ABSTRACTBackground and objectives: Effects of reappraising stress arousal during an interpersonal competition were tested on physiological functioning and performance. Additionally, the moderating role of gender was explored.Design and method: Participants (N = 279) were randomly assigned to a stress reappraisal, stress-is-debilitating, or a neutral control condition. Reappraisal materials educated participants about the adaptive benefits of stress, whereas stress-is-debilitating materials instructed participants to avoid stress. Control materials did not mention stress. Participants then competed against a gender-matched confederate on a 10-minute math performance task while cardiovascular reactivity was assessed. Participants were instructed to complete math problems as quickly and accurately as they could and were informed that a winner and loser would be determined by the resulting math scores.Results: Reappraising stress arousal led to more adaptive challenge-like cardiovascular responses, but no condition effects were observed on math performance. Exploratory analyses revealed that reappraisal instructions were effective for improving physiological functioning and facilitating performance for men, but women were unaffected by the manipulation.Conclusions: Reappraising stress arousal can improve physiological functioning during interpersonal competitions, but effects may be limited to men. Implications for future research are discussed.