Stress is assumed to be intrinsic to interpreting and the ability to manage it a presumed predictor of performance. And yet, empirical research on the role of stress in interpreting has remained scarce. This study explores the impact of stress and anxiety on the academic scores, heart rate (HR) and speech rhythm of 23 student interpreters in a liaison interpreting task. Participants' stress and anxiety are measured using HR measures and the STAI test. Their speech rhythm is automatically analyzed through different indexes deriving from the variability of syllabic intervals. Results show that students' grades negatively correlate with their levels of state anxiety, which are, in turn, significantly related to their rhythmic parameters in L1-L2 interpreting. Greater rhythmic variability correlates with students' lower examination scores when speech is delivered into their L2. A significant increase in mean HR is reported during the interpreting task phase as compared with baseline and recovery phase, suggesting that HR was a sensitive marker to detect the students' stress response, but not to the level of influencing performance. Results point to the need to triangulate different measures to obtain a complete picture of how stress and anxiety may impact interpreting performance.