INTRODUCTION: Burnout and depression is higher in trauma surgeons as compared to surgeons in other specialties. Clinical practice for many acute care surgeons (ACS) includes in-house call (IHC). The goal of this study was to quantitate physiologic stress among ACS who take IHC. METHODS: ACS with IHC responsibilities from two Level I trauma centers were studied. Participants wore a fitness and heart rate variability (HRV) device over 3 months. HRV was categorized as normal if 85% of baseline, moderate stress when HRV <85% but >50%, and high stress when HRV< 50%. RESULTS: 1421 nights were recorded among 17 surgeons (35.3% female; mean age 45.5 years). Excluding IHC, mean HRV鈥?鈥?2.23, and 95.63% of days were consistent with moderate or high stress. Post-call day 2 had significantly highest percentage of high stress (65.82%, p鈥?鈥?.0495). High and moderate stress levels returned to baseline on post-call day 3. CONCLUSIONS: High and moderate stress beyond IHC is common among ACS. Future study is needed to determine consequences of persistent stress and identify factors which impact recovery after IHC.