Wright's (1996) integration of motivational intensity theory ( Brehm & Self, 1989 ) and Obrist's (1981) active coping approach predict that cardiovascular reactivity in active coping depends on the importance of success when task difficulty is unclear. Despite the support for this perspective, one of the basic hypotheses—the mediation of these effects by beta‐adrenergic activity—has not been tested yet. To close this gap, participants worked on a delayed‐matching‐to‐sample task and could earn either 1, 15, or 30 Swiss Francs for a successful performance. Results showed that preejection period reactivity—an indicator of beta‐adrenergic impact on the heart—increased with increasing incentive value. Thus, this experiment closes a gap in the support of Wright's model by demonstrating that beta‐adrenergic reactivity is associated with incentive value under conditions of unclear difficulty.