Caffeine to optimize cognitive function for military mission-readiness: A systematic review and recommendations for the field

Context: In 2001 the Institute of Medicine (IOM) released a report on the use of caffeine during sustained military operations in which recommendations for research and practice were made. Objective: This systematic review serves as an update on the current quality of the evidence and addresses gaps in the current literature surrounding the effects of caffeinated foods and beverages on cognitive functioning in healthy adult populations exposed to military-like moderators. Data Sources: PubMed, CINAHL, Embase, PsycInfo, and the Cochrane Library were searched. Study Selection: Peer-reviewed randomized controlled trials published in the English language since 1998 were eligible. Data Extraction: Twenty-five trials were included and assessed for methodological quality, and descriptive data were extracted according to each military-like moderator identified. Data Synthesis: Moderators included sleep deprivation (n ¼ 17), physical or mental exertion (n ¼ 4), sleep deprivation combined with a sustained military operation (n ¼ 3), and physical exertion combined with low ambient temperature (n ¼ 1). Conclusions: The effects of caffeine supplementation on cognitive functioning in sleep-deprived subjects included improvements in attention and vigilance, complex reaction time, and problem solving and reasoning in the trials reviewed. These findings are consistent with the conclusions reached in the 2001 IOM report. This review contributes to the field by addressing gaps outlined in the IOM report.