Ambulatory-determined 24-hour blood pressure in mild hypertensives and in normotensives

Noninvasive ambulatory twenty-four-hour blood pressure (BP) monitoring was carried out in 30 normotensive subjects (16 women, 14 men), aged twenty-five to sixty years (mean thirty-eight) and in 29 mild essential hypertensive patients without target organ damage (14 women, 15 men), aged twenty-three to sixty-one years (mean thirty-nine). Hypertensive patients were not treated, and they discontinued any antihypertensive treatment at least four weeks before the study. During the daytime period (6 AM-10 PM) BP was monitored every fifteen minutes, and during the night (10 PM-6 AM), every thirty minutes. Obviously, mean twenty-four-hour systolic blood pressure (SBP) and diastolic blood pressure (DBP) were higher in hypertensive patients (P < 0.001). There was a persistent correlation in the group of mild hypertensives between successive BP hourly mean readings (r ranged from 0.61 to 0.93 for SBP and from 0.45 to 0.82 for DBP). In normotensive subjects these correlations failed in particular periods: 8 AM-9 AM, r = 0.30 for SBP and 0.45 for DBP; 1 PM-3 PM, r = 0.17-0.49 for SBP and 0.28-0.37 for DBP; 9 PM to midnight, r = 0.21-0.57 for SBP and 0.23-0.38 for DBP.