| Twelve reservists ingested 5.0 mg/kg of caffeine (C) or placebo (P) one hour before beginning a 2.5 h loaded march and 1.0 h sandbag wall construction task. Following exercise, participants were given a redose of 2.5 mg/kg of C or P. One hour postingestion, participants commenced a 2.5 h shooting session on a small arms trainer, which included friend-foe (FF) and vigilance (VIG) tasks. In total, four counterbalanced dose-redose experimental trials were conducted: PP, PC, CP, and CC. Performance measures during the shooting session included the number of shots taken (NS), engagement time (ET), and marksmanship. Results indicated that C did not affect exercise or shooting performance during the FF task. NS and ET improved with CC during the VIG task. In conclusion, C improves target detection and engagement speed during vigilance situations, but is not effective during more complex operations requiring dual task proficiency. |
