When Medical Residents (MR) and Medical Students (MS) are assigned to the demanding environment of an Emergency they inevitably encounter stress. The aims of this study are to measure short-term heart rate variability (HRV) before and after shifts, estimate perceived stress levels, and assess the recovery patterns after their shifts.

We assessed HRV parameters in MS and MR using the wristband physiological monitor Polar® Verify Sense before and after day (DS) and night shifts (NS). Perceived stress levels were evaluated using the simplified State Trait Anxiety Inventory (STAI-S6) and the Subjective Units of Distress Scale.

This study included 60 participants of which 55% were female with a mean age of 26 years. MS presented significant reduction in sympathetic nervous system index after DS [0.68 (0.01–2.42) vs −0.22 (−0.75–1.13), p < 0.01] and NS [0.87 (−0.28–1.45) vs 0.06 (−0.70–1.04), p < 0.01], while MR maintained the same levels of sympathetic activity [DS: 1.17 (0.04 –2.88) vs 0.93 (0.50–1.41), p = 0.14; NS: 1.37 (0.76–2.21) vs 1.29 (0.35–2.18), p = 0.40]. Psychological data from STAI-S6 showed statistically significant differences when comparing before and after DS in both groups, with more perceived stress after than before DS (MS: 12 ± 4 vs 14 ± 4, p = 0.04; MR: 14 ± 4 vs 16 ± 4, p = 0.04), which was not observed at NS (MS: 12 ± 3 vs 12 ± 3, p = 0.84; MR: 15 ± 3 vs 15 ± 4, p = 0.40).

Short-term HRV recordings before and after day or night shifts among MR and MS revealed heightened sympathetic activity preceding each shift, with a more sustained increase observed in the MR population and more perceived stress after day shifts in both groups.