Project Abstract Sudden cardiac death (SCD) has been the leading cause of on-duty death (ODD) in the fire service over the past several decades, accounting for 51.6% of all ODDs in 2019. The primary factors that contribute to SCD among firefighters are overexertion and stress, and SCD is most likely to occur during fire suppression and alarm response. When an emergency occurs, firefighters are alerted/awoken by loud mechanical bells. This high noise level may induce a stress response triggering a cardiovascular event. In fact, “high levels of environmental noise fuel cardiac risk” by stimulating the amygdala and inflaming the arteries. While other companies have attempted to modernize alerting systems, they failed to address the problem of stressful alarms because they focus on alerting “stations” not individual firefighters. A significant need exists to develop a less stressful alerting system for firefighters. The objective for this SBIR Phase I R43 research study is to develop a commercially viable Fire Fighter Alerting System (FFAS) comprised of proprietary wearables and optional bed shakers called BunkAlerts. Collectively “personal alerting devices,” the wearables and BunkAlerts enhance the alerting process for firefighters by replacing jarring audible alarms with tactile alerts delivered to the firefighter's wrist. This alternative approach is designed to significantly decrease tachycardic responses associated with legacy alerting systems. Meeting this need has the potential to reduce firefighter ODDs and improve the quality of life for the 15.4 million firefighters around the world. The feasibility of EaseAlert's FFAS is reinforced by preliminary data collected during field testing with six (6) fire departments in three (3) states where EaseAlert's prototype FFAS (“Gen 1”) successfully delivered over 10,000 alerts to firefighters called to an emergency with no calls missed. The potential for our FFAS to reduce stress and SCD risk among firefighters is supported by preliminary data which shows that: 1) noise triggers a startle response and 2) tactile alerts are associated with positive valence and high arousal. The proposed research will be accomplished with two aims: Aim 1 – develop a commercially viable FFAS and Aim 2 - determine the effectiveness of the FFAS in reducing cardiac reactivity and improving sleep. EaseAlert will leverage the Gen 1 FFAS as a foundation for developing its Gen 2 FFAS outlined in Aim 1. Aim 2 will test two study hypotheses in a within-subjects pilot clinical trial design: (H2.1) that EaseAlert will result in a significant reduction in the stress response to alarms compared to traditional auditory alerting systems, and (H2.2) EaseAlert will result in a significant improvement in sleep efficiency. Upon successful completion of Phase I, our Gen 2 FFAS and pilot trial will demonstrate technical merit and feasibility for Phase II. Phase II will conduct a large randomized parallel groups clinical trial powered to exami...