Sleep loss is related to unstable stationary balance in U.S. Army soldiers in an operationally-relevant context

Background: Sleep loss negatively impacts stationary balance in a laboratory setting, but few studies have examined this link in a naturalistic environment. We tested this relationship in U.S. Army soldiers that often undergo mission-driven sleep loss and who conduct high-risk operations on precarious terrain. Methods: Stationary balance was tested before and after a mission night. Results: After mission-driven sleep loss, in more difficult conditions (but not easy conditions) balance was more unstable and more variable than a rested baseline condition. Furthermore, habitual sleep quality prior to sleep loss predicted the balance decrement after sleep loss. Conclusions: Therefore, mission-driven sleep loss may negatively impact soldier balance, but better sleep prior to the mission may mitigate these negative effects.