Paramedic work can be stressful. Encountering clinically unwell patients, long shift hours and dealing with the unknown expose paramedics to mental, physical and emotional stress. In the learning environment, these types of stresses are difficult for educators to replicate. Traditionally, students have been tested under pressure in scenario-based situations as a means of stress inoculation. However, the literature is unclear as to whether this enhances or hinders learning. A recent scoping review identified an acceptable level of stress during simulation can be beneficial, although a level of a balance is required. Too much stress can hinder learning and lead to underperformance. Ideally, high-acuity patient scenarios should be designed to invoke a challenging state of appraisal in the student to support both their learning and knowledge retention. To obtain an understanding of how students appraise these types of scenarios, quantitative physiological and psychometric data needs to be obtained and analyzed. However, across the health care education literature, inconsistent methodologies and a variety of physiological and cognitive measures make it challenging to draw firm conclusions. This narrative review searched three prominent databases using common search terms to produce a subset of high-quality publications that we thought were most pertinent and insightful. Our paper establishes recommendations for appropriate physiological assessment and interpterion of challenge appraisal in students undertaking high-stress, low-frequency clinical scenarios.