IMPEDANCE CARDIOGRAPHY USED TO ASSESS PATTERNS OF CARDIOVASCULAR-RESPONSE TO BEHAVIORAL STRESSORS

This paper presents two examples of how impedance cardiography may be used to interpret the hemodynamic influences on blood pressures measured during behavioral stress. In Study 1, blood pressure changes which were similar during two tasks were shown to have important differences in their cardiac output and vascular resistance components. During work on a reaction time task having aversive incentives compared with a neutral task, the blood pressure changes were seen to be associated with lowered vascular resistance and raised cardiac activity, a ''fight-flight'' pattern. In Study 2, blood pressure response differences between two subject groups working on an identical task were found to have blood pressure changes differing in their underlying cardiac and vascular components as measured by impedance. Such uses of impedance cardiography have widespread potential application in psychophysiological research with humans.