What This Means
This research examined how military personnel's beverage drinking habits cluster together and whether these patterns relate to their sleep and fatigue. Among 1,155 active-duty Spanish Army members, researchers used a statistical technique called latent class analysis to group soldiers based on how frequently they consumed caffeinated beverages, sugary drinks, and energy drinks. Three distinct groups emerged: a low-frequency group (about 48% of soldiers), a medium-frequency group (about 28%), and a high-frequency group (about 24%). The high-frequency group consumed all three beverage types more often than the others.
This research suggests that soldiers who frequently consumed these beverages together tended to report sleeping about 14 fewer minutes per night, having roughly 2 percentage points lower sleep efficiency, and experiencing more physical fatigue compared to those who consumed these drinks less frequently. These associations held even after accounting for many other factors like age, job type, exercise habits, alcohol use, and smoking. Importantly, the study found patterns across beverage types together rather than isolating any single drink's effect, and it could not determine whether the beverages caused the sleep and fatigue differences or whether fatigued, poor-sleeping soldiers simply reached for more of these drinks.
The practical takeaway from this research is limited by the study's design—it captured a single snapshot in time using self-reported data, and the differences observed, while statistically significant, may or may not be large enough to matter in daily life. The beverages were tracked by frequency rather than exact amounts consumed or timing relative to sleep. Future studies that follow soldiers over time and record specific drink types, amounts, and when they are consumed would be needed to better understand whether changing beverage habits could meaningfully improve sleep and reduce fatigue in military populations.