0140 Examining The Effects Of Moderate Blast Exposure On Sleep: Observations From Specialized Military Training Exercises

Abstract

Abstract Sleep disruption is prevalent among active military personnel. For some, there is the added environmental stressor of repetitive, low-level blast exposures. Though there are subjective reports that blasts affect sleep, objective measurement is lacking. In this observational study, we examined sleep across 2-week military training with exposure to blast. Across all training days blast intensity was low (<2psi), except for a single day, Day 7 (peak pressure M=7.99psi, SD=1.66). As such, we predicted that sleep would be acutely fragmented and shortened following that moderate blast exposure. Participants were 31 males, aged 25-42 years. Sleep efficiency (SE) and total sleep time (TST) were measured using wrist-worn actigraphy. Peak intensity of blast exposure was captured daily via helmet-mounted pressure sensors. Training Day 5 was selected as baseline as participants were not exposed to blast training or night operations. Pairwise comparisons t-test (TST) and Wilcoxon matched-pairs (SE) were run to compare sleep at baseline to the training days (6-10). TST was consistently short (daily M≤6hours) and there were no significant differences in TST between the training days. Although SE was significantly different between Day 5 and Day 8 (reflecting sleep following blast on Day 7), this reduction in sleep efficiency did not seem to reflect an acute effect of blast, but a more general decline in SE observed between baseline and Days 7, 8, 9, and 10 (p