Is elevated blood pressure level associated with higher cardiovascular responsiveness in laboratory tasks and with response specificity?

Cardiovascular responsiveness and response specificity were investigated in male students, 48 with moderately elevated blood pressure (systolic blood pressure [SBP] > 140 mmHg and/or diastolic blood pressure [DBP] > 90 mmHg), 31 with mildly elevated blood pressure, and 57 with normal blood pressure. The behavioral tests and physically demanding tasks in the laboratory included mental arithmetic, free speech condition, cold pressor test, upright tilt, and ergometer exercise. Subjects with elevated blood pressure differed in baseline, task, and recovery levels of SBP, DBP, and heart rate. There were no significant effects in task-baseline differences or in residualized change scores. However, a positive initial-value dependency (LIV) in blood pressure responses was found: elevated blood pressure is associated with a larger increase under task conditions. Response scaling that employed reliability estimates and true difference scores indicated higher responsiveness in subjects with moderately elevated blood pressure and, thus, are in accordance with the positive LIV as compared with response measures based on task-baseline differences or residualized change scores. Findings from the specificity analysis indicated a higher incidence of SBP responders, that is, subjects with maximum response in SBP, among subjects with elevated blood pressure. Some of the inconsistencies in the literature with respect to blood pressure responsiveness and heart rate level in individuals with borderline hypertension may be attributed to the specific method of response scaling and to insufficient habituation to the setting and measurement.