals, or not consistently over 24 hours. Although the results are divergent in a few cases, most of these investigations reveal that blood pressure may vary considerably, not only from day to day, but also in the course of one and the same day, the lowest values appearing during the night and the highest in the morning or, as is more frequently the case, in the early evening.