Reproducibility of blood pressure values in normotensive subjects.

The reproducibility of whole-day blood pressure (BP) averages was evaluated in 56 normal volunteers. Blood pressure was monitored using a non-invasive automatic device that measured BP at 7.5 minute intervals for a 24h period. The whole-day systolic BP averages were closely similar on the two study days, 119 +/- 10 (S.D) and 117 +/- 11 mm Hg. A difference between the two whole-day averages of systolic blood pressure of greater than 10 mm Hg was found in 10 subjects. Values for the diastolic BP averages were 75 +/- 7 and 73 +/- 8 mm Hg with differences of greater than 5 mm Hg found in 15 subjects. Strong consistency of BP averages during the separate study days was also found for shorter monitoring periods: the 2h period (8 AM to 10 AM), the daytime period (6AM to 10PM) and the nighttime period (10PM to 6AM). Thus, blood pressure values obtained using a non-invasive ambulatory monitoring device are reproducible in the majority of normotensive control subjects.