We studied how closely changes in electronically monitored physical activity are reflected in changes in blood pressure and heart rate in a group of untreated hypertensive subjects. Thirty-nine hypertensive patients (office blood pressure > 140/ 90 mm Hg) of mean age 57 +/- 10 years (mean +/-SD) wore an ambulatory blood pressure monitor and a wrist actigraph simultaneously. Both average and peak activity for 5 min before each valid blood pressure reading were determined, as was average activity for awake and sleep periods, determined by patient kept diaries. For the overall group, awake and 24-h activities were inversely correlated to age (n = 39, r = -0.42; P = 0.01 and n = 39, r = -0.38; P = 0.01, respectively). No correlation was found between group awake activity and group-average blood pressure or heart rate. For individual patients, there was marked variation in the degree of correlation between awake activity measures (both peak and average) and blood pressure and heart rate. The strongest positive correlation was between activity levels and the heart rate-pressure product. Nondipper profile hypertensives had higher sleep activity than dipper hypertensives (44 +/- 28 units/min v 25 +/- 20 units/min, df = 37, t = 2.12; P = 0.04), but awake activity levels were similar. The higher sleep activity remained after adjustment for age. These findings indicate that the relationship between actigraphic activity and hemodynamic parameters is highly variable and that the rate-pressure product is the strongest correlate of short-term activity. Furthermore, hypertensives with the nondipper profile have higher sleep activity than dipper hypertensives. These findings stress the need for further study into the role of day-to-day activity in determining ambulatory blood pressure and heart rate variability.
To determine the presence of cardiac disease in hypertensive patients with disparities between physician and out-of-office blood pressures, we prospectively studied three groups of age-matched patients identified by both casual (office) and ambulatory blood pressures: (1) office blood pressure greater than 140/90 mm Hg and awake ambulatory blood pressure of 130/80 mm Hg or less ("office" hypertensives); (2) office blood pressure less than 135/85 mm Hg and awake ambulatory blood pressure of 130/80 mm Hg or less (normotensives); and (3) office blood pressure greater than 140/90 mm Hg and awake ambulatory blood pressure of 140/90 mm Hg or greater ("daytime" hypertensives). In the patients with office hypertension, both the left atrial index and left ventricular mass index were significantly less than in patients with daytime hypertension and not statistically different from those of the normotensive subjects. Left ventricular filling rate at rest and ejection fraction at peak exercise were significantly greater in the office hypertensive group than in the daytime hypertensive group but were no different from those of the normotensive subjects. These findings demonstrate that patients with blood pressure elevation only in the physician's office have cardiac size and function similar to those of normotensive individuals. Thus, the average daily blood pressure best predicts cardiac end-organ damage.
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