Physical and Behavioral Characteristics Associated with Sleep Duration in a Cohort of United States Army Reserve Soldiers

Background Insufficient sleep may impact U.S. Army Soldiers’ well-being and medical readiness. This analysis investigated the relationship between modifiable physical and behavioral characteristics and sleep duration among U.S. Army Reserve (USAR) Soldiers. Methods This was an analytical cross-sectional evaluation of U.S. Army Reserve Soldiers. Demographics and health characteristics were obtained from an electronic survey. Univariate and multivariable linear regression models were used to estimate the relationship between modifiable risk factors known to affect sleep duration and the overall number of hours slept per night. Results Respondents consisted of 1,423 male and 514 female USAR Soldiers. Three modifiable risk factors were associated with sleep duration; body mass index, reported stress, and caffeine consumption. Sleep duration decreased by 1.9 minutes per night for every one unit increase in body mass index (p<0.001). Sleep duration decreased by 17.9 minutes per night for those reporting moderate to high stress compared to low stress (p<0.001). Sleep duration decreased by 11.2 minutes per night for each step increase in the frequency of caffeine consumption six hours before bed. Compared with participants who rarely or never consumed caffeine during this period, sleep duration was 11.2 minutes shorter for those who did so sometimes and 22.4 minutes shorter among those who did so most of the time or always (p<0.001). Conclusion Sleep duration among USAR Soldiers is associated with certain modifiable risk factors. Education and health interventions targeting USAR Soldiers or those like them, should consider body mass, influences of stress, and caffeine intake and caffeine intake timing.