Effectiveness of Psycho-Physiological Portable Devices to Analyse Effect of Ergogenic Aids in Military Population

Caffeine is one of the ergogenic substances most used by warfighters in current operation areas, but the effect on the organic response and operational performed is already poor knowledge. This research aimed to study the acute effect of 400 mg of caffeine monohydrate on the psycho-physiological response and rifle marksmanship of warfighters during a close quarter combat simulation. We analysed parameter of heart rate, blood lactate, cortical arousal, state anxiety and marksmanship of 20 Spanish Army veteran warfighters before and after a close quarter combat simulation in a double-blind procedure, also a correlation analysis was conducted between all the study variables. Marksmanship of warfighters did not improve with the caffeine ingestion, but it produced an increase in blood lactate concentration (caffeine: 1.9 ± 0.5 vs. 9.2 ± 1.1 mmol.l^-1; placebo: 1.8 ± 0.7 vs. 6.9 ± 2.2 mmol.l^-1), cortical arousal (% of change: caffeine: 2.51; placebo: -1.96) and heart rate (caffeine: 80.0 ± 7.2 vs. 172.9 ± 28.2 bpm; placebo: 79.3 ± 6.4 vs. 154.0 ± 26.8 bpm). In addition, higher heart rate values correlated negatively with marksmanship in close quarter combat. We concluded that caffeine intake did not improve the warfighters rifle marksmanship in close quarter combat possibly due to the increase in the physiological response.