Epinephrine and Norepinephrine Responses in Continuously Collected Human Plasma to a Series of Stressors

&NA; The present study employed continuous blood withdrawal to examine epinephrine and norepinephrine responses to a cognitive stressor (mental arithmetic), active physical stressors (handgrip and knee bends), passive painful stressors (venipuncture and cold pressor), and a medical procedure that was considered nonstressful (blood pressure measurements). The data were analyzed by analysis of variance (ANOVA) and by time series analysis. The ANOVA indicated that epinephrine and norepinephrine increased significantly in response to the stressors. Epinephrine showed a greater increase to the cognitive stressor than to the others. Time series analysis, however, showed a more varied pattern. It indicated that the height and duration of response differed considerably across subjects and across interventions. The results from both analytic procedures are compared and discussed in terms of current hypotheses of catecholamine response.