Tachycardia may be indicative of mental stress, which in turn can decrease performance, reduce information processing capacity, and hinder memory recall. The objective of this study is to examine heart rate trends present among emergency medicine trainees over a standard emergency room shift to measure the frequency and severity of stress experienced while on shift.We assessed heart rate in emergency medicine residents using the Empatica E4 device, a mobile wrist-worn physiological monitor. The 31 consenting residents received training in wearing the monitor and uploading the data during a typical critical care shift. Data was deindividualized, compiled, and analyzed with descriptive statistics using Microsoft Excel.Data collected from 31 critical care shifts illustrated that the mean range in HR was 53.9-162.7 bpm per shift and the overall range in HR across all shifts was 49-202.7 bpm. There was a mean of 10.2 peaks in the 120-129.9 bpm range, 11.3 peaks within 130-159.9 bpm, and 1.06 peaks above 160 bpm per shift. The mean length of time that HR rose above 130 bpm was 660.6 s per shift. Only 2 of the 31 shifts examined did not have any accelerations above 130 bpm.Continuous monitoring of HR in emergency medicine residents during standard critical care shifts using a wrist-worn device found marked elevations suggestive of episodic tachycardia.