Cognitive appraisal of stress can influence performance. Increased awareness could facilitate titration to optimal stress levels. This study's primary aim was to investigate whether physiologic variables change with increasingly stressful simulations. Secondary aims include effect of stress on procedural competency and whether individuals recognize their experienced stress.This was a single-center, mixed-method, simulation-based study. Participants completed three scenarios requiring resuscitation under increasingly stressful conditions. Wearable biometric devices recorded physiologic parameters. Subjects completed surveys assessing knowledge and perceived stress. Intubation success or failure was noted. Heart rate variability (HRV) analysis was used as a proxy for stress.Twelve participants completed the study. Survey analysis revealed progressive amplification of endorsement of affective states associated with stress. Median low frequency (LF)/high frequency (HF) ratio from scenario 1 (median = 2.29, IQR = 1.97, 3.91) was significantly lower than scenario 2 (median = 4.7, IQR = 2.32, 8.35, p = 0.04) and scenario 3 (median = 4.63, IQR = 2.2, 7.43, p = 0.04). Changes in HRV were noted during all scenarios irrespective of subjective self-assessment of stress. Procedural proficiency suffered during more stressful scenarios.This study demonstrates alterations in subjective assessment and objective physiologic data in simulations with increasing stress. HRV is useful as a proxy for stress response and does not always correlate with perception.