BACKGROUND The adverse effects of stress on the wellness of trauma team members are well established; however, the level of stress has never been quantitatively assessed. The aim of our study was to assess the level of stress using subjective data and objective heart rate variability (HRV) among attending surgeons (ASs), junior residents (JRs) (PGY2/PGY3), and senior residents (SRs) (PGY5/PGY6) during trauma activation and emergency surgery. METHODS We preformed a prospective study enrolling participants over eight 24-hour calls in our Level I trauma center. Stress was assessed based on decrease in HRV, which was recorded using body worn sensors. Stress was defined as HRV of less than 85% of baseline HRV. We collected subjective data on stress for each participant during calls. Three groups (ASs, JRs, SRs) were compared for duration of different stress levels through trauma activation and emergency surgery. RESULTS A total of 22 participants (ASs: n = 8, JRs: n = 7, SRs: n = 7) were evaluated over 192 hours, which included 33 trauma activations and 50 emergency surgeries. Stress level increased during trauma activations and operations regardless of level of training. The ASs had significantly lower stress when compared with SRs and JRs during trauma activation (21.9 10.7 vs. 51.9 17.2 vs. 64.5 +/- 11.6; p < 0.001) and emergency surgery (30.8 +/- 7.0 vs. 53.33 +/- 6.9 vs. 56.1 +/- 3.8; p < 0.001). The level of stress was similar between JRs and SRs during trauma activation (p = 0.37) and emergency surgery (p = 0.19). There was no correlation between objectively measured stress level and subjectively measured stress using State-Trait Anxiety Inventory (R-2 = 0.16; p = 0.01) among surgeons or residents. CONCLUSIONS Surgeon wellness is a significant concern, and this study provides empirical evidence that trauma and acute care surgeons encounter mental strain and fail to recognize it. Stress management and burnout are very important in this high-intensity field, and this research may provide some insight in finding those practitioners who are at risk. LEVEL OF EVIDENCE Epidemiologic study, level II.