The present study investigated how trait intolerance of uncertainty (IU) and individual task appraisal relate to the stress and performance of law enforcement students. Participants were recruited from Royal Canadian Mounted Police (RCMP) Depot Division training academy. The participants completed a series of questionnaires measuring IU and task appraisal and performed a simulated emergency driving and use-of-force scenario. Arousal was measured through heart rate (HR) that was recorded using a wearable biometrics device, the Hexoskin® Smart Shirt. IU and task appraisal were highly correlated but had no association with either arousal or performance on either aspect of the task.