Blood Pressure and Heart-Rate Response to Verbal Instruction and Relaxation in Hypertension

Abstract

Recent data have suggested that instructional set and task awareness may play a substantial role in the achievement of directional changes in blood pressure associated with “operant conditioning” techniques. Six hypertensive patients were instructed alternately to raise (UP) and lower (DOWN) their blood pressure by concentrating on changing “heart rate, force of contraction, and blood vessel resistance to flow.” Paired 10 min periods were separated by the experimenter's entry and exit. Five of the subjects were taught progressive muscular relaxation (PMR), and the protocol repeated, with PMR induced throughout this session. The immediate cardiovascular response to PMR, induced in both the presence and absence of the experimenter, was studied. Systolic (SBP) and diastolic (DBP) blood pressure and heart rate (HR) were measured every 30 sec in all sessions. Direction of changes in BP and HR for UP and DOWN periods was appropriate and significant in both instruction sessions, and these differences for BP frequently reached significant levels of magnitude. In general, interactions for HR did not reach significant levels. Comparison of the two sessions yielded little difference between them. PMR uniformly lowered BP and HR, but was of significant magnitude only when induction of PMR involved the active participation of the experimenter. Interview data revealed considerable dramatic mental imagery associated with directional shifts in BP. The results indicate that directional instruction may result in appropriate changes in BP and HR of a magnitude comparable to those reported in studies using “external biofeedback.” PMR did not alter the response. This study adds to other data which point to the potential for nonspecific or “placebo” effects to be operative in conditioning studies.