THE RELATIONSHIP BETWEEN 24-HOUR AMBULATORY BLOOD PRESSURES AND LABORATORY MEASURES OF CARDIOVASCULAR REACTIVITY

The relationship between 24-hour ambulatory blood pressures (ABP) and blood pressures (BP) obtained during laboratory stressors was examined. Thirty normotensives (equal males and females) underwent ABP monitoring on three occasions separated by a week. They also underwent a laboratory assessment which included standard stressors (ie., mental arithmetic, cold pressor, orthostatic response, treadmill exercise). Correlational analyses found laboratory pressures to be significantly correlated with ambulatory pressures, with laboratory baseline BPs showing higher correlations to the ambulatory BPs than the BPs obtained during laboratory stressors. In addition, gender effects were examined. In the correlational analyses between ABPs and laboratory BPs, males and females did not differ significantly in the strength of the correlations. In terms of absolute values, males were found to have significantly higher SBP during ambulatory monitoring, random-zero recordings, calibration readings, and during baselines of the laboratory assessment. There were no gender effects for these measures with respect to diastolic blood pressure or heart rate. There were also no gender effects on reactivity to laboratory stressors as measured by change scores. Exploratory analyses found no significant effect of history of familial hypertension on either the ABPs or the laboratory pressures.