First responders are uniquely vulnerable to chronic sleep deprivation. Years of conditioning — waking abruptly to station alarms — train the body to stay perpetually alert, making deep, restorative sleep difficult to achieve both on and off the job. This hypervigilance, driven by the sympathetic nervous system's fight-or-flight response, doesn't simply switch off at retirement.

Why are some calls harder to forget? Our brains are wired to save events in an effort to protect us from future harm.