Individual Differences in Heart Rate and Peripheral Vascular Responses to an Extended Aversive Task

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Abstract
Psychophysiological research on situations requiring active coping has to this point dealt primarily with cardiac responses. Recent studies of vascular responses to such stressors have found conditions in high cardiac reactors that are possible precursors to autoregulatory vasoconstriction. The present study exposed 32 healthy male undergraduates to a one-hour shock avoidance procedure, with avoidance made contingent on video-game peformance. Subjects also participated in a separate counterbalanced baseline session. The relationships among individual differences in heart rate, forearm blood flow, forearm vascular resistance, and digital blood volume pulse responses at different points in the stress session were examined. Decreases in forearm vascular resistance were observed only among high and medium heart rate reactors. As the session progressed, however, forearm vascular resistance responses of the medium heart rate reactors were sustained whereas those of the high heart rate reactors habituated despite the fact that heart rate and forearm blood flow responses remained elevated. The potential implications of this pattern of results to an autoregulation theory of hypertension development are discussed. Heart rate reactivity was inversely related to performance on the video-game task but was unrelated to Type A or anxiety.