Acute caffeine intake before and after fatiguing exercise improves target shooting engagement time
The authors examined the effect of caffeine on target detection and rifle marksmanship during simulated combat operations after prolonged exercise. This experimental study had 12 participants from various military reserve units receive body-mass specific doses of caffeine or placebo. The authors conclude that, based on the results, caffeine ingestion improves target detection and engagement speed during vigilance situations (e.g. sentry duty), but is not effective during more complex operations that require higher levels of cognitive processing and fine motor control and coordination (e.g. discriminating between friend and foe during combat situations).
Gillingham, R. L., Keefe, A. A., & Tikuisis, P. (2004). Acute caffeine intake before and after fatiguing exercise improves target shooting engagement time. Aviat Space Environ Med, 75(10), 865-871.
Gillingham, R. L., A. A. Keefe, and P. Tikuisis. "Acute Caffeine Intake before and after Fatiguing Exercise Improves Target Shooting Engagement Time." Aviat Space Environ Med 75.10 (2004): 865-71.