A cross-sectional study of sailors assigned to naval warships in the United States found that workload and uncomfortable mattresses could be targeted to address chronic insufficient sleep, according to findings published in the Journal of Sleep Research.
Study researchers invited active-duty Surface Force sailors (N=11,738) via email to complete a survey about demographics, work conditions, and sleep. They asked participants how many hours of sleep made them feel well-rested, how many hours they sleep at home, how many hours they have the opportunity to sleep on-board, and how many hours of sleep they get on-board.
The average reported time spent sleeping on-board was 327 (standard deviation [SD], 92) minutes.
There was a normal distribution for the amount of time required to feel well-rested, with the majority requiring about 7 hours of sleep; more mass was in the range of 7-9 hours. The distribution of sleep time obtained at home strongly corresponded with the responses to the amount of time needed to feel well-rested.
The distribution for the amount of sleep opportunities and amount of actual sleep obtained on-board was skewed, in which there were fewer opportunities for sailors to sleep on-board such that they feel sufficiently rested.
No associations between sleep time on-board were observed for sex, age, paygrade, time on-board, years of service, department, ship class, or operational phase. All subgroups obtained between 71% and 84% of sleep required to feel well-rested.
The strongest correlations between sleep obtained were observed between workload (Pearson r, -0.33), required meetings (Pearson r, -0.26), required inspections (Pearson r, -0.25), drills (Pearson r, -0.24), uncomfortable mattress (Pearson r, -0.17), and invasive light (Pearson r, -0.15).
This study was limited by its cross-sectional design. Additionally, causal relationships between chronic insufficient sleep on-board with environment could not be made.
These data indicated that active-duty sailors were not obtaining sufficient sleep while on-board. Optimizing workload and providing comfortable mattresses may be effective strategies for promoting sufficient sleep in the United States Navy.
Russell DW, Markwald RR, Jameson JT. Self-reported sleep and sleep deficiency: Results from a large initiative of sailors attached to U.S. Navy warships. J Sleep Res. 2021;e13397. doi:10.1111/jsr.13397