Sleep Quality and Physiological Stress in Emergency Physicians During 24‑Hour Shifts: A Wearable‑Based Occupational Health Assessment

BACKGROUND: Shift-based work schedules may disrupt circadian rhythm and adversely affect sleep and stress regulation among healthcare workers. Emergency physicians are particularly exposed to high-intensity workloads and prolonged 24-hour shifts, which can increase occupational strain. Methods: This study was conducted between April and December 2024 in a tertiary emergency department. Participants wore a smartwatch continuously for 30 days to record sleep architecture and heart rate variability-based stress indicators. Physiological parameters obtained during 24-hour shifts and at home were compared. Analyses were performed across four professional-experience groups. RESULTS: Sleep duration, deep sleep percentage, deep sleep continuity score, breathing quality score, and overall sleep score were lower during 24-hour shifts, whereas light sleep percentage, nighttime awakenings, and stress levels were higher (all p < 0.001). Physicians with greater professional experience had longer sleep duration and lower stress levels during 24-hour shifts compared with early-career residents. Multiple linear regression analysis indicated that professional experience was the only independent predictor of stress levels during shifts. CONCLUSIONS: Shift work in emergency medicine is associated with impaired sleep quality and increased physiological stress. Professional experience appears to mitigate stress responses but does not fully restore sleep quality. These findings support the need for targeted occupational strategies, including optimized workload distribution and structured support for early-career physicians, to improve well-being and ensure patient safety in high-intensity clinical environments.