Assessment of Sleep Disruption and Sleep Quality in Naval Special Warfare Operators

Abstract

Little is known about sleep in elite military populations who are exposed to higher operational demands, unpredictable training, deployment, and mission cycles. Twenty-nine Naval Special Warfare (NSW) Operators wore an actiwatch for an 8-day/7-night period for objective sleep assessment and completed a nightly sleep log. A total of 170 nights of actigraphically recorded sleep were collected. When comparing objectively versus subjectively recorded sleep parameter data, statistically significant differences were found. Compared with sleep log data, actigraphy data indicate NSW Operators took longer to fall asleep (an average of 25.82 minutes), spent more time awake after sleep onset (an average of 39.55 minutes), and demonstrated poorer sleep efficiency (83.88%) (ps < 0.05). Self-reported sleep quality during the study period was 6.47 (maximum score = 10). No relationships existed between the objectively derived sleep indices and the self-reported measure of sleep quality (rs = -0.29 to 0.09, all ps > 0.05). Strong inter-relationships existed among the subjectively derived sleep indices (e.g., between self-reported sleep quality and sleep efficiency; r = 0.61, p < 0.001). To our knowledge, this is the first study to objectively and subjectively quantify sleep among NSW Operators. These findings suggest sleep maintenance and sleep efficiency are impaired when compared to normative population data.