Learned Control of Decreases in Systolic Blood Pressure

Abstract

A NUMBER of studies have demonstrated that when humans are provided with exteroceptive feedback of specific aspects of cardiovascular performance, they rapidly learn to control responses of the system in question. Increases and decreases in heart rate¹, decreases in heart rate variability², and changes in vasomotor tone³ have all been demonstrated to be subject to control under conditions of augmented sensory feedback. The findings suggest that the use of augmented sensory feedback may be effective in the training of other aspects of cardiovascular behaviour. Such a technique would be particularly valuable in the training of blood pressure decreases in individuals exhibiting chronic essential hypertension. Recently Shapiro, Tursky, Gershon and Stern⁴ gave one group of subjects a brief signal whenever their systolic blood pressure exceeded a prescribed value and another group of subjects a brief signal whenever their blood pressures fell below a prescribed value. Using this procedure and making reinforcement depend on the appropriate response, these investigators were able to produce average increases and decreases in systolic blood pressure of about 1 and 5 mm Hg respectively in their two groups of subjects. If these general procedures could effect greater decreases in blood pressure, their potential therapeutic utility would be enhanced. Following the finding by Brener, Kleinman and Goesling⁵ that the degree of cardiovascular control is a direct function of the amount of augmented sensory feedback provided during training, we have attempted to maximize the amount of blood pressure information fed back to subjects within the constraints of the monitoring system used.