1118 The Impact of Live Fire Training on Infantry Members’ Self-Reported Sleep and Stress

Abstract Introduction Poor sleep is both a predictor of decreased operational performance and a consequence of military operational environments and schedules. We sought to understand the effect of one type of military environmental exposure, blast overpressure, on Soldiers’ sleep quality. As part of a larger study, we conducted a 2 (control / live fire) x 2 (pre / post) within-person design in which 25th Infantry volunteers completed sleep and stress ratings immediately before and after two training events. The control training event consisted of a three-day preparatory exercise with similar operational stresses to the subsequent live-firing event. For both events, the participants were exposed to periods of extended wakefulness, moving and positioning 777 howitzers, and intense physical activity. The live fire training event involved exposure of between 2 – 20 2L charges from 777 howitzers. Methods Twenty-one Cannon Crewmembers from the 25th Infantry Division Artillery 3rd Battalion completed the pre-control data session (three female, mean age 23.86 years, mean YOS 2.88 years). Nineteen participants (2 female, mean age 23.2 years, mean YOS 3.05 years) completed both the pre-live fire and post-live fire data sessions and 16 completed all four sessions. Self-reported 5-point Likert scale ratings of sleep and stress and a blast exposure survey were collected at each session. Results Participants reported consistent ratings of suboptimal sleep in the control event (pre-mean = 3.06 (1.04); post-mean = 3.29(1.31)), but significantly worsened sleep from pre-live fire to post-live fire (mean difference = 0.82, SE = 0.27 t(18.1) = 3.04, p = 0.034). Similarly, they reported stable levels of modest stress for the control event (pre-mean = 2.48 (1.30); post-mean = 2.72(1.07) but a nonsignificant trend towards increased stress from pre-live fire to post live fire (mean difference = 0.41, SE = 0.21), t(17.8) = 2.05, p =.21). Blast exposure survey data was not analyzed due to within-person inconsistency. Conclusion Results suggest that physiological and psychological stress from blast exposure is multi-dimensional and that sleep/wake dynamics may serve as a predictive tool for greater monitoring and mitigation of blast exposure. Support (if any) This work was supported by Army Applied SBIR W51701-23-C-0269.