Abstract Introduction Emergency responders experience high exposure to traumatic events, yet early predictors of vulnerability versus resilience remain unclear. Although sleep disturbance is common in this profession due to increased stress exposure and disordered sleep, it is unclear whether habitual sleep prior to stress exposure prospectively predicts later stress reactivity. Building on evidence from our recent systematic review that subjective sleep often outperforms objective metrics in predicting psychological outcomes, this ongoing 1.5-year longitudinal study tests whether baseline subjective and objective sleep measures predict stress-related symptoms during the transition from academy training into active duty. Methods Fire, EMS, and police recruits completed a 7-night portable EEG assessment at baseline (T1; pre-academy) measuring sleep efficiency (SE%), total sleep time (TST), and REM duration. Subjective sleep was assessed using the Pittsburgh Sleep Quality Index (PSQI). Stress and well-being were evaluated at academy graduation (T2), 6 months into duty (T3), and 12 months into duty (T4), using the Acute Stress Disorder Scale (ASDS), PTSD Checklist for DSM-5 (PCL-5), and Professional Quality of Life Scale (ProQoL). Analyses included participants who reported at least one stressful or traumatic event after baseline. Pearson correlations examined whether T1 sleep predicted average post-baseline stress outcomes across T2–T4. Results Baseline subjective sleep quality was the strongest and most consistent predictor of later psychological functioning. Higher PSQI scores (worse subjective sleep) predicted greater acute stress, higher PTSD symptoms, more burnout, and greater secondary traumatic stress across the first year of duty. Among objective metrics, sleep efficiency was selectively associated with higher compassion satisfaction, suggesting a potential resilience marker. Total sleep time and REM duration were not significantly associated with any outcomes. Overall, subjective sleep measures predicted vulnerability to trauma-related symptoms more robustly than objective sleep architecture. Conclusion Habitual subjective sleep quality prior to academy training is a significant predictor of later sensitivity to traumatic stress among emergency responders, whereas objective sleep measures show limited predictive value. These findings highlight subjective sleep as an early indicator of risk and support incorporating sleep-based screening to guide preventive interventions during emergency responder training. Support (if any) This work was supported by NSF CAREER Award 2237419 to Itamar Lerner.
Larios et al. (2026) studied this question.