0199 Chronic Sleep Debt In Soldiers Is Exacerbated By Mission Training: An Assessment Of Subjective Sleep Characteristics

Abstract

Military operations require vigilance and performance under stressful conditions while functioning with little sleep. Performance impairments (i.e., marksmanship, vigilance, executive function) have been linked with reduced sleep duration and sleep quality, as well as perceived sleepiness and fatigue. This research assessed changes in the Soldier subjective sleep profile when conducting a 72-hour military exercise during a stateside period between deployments. Performance of forty-six Soldier volunteers [42 males (mean age 24.5±4.2)] was assessed during a company-wide mission exercise. Subjective sleep duration, quality, and sleepiness were collected two weeks prior to mission and immediately post-mission, utilizing a modified Pittsburg Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS). Sleep duration pre-mission (M=5.77 hours, SD=1.45) was significantly higher than post-mission (M=3.94 hours, SD=1.34) (p<.0001), and significantly different across platoon-group (p=.027). However, mean sleep duration pre-mission was lower than the Army-recommended 7-8 hours, indicating chronic sleep debt across platoons prior to mission commencement. Additionally, there were no differences in PSQI scores across pre- and post-mission, with 83% categorized as “poor sleepers” (PSQI > 5) pre-mission (M=7.85, SD=3.83) and ending with 98% “poor sleepers” post-mission (M=8.71, SD=2.45). Perceived sleepiness also significantly increased across the mission (p<.0001); however, ESS scores for both pre- and post-mission indicated clinically relevant levels of excessive daytime sleepiness (ESS > 10) (pre: M=10.61, SD=5.76; post: M=17.57, SD=7.48). The time between deployments is intended as a recovery period, where Soldiers can recharge, reconnect, and train. However, even when stateside, Soldiers may be at risk for chronic sleep restriction and poor sleep quality leading to excessive daytime sleepiness even before participating in mission training and future deployment. Further investigation of potential influencing factors is warranted (i.e., Unit type, command climate, training regimes, work-life balance). Furthermore, platoon characteristics may influence factors leading to sleepiness during mission activities. Further analysis will explore performance degradations associated with daytime sleepiness and individual platoon differences, such as leadership, qualifications, and group cohesion. Military Operational Medicine Research Program and Natick Soldier Research Development Engineering Center.