Poincaré plot indices as measures of sympathetic cardiac regulation: Responses to psychological stress and associations with pre-ejection period.

The Poincaré plot is a visual representation of the R-R time series within a Cartesian plane constructed by plotting each R-R interval as a function of the previous one. The plot can be characterized by parameters that quantify the standard deviation (SD) of short- and long-term R-R interval variability (SD1 and SD2, respectively). Claims regarding the use of Poincaré plot analysis as an alternative to conventional time-domain and spectral analytic measures of parasympathetic contributions to heart rate variability (HRV) have been evaluated somewhat extensively.

Dispositional Optimism and Cardiovascular Reactivity Accompanying Anger and Sadness in Young Adults.

Background: Dispositional optimism, a generalized expectation for positive outcomes, appears to promote physical health and well-being, including positive effects on cardiovascular disease outcomes. Mechanisms may involve adaptive responses to psychological stressors that dampen their physiological impact.

Purpose: This study investigated (i) whether individual differences in optimism are associated with attenuated cardiovascular reactivity (CVR); (ii) whether the CVR moderating effect of optimism differs for two stress emotions, anger and sadness; and (iii) whether separate measures of optimism and pessimism, and the more commonly used measure that combines them, differ in their relationships with CVR.