Sleep Patterns of U.S. Navy Personnel Transitioning from Training to Fleet Assignments

INTRODUCTION: It is often assumed that the sleep received by military personnel when they are in training is better than that they receive in their fleet assignments. The current study assessed this assumption. METHODS: Using wearable devices, this prospective naturalistic study monitored the sleep patterns of 99 fit-for-duty (median age = 38 yr; 91 males) U.S. Navy surface warfare officers for a median of 340 d per subject. Data were collected while the subjects attended standardized training in a shore-based facility and during their follow-on fleet assignments. RESULTS: Subjects slept on average 6.79 ± 0.578 h/d (64.7% slept on average <7 h/d and 6.06% slept <6 h/d). Sleep deprivation was evident in both environments but was more pronounced in the fleet assignment. Subjects slept more on weekends (+0.54 h/d in training and +0.84 h/d in fleet assignment); however, this extra sleep was not enough to account for the sleep loss during weekdays. In addition, sleep patterns were more irregular in the fleet. For subjects' major sleep episodes, heart rate, lowest heart rate, respiratory rate, and respiratory rate variability were higher in training. Sleep efficiency and heart rate variability did not differ between the two settings. DISCUSSION: Our results shed light on the differences in sleep patterns and cardiac/respiratory activity indices between a training environment and fleet assignments. Daily sleep duration and sleep regularity are better in a training environment. The changes we identified in cardiac activity, respiration, and sleep efficiency need to be further assessed by focusing more closely on sleep stages. Shattuck NL, Matsangas P. Sleep patterns of U.S. Navy personnel transitioning from training to fleet assignments. Aerosp Med Hum Perform. 2026; 97(5):327-332.