Relationship of Resting Baroreflex Activity to 24-Hour Blood Pressure and Mood in Healthy People

Objectives: Previous research suggests that mechanisms related to afferent and efferent components of the baroreflex are associated with blood pressure level and mood, and that mood as a component of subjective well-being may be mediated by changes in blood pressure. This study examines these mechanisms in 213 healthy women and men. Methods: Evaluation of spontaneous baroreflex activity using the sequence technique under resting conditions in the laboratory was followed by 2 days of 24-h ambulatory blood pressure recording and diary ratings of mood. Results: Patterns of components of the baroreflex loop were significant predictors of 24-h ambulatory blood pressure mean level, its circadian variability, and daily ratings of mood. Three mechanisms were found to be involved in the regulation: (1) interaction between gains of afferent and efferent cardiac components of the baroreflex, (2) gain of afferent signals related to fast cardiac responses to baroreceptor activation, and (3) gain of afferent signals related to late cardiac responses to baroreceptor inhibition. The interaction of afferent/efferent components of baroreflex loop appears to independently determine mean levels of systolic blood pressure and positive (happy) mood. The effect of the baroreceptor activation mechanism on subjective well-being (indexed by happy and alert moods) was mediated by the wake/sleep systolic blood pressure difference. Additionally, the baroreceptor inhibitory mechanism effect on subjective well-being (indexed by stressed and sleepy moods) was mediated by the wake/sleep diastolic blood pressure difference. Conclusions: Evaluation of the baroreflex components and their interaction provides important information about blood pressure and mood beyond that provided by baroreflex sensitivity and potential for the evaluation of risk for hypertension and mood disturbance in healthy people.